Messages

That 5 pin DIN output is not balanced. 

Pin 2 is Common/Ground.
Pins 1 and 3 are shorted together, and are the signal for the Pianet.
Pins 4 and 5 are shorted together, and are the signal for the Clav.

If you send the Duo's DIN 1 and 3 (or 4 and 5)  to an XLR's  + and - (pins 2 and 3), and Duo DIN 2 to XLR pin 1, a true XLR balanced input will subtract pin 3 from 2, hence the signal from itself, and you will end up with nothing.

So other than convenience or compatibility with older European stereo equipment,
the 5 pin DIN is no better than 2 separate 1/4" unbalanced instrument cables hooked to the separate Pianet and Clavinet outputs.

The fuse is on the output of the amp, between the power devices and the speakers.

If you have already switched the amp module board, the problem could be with the power output devices (DC offset, thermal runaway, etc.). The power devices (two TO-3 case NPN BJTs per channel) are mounted to the outside of the heat sink underneath black anodized covers.  If you end up having to change them, you will need to also remove the board(s) above the sockets so that you can properly seat and remount the new devices.  Pay attention to the mica insulators and thermal grease. Power devices need not be super well matched on a Janus, but should both come from the same manufacturing lot (part number and date code) so that they are similar in their characteristics. Note that if anything gets changed (board, power devices, etc.) you must properly reset the offset and bias trimmers on the amp cards. 

It is also possible that something is wrong with your speakers or the wiring after the fuse, including the headphone jack.  Could be an intermittent short, too low of an impedance to ground, etc.  Compare the two channels with a meter while moving wires around and see if the meter jumps. Intermittent problems can be very tricky to find and recreate reliably.

Run some tests by switching the 1/4" speaker cables and/or the amp card wiring harnesses (one at a time) if you haven't done so already and see if the OTHER fuse or SAME fuse blows.   If you do your bookkeeping right and keep track of what changes you make, you'll get more information that will help lead you to the source of the problem.

Good luck!  Let us know how it goes.

The other Tim

In general, I would strongly advise that you DO NOT replace ORIGINAL hammer tips if they are not deeply grooved, split, or otherwise worn. 

The wood core tips certainly aren't bad unless the rubber wrap is cracked/split or pretty severely indented from heavy use.  The original rubber tips are made from a different compound than the grommets (we've done the testing/research), and also are not under the constant stress/pressure that the grommets endure from the tonebar springs.  They generally age very well if not damaged.  If the bass tips are still squishy and soft, and the hardness increases as you move up through the various sections, you are good. Only replace them if they are completely dried out and crumbling apart or have obvious deep (1/16"+) grooves, cracks below/around the grooves, chunks missing, or other heavy wear from playing/use. Even deeply grooved tips can be trimmed back if they aren't split or cracking, followed by an escapement and strike line readjustment. One can almost always hear a bad or problematic hammer tip when compared with neighboring good ones.  With experience, eventually one can hear it without needing to do comparisons.

Generally, only the very early rubber hammertips ('70-'71) that had colored dye mixed in them need to be replaced due to a chemical degradation that occurs from the dye. All hammertips made without the dye (late '71 onwards) have a colored stripe painted on one side for identification.

Too many times people throw out perfectly good tips and dampers due to marketing hype and groupthink, and then are not happy or struggle to get good results.  Many believe that replacing all the old parts will make their piano sound better, when it is more often issues with action setup, voicing, and tuning creating the problems.  Very, very few Rhodes came out of the factory actually set up properly.  Exceptions are far and few between.  Most need significant tweaks and adjustments to get into the sweet spot.

Getting a Rhodes setup properly requires really good ears, a deep understanding of the relationships and tradeoffs in the Rhodes design, how to manipulate and optimize such tradeoffs, excellent mechanical skills, and lots of patience.  If you have a suitcase, you also need electronics skills and knowledge. Experience also helps since one then has a background of what works and what doesn't, and how to identify, isolate, and eliminate issues.  YouTube won't, unfortunately, get you very far.

Please appreciate that I state this unequivocally as a manufacturer and supplier of new parts, including hammertips. Tread lightly.  Don't make extra work for yourself and end up with less than good results.  If it really ain't broke, DON'T attempt to fix it!

Tim

CTS made the Alnico speakers for Wurlitzer.  The EIA code stamped on the speaker baskets begins with 137.

We have seen several of these early 200s now with two different cone styles as noted.  Unfortunately we do not have any pictures available currently.  This was how the pianos were shipped from the factory.

The left speaker cone and surround was designed to give more low end response, and the right speaker had a smooth stiff cone and surround
which was better for high frequencies.  This, in effect, would put the treble on the right side of the piano (where the high keys are) and the bass on
the left side of the piano to give the player a more realistic experience like, perhaps, an acoustic piano.

This was probably a less expensive route to deliver this effect than doing it electronically (bi-amping, etc.), as electronics were more expensive than speakers at the time.  Nowadays the opposite is true.

This technique was also used extensively in organs from the same time period.  Many of the Hammond organs with built in speakers (M-100, for example) had 2 speakers with different cone designs so that the entire frequency spectrum would be reproduced clearly.  These speakers were simply wired in parallel to the main power amp- no special electronics or crossover network needed.  The mechanical design and materials used for the speakers themselves are what determined their frequency response.

Tim

To me it sounds like it is voiced improperly- it is pure overtone, no fundamental.  The tip of the tine is too low in relation to the pickup.

If the note is in tune with the note an octave above it (or very very close) then it is not the spring.

Pop the lid, find the offending note/tine and then back off on the voicing screw (the phillips head furthest from you) that holds the tonebar in place (there are 2 screws) until you get it sounding like the neighboring notes.

If it hits the pickup, loosen the pickup and slide it back a tiny bit.  Again, compare to neighboring notes and adjust until it is even with those.

Good luck!

And to add yet more to this experiment...

I think we might be best able to compare the difference in sound due to input impedance if that is the ONLY thing being altered.  This is the main point of the argument- that the input impedance affects the sound- and that 1Meg makes a difference compared to 10Meg, so it should be the only thing that gets changed in a comparison study.

The Countryman should be used in both recordings but in one recording, a 1.1Meg resistor should be added in parallel with the input to the Countryman.  This will then provide almost a 1 Meg input impedance (if the Countryman's own impedance is close to exactly 10Meg as advertised) and the Rhodes should respond accordingly.

This insures that other things in the signal path are held constant and completely out of the question.  Subbing in a Radial DI changes a lot more than just the input impedance.

It will be hard to duplicate 2 passages exactly on the Rhodes since a human will be playing in both performances a little differently... so this alone might color perceptions of what sounds better.
Both samples must also be normalized so that their amplitude levels are very, very, closely matched- as it is normal for human's to always pick the sample that is a little louder as "sounding better".

This is a really tough experiment to pull off properly in a very well controlled manner!

Tim

On the keys with the longest damper arms (usually the last 2 octaves on a 73 key), the longer damper arms limit the upward travel of the hammers so they never get to the point where they can severely overshoot- the hammer rebounds off the damper arm and bounces back.  That is why you hear that loud click sound on the upper keys.

On the lower keys, since the harp is not in place, and the damper arms are shorter (only slightly in the midrange, but they are enough shorter), the hammers can and will overshoot and can get stuck beyond stop-lock.

This would happen whether or not you have the bump mod installed.  The bump, when properly placed, should be out of the way of the hammer cam by the time stop-lock is reached.  All the bump does is lighten the action and makes the piano easier to play because the hammer pivots on a smaller area of contact with the pedestal.

You are basically chasing a 'problem' that isn't real.  When you put the harp back onto your piano, the hammers will rebound off the tines and enter stop-lock- they will never be able to travel up as far as they do in your video without the harp in place.

Those hammers in the upper range are hitting the longer damper arms and rebounding off of them. Actuate the full travel of a low hammer and high hammer slowly using your hand (not by depressing a key) and you will see what is going on.

Good luck!

We would not need the whole piano sent in, just the VariVib board and bracket itself (what you purchased from us.) 
On your end, you would need to remove the old neon lamp and drill open the hole that the lamp was clipped into to accomodate the new LED.

Yes, the LED was put there initially to verify operation and proper vibrato tracking.  It wasn't until we started having jewels made that we started remoting the LED... and not all clients want that feature anyway.

Thanks,
Tim

Hello,

Glad to hear you are happy with our Vibrato upgrade!  We also see that you purchased our amp board, which we also appreciate.

If you would like to discuss moving the LED, please contact us directly.  It can be changed to any color you'd like, and we have clear jewels available so that you can replace the orange one in your faceplate if you decide to choose a different LED color.

We do this mod for our clients quite often for in-house work, but don't offer it as a user install since it involves desoldering, soldering, and some metal work.  A resistor may also need to be changed depending on the LED you choose.  We would be happy to modify your unit to utilize a remote LED of your choosing.  We generally don't recommend soldering in the field since many end users do not have the proper soldering equipment to do fine PCB work without possibly causing damage- which would void the warranty on our product.

Best regards,
Tim
retrolinear.com

It is likely a ground loop causing your problem.

The key giveaway is "even when powered off".

Grab a ground cheater block from the hardware store.  They are little gray blocks with a 3 prong outlet and a 2 prong plug.  The 3rd prong is replaced by a green metal tab on the plug end.  Just don't let that tab touch anything grounded or just cut it off.  Use the block on the AC plug of whatever you are connecting the piano to. (i.e. amp, etc.). 

I should note here that this should be done AT YOUR OWN RISK.  If you have an electrical grounding problem *inside* either your piano or your amp, etc. you run the risk of shock by floating the safety ground.  For example, you may have a failed 'death cap' in your amp which will make the chassis live if it is not grounded.  Or, as cinnamon said, someone was monkeying around inside something and things are hooked up the wrong way somewhere.  The safety of your earth grounds should be checked before assuming floating ground is a safe thing to do.  But- one must also note that for decades tons of electronics and appliances were produced (and are still in use today) that do not have a safety ground (3rd prong).

A BETTER, and more proper way to address this issue is to use a direct box with a ground lift.  Or an isolation transformer, like the Whirlwind ISO1.  This way the safety grounds of all of your gear will still be properly attached to earth ground.  One must be careful with ISO transformers however--- if they are placed near a power transformer, motor, etc. the magnetic field may induce a hum in the ISO transformer itself, causing the same exact type of problem (hum/buzz in audio).  Usually relocating the ISO or turning it in a different direction in relation to the component generating the magnetic field can alleviate this issue.

Good luck!  and most importantly... BE CAREFUL!

Tim

On the Speaker cabinet, there are four 1/4" jacks on the side-
Two are labeled PREAMP OUT and the other two are POWER AMP IN.
Plug dummy 1/4" plugs into the two POWER AMP IN jacks and that will kill the signal going to the power amps.
Do not use long cables- they will pickup noise.  You can also just plug a short 1/4" cable in between the two POWER AMP IN jacks.
They are both inputs, so hooking them together is no problem.

You can then take the stereo output from the PREAMP OUT jacks to your recording console.

Or, you can plug a set of headphones in the Headphone jack and leave them on the floor next to the piano.

First, a response.  Second, my take on the Illdigger mods.

I guess it is unfortunate that all of our advances and years of technological development have led us here. 

By extension of some of the arguments being made, we might as well go back to wax cylinders.  It seems that even if one were to change one or two components from the original amp it might adversely affect the sound and hamper the musician's ability to be inspired.  How do we even know if a working, original amp still sounds today the way it did when it was new?  We don't, and should not use that as a guide.

The merits of playing a real mechanical/electro-mechanical instrument vs. playing a digital simulation or sample are not being argued here.  The real instrument is better from a musical experience- period.  Real instruments allow nuance and infinite resolution of dynamics.  If you hit a key really really hard on a Wurly, it will respond accordingly.  Often, the reed may even break.  On a digital simulation, it plays the sound for velocity 127.  You may hit the key even harder next time, but its still 127 to the computer.  Eventually the key will probably break off.   Of course-- real pianos sound better.  Real pipe organs sound better.  When the guitarist complains to me at the gig because I ask for help moving all these heavy old keyboards around I tell him when he replaces his guitar with an iPad I'll leave the heavy stuff home.

BUT, in order for the real instrument to do what it is supposed to, it must be properly maintained and set up.  If the piano must be in tune and sound good, a Nord can and will outperform a real Wurly if it is compared to a real piano that has not been maintained.  Same with a real piano.  Same with a real pipe organ.  Often this is the case, unfortunately, and the digital electronics win out.  And, in all fairness, some of the new stuff is quite excellent- despite it not being the real deal.

One of the most obvious examples of all this is a Rhodes Stage piano.  It doesn't have any active electronics.  Only 2 passive pots and a cap.  Depending on how it is set up, it can sound VASTLY different.  Thin, round, even, uneven, clanky, clinky,  barky, bell like, thunky, crappy dynamically, great dynamically, good sustain, poor sustain.  It's all in the setup.  The Wurly, although different, has many of the same properties due to the mechanics and setup.  Again, I will restate that the sound of each individual piano probably has more to do with the setup of the reeds, pickups, and action than an original amp (properly working) vs. a new amp.  The electronics either get the sound out of the piano or hide it beneath noise and artifacts.  Again, a properly operating vintage amp does not contribute appreciable distortion (unless pushed too hard- but then the speakers also contribute to the distortion) - but it is still NOISY regardless.  Hard clipping is hard clipping in the solid state world, and is generally considered offensive.

Sorry, but removing hissy noise and AC hum does not lessen a musician's experience, it improves it.  In our experience, not one client has ever wanted to go back to the original amp after hearing ours properly installed.  In the 10 year history of production, now with nearly 1000 amps in the field, we have only ever had one person return an amp to us for a refund, and that was without a clear reason.  If that one person didn't like the sound of our amp, which may be the case, then that person is the 0.1% outlier in our data set.  Of course, there are probably 1000s more out there that have not purchased our amp because they don't like it.  But perhaps they haven't heard one live in person, they bought a new amp from somewhere else and they are happy with it,  have heard an improper or poor installation, or tried it on a piano that was really bad.  Or maybe they have preconceptions or misconceptions about the sound- how it sounds, or how it should sound because it isn't an original stock factory amp.  Or maybe they just plain old don't like it.  Maybe they think it is too expensive.  That's fine, and, there are other options.  Everyone can do what they wish.  But I will always defend our product and our reputation if I feel it is being misrepresented or criticized unfairly. 

If a new amp or component or whatever is designed properly, it will not change the desired character of the sound.  It will only remove the undesirable side effects.  If a person likes side effects, stick with the original.  Can't help anyone here.  I don't think side effects are a musical source of inspiration, however, unless one likes timing their music with AC line frequency artifacts or puffing vibrato.  Maybe avant garde types?

As for the tricked out Wurly discussed having problems with noise on stage, there are various reasons why it might be noisy, even with a new amp, if it even has one.  We have never done a MIDI install on a Wurly, so it isn't our work.  There are 3-knobbers out there tied in to original 200A amps as well as other 3 knobbers that aren't ours.  Maybe a ground went open somewhere inside.  Maybe the MIDI system was creating hash and interference due to a failing power supply wall wart.  Maybe another connection came loose.  Maybe the volume pot was going bad.  Maybe the IEC inlet was busted and the ground was intermittent.  Maybe it didn't have reed bar shields.  Maybe the keyboard player left his cell phone on the top.  Who knows?  It wasn't right, but it could probably be properly resolved by someone with the right skill set.  If all the noise and interference was desirable, they wouldn't have asked to use a backup piano!

Backups are often needed for various reasons. Subs are generally kept on standby for quick swaps when things go south.   What if reeds break?  What if a key gets stuck?  What if the piano gets knocked over and lands upside down?  Rain at an outdoor show.  What if the original amp blows up?  What is the artist has a fit and wants a new piano because the guy running monitors wasn't looking?  LOCUSTS!!!!

Nothing is fool proof or bullet proof, but we'd like to take as much precaution and do whatever can be done to achieve the highest possible level of reliability.  Old electronics are one of the biggest failure points.

As for the Illdigger mods, here is basically what he is doing, quoted direct [sic], followed by (>>) my comments:

It should be noted that in this rebuild process, it appears that there are no changes to any component values from those originally specified.  So he isn't really modifying the design, but rather blueprinting it.  The only modification appears to be low noise transistor substitutions.

First, Mr. Illdigger's editorial:

1.  You can read all over the net that wurlitzers are noisy and you can't do anything about it. B.S !

>>  Agreed.  But there are limits to how far you can go with the original circuit and equipment.

2.  all you see on forums is people telling you to just replace the whole preamp/amp board with newly made ones. no offense to these people or the board makers but to me this is HERESY.

>>  Disagree, but we make and sell boards.  We are admittedly biased.  It must be considered also, however, that what is being proposed here by making improvements to the original equipment is also heresy to some.

3.  I personaly wouldn't want op-amps in my wurly.

>>  Disagree.  A properly designed circuit with a quality opamp SELECTED for the job can and does work better than the original Wurlitzer circuit.  Opamps are just great when used properly.  Any recorded audio we hear has likely already gone through 100s of opamps.  Anything used improperly will be bad.  Sadly a lot of audio equipment is also bad.

4. This is a good discrete transistor design and there's still a lot you can do to lower the noise further.

>> Not really a good design.  The front end isn't too bad- it is a marked improvement over the 200.  Overall it still has many weaknesses.  You can, however improve the noise.

5.  It's just that normal repair guys don't want to go through all that trouble or simply don't have the knowledge to do it.

>> True.  It is a lot of trouble. And some guys don't have the knowledge.

6.  Or they would have to charge too much because it's a big job.

>> Also true.  It takes many hours to do a rebuild cleanly and properly.  By the time you pay for labor and parts (especially some of the parts that have been chosen here), a new amp board will actually be less expensive, perform better, and have better long term reliability.  It is possible that once Mr. Illdigger does a few dozen rebuilds, and deals with cracked boards, improperly removed boards, improperly shipped boards, other flaky components and intermittent problems that start acting up AFTER he has rebuilt it and sent it back out, and flaky clients, he will likely start telling people to buy a new amp board.  Unless he really enjoys that sort of thing, which he honestly might.

And now the technical details, aside the normal repairs, clean up, and recapping he has discussed:

1. Replaced the transistors with modern low-noise ones (drasticaly reduce hiss)

>> Probably 2N5088s or BC550s.  These aren't particularly modern, but are solid performers.  There are many others...

2.  Replaced all signal carbon resistors with high quality film ones ( the red ones, in key spots, especialy the first ones, drasticaly reduces hiss.

>>  Absolutely, but the expensive resistors he is using are probably overkill in this application.  Any decent metal film will do- very accurate, and lower noise.  Thermal noise of all resistors, regardless of type, is the same.  There are other mechanisms for noise in different types of resistors with regards to construction and materials. 

The first resistors in the signal chain are the most important, because any noise they create will be amplified as the gain is highest from the input.  If it's along for the ride with the signal from the pickups, it will be amplified just as much.

For those that care, you can look up the theory and math. 
FWIW, carbon comps are among the noisiest.

3.  The combined effect of the new transistors and resistors is very noticable in lowering the background hiss).

>> Yes.

4.  replaced the electros with high quality Nichicons

>> Great.  Nichicon makes a great cap.

5.  All coupling caps replaced by high quality bipolar Nichicon muse capacitors.

>> Not sure there is a real advantage here.  The datasheet and technical specs for these audio caps are not much different than Nichicon's regular caps, except for flowery language like "Tighter bass".  Maybe they are lower ESR and ESL or have different dielectric absorption characteristics resulting in better frequency response.  It isn't obvious from the datasheets.  It may just be marketing to sell the same cap as their commercial line at a higher price to audio types.

6.  All the ceramic feedback caps were replace by film and polystyrene capacitors (for mojo!)

>> Probably not necessary, unless the ceramic caps are damaged or highly microphonic.  Yes, ceramic caps can be very microphonic.  'Mojo' is not a valid reason in my view, although others are likely to disagree.

7.  replaced the aux and driver transitors with low noise ones and matched the pair of drivers to fix the crossover distortion some wurly can have getting older.

>>  Yes.  Keep the signal path as clean as possible as we head downstream.  We'd also replace the gain trimmer (R-11) which gets flaky.  The crossover distortion definitely gets worse as the amp ages.  One of the weaknesses of this design- transistor parameters that drift start causing bad behavior.  Better designs avoid this from happening by designing around or compensating device characteristics that drift with time and temperature. The crossover distortion will likely creep back in after a while.

8.  replaced all the resistors in the bias/psu with higher wattage and matched where applicable. High quality Draloric 0.1% resistors for voltage reference and bias, to realy put back the wurly up to specs intended by the designer, and not the stock 20% resistors which can be up to 40% appart when they should match.

>>  Don't think any original resistors on a Wurly 200A board were as bad as 20% tolerance.  All I have ever seen was 5% or better, except for some 10% carbon comps on the HV supply where are not critical.  It is possible they drift out of tolerance further than their marked tolerance.  Not going to take the time to figure that out.  Replacing them can't hurt, but 0.1% tolerance is probably overkill.  The transistors vary more than those tight tolerances can likely account for.  But again, haven't done and won't do the analysis.

9.  brough the tremolo circuit back to spec, changed and matched the oscilator transistors and matched the resistors.

>> If it starts up quickly and oscillates at the right frequency and amplitude, no need to touch the oscillator.  But the trimmer that feeds the opto is usually flaky.  We would replace that.

10.  redid all the power wiring cleaner and with more rubust wire where needed

>> Cleaner absolutely.  Never thought the 18AWG wiring throughout the piano wasn't robust enough, however... the fuse blows at  1/2A.  If its the right fuse...

11. All signal cables redone with high quality shielded wires routed as far as possible from power cables. (this is realy key to reduce hum, a stock Wurly is full of problems)

>> Maybe if the original wiring is bad.  The original 200A audio wire has a foil shield with 100% coverage, can't get much better than that.  His final pics also show the original wiring in the audio path still in the piano and being used.

12.  The piano was now fully working and very low hiss but a bit of hum still remained low in the background. The stock Wurlitzer is grounded in way too many spots, through the cable shields, the harp etc. Which causes internal ground loops (HUMM..).

>> This is true.  Our 200A replacement amp comes with new ground wire and instructions for properly routing it using a different scheme.  The transformer, when *physically* inside or part of a ground loop will induce hum from the field it generates.  The loop with the transformer inside must be open.  The ground can be reconfigured around the transformer without affecting the integrity or safety of the ground.

13.  Instead of putting another neon bulb powered from the mains like the original, (Neon bulb induce noise in the circuit by themselves, plus the additional mains voltage in the wires which could induce humm in the audio) I replaced it with a big orange led powered from the psu.

>>  We've never had a problem with the neon bulb.  But if it is dim, flickering, missing, or blown we will often put an LED in its place and tap power from the amp board.  If the original is still good we will leave it in place and clean up the AC wiring.


That's a wrap!

Tim

Well there goes this whole thread...   

Disclaimer:  I am here trying to clear some things up with regards to this topic.  I will state that I am not a believer in audiophile fairy dust or the like.  I don't think there is magical mojo that can't be somehow explained in audio or that, for example, cloth covered wire sounds better than plastic covered wire. Electrons are electrons, and they move based on the laws of physics.  Yes, of course, some things sound better and some worse, and there are reasons for that- scientific, emotional, psychological.  I cannot explain one's emotions or the psychological aspects thereof, but the science and engineering can be explained and reproduced, provided the proper study and time is dedicated to a given subject.  Human hearing is excellent, no doubt, but that hearing changes with the time of day, one's state of mind, whether one has eaten, what influences one is under at a specific time, etc.  Please try to keep that variability in perspective when considering specific arguments as far as sound goes.

The image attached below is, in my view, quite a funny but true reflection from Ethan Winer.  If you haven't read his book, "The Audio Expert", you may want to consider taking a look...




"Do It Again" was recorded on a Pianet, not a Wurlitzer.  It was Fagen's rig at the time.

If that clip is being used as a reference to the 'original' Wurlitzer sound, I don't think the merits of this 'old' or 'original' sound can be argued from a position of strength when the correct instrument isn't even properly identified in the first place.

For those out there that use our replacement amplifier boards, Thank You!  They were created from a need to make the 200 usable and recordable in today's recording and performing environment.   I designed it in 2006 after trying to rebuild my own 200 amp and getting inferior results.  Feedback from Ken Rich helped us dial in the design so that it really sounded right and was easy to install.   The pros love them.  Finally the FOH and monitor engineers can relax about the Wurly.  No one is asking "Where's that darn hum coming from???"  although the language is usually more colorful...  And the recording engineers in the studio don't need to play 'tricks' to make the piano work in the mix.  No notch filters at line frequency or its harmonics.  No mixing in 'reverse phase' hum to cancel the hum that is there.  No noise gating.

The original 200 design is horrible.  The architecture of the circuitry - not even the parts -  makes it high noise.  The vibrato huffs and puffs.  Even putting military spec $10k gold plated parts won't make that design low noise.  OK- maybe a little lower, but still not low.  Why the heck did Wurlitzer have 5 versions of the original 200 amp if it wasn't a problem in the first place?  Why did they bother with the 200A if the 200 wasn't inferior?

It is true that original 200As can be stuffed with better parts to make them perform better with a lower noise floor.  Fortunately the noise levels are improved thanks to a better circuit architecture.  Mr. Illdigger happened to publish his findings in this instance.  Many others that figured this out years ago didn't.  200As are still unreliable, however, for other reasons- especially in the power amp stage.  We did the parts swap routine on original 200As for years before releasing the 200A amplifier.  The 200A was added to the lineup at the request of techs that wanted better performance and reliability, and also did not want to waste time working on original boards that were flaky to begin with.  i.e.- people who were sick of the BS, the emergency service calls, and constant need to go back in and fix something else.

I have heard lots of stories about things that were done to make Wurlis quiet back in the day - remoting the transformer, remoting the amp, removing the amp and using something else (phantom power, anyone?), adding foil shields, changing the amp, etc.  None of us really know how these things were set up or recorded, and under what conditions.  What mic did they use?  Was it direct, was it through another amp?  How was it EQed?  The list goes on and on...  It is all assumptions and guesswork on our part, unless there is someone who can verify the history of it all AND back it up with photos or some other original records. And memories are generally very foggy now- so maybe they can't even (or don't want to) remember....

As for the speakers, the original Wurly speakers absolutely sound better than any of the reissues out there.  They have the right sensitivity and frequency response, and work well with the 'cabinet' - i.e. lid and piano.  The problem is they dry out, crumble and tear.  Or they warp, and then you have voice coil rub.  There are not too many originals left working properly anymore.  Busted speakers were certainly not a part of the classic Wurly sound, since they weren't busted in 1972.

So, if you want a Wurly with speakers, you use what you can get.  As long as it actually fits...

The cost to actually reissue an original Wurlitzer spec 4x8 oval speaker is out of this world.  No one would want to pay for it.  Thus, we are left using what it already available and customizing the specs with simple manufacturing mods that are in a very narrow design space.  Basically voice coils and dust caps- that's it. If anyone out there can figure out how to actually reissue the 200 style alnicos, with the same frequency response and sensitivity as the originals (as well as the other essential Thiele/Small parameters), have it actually properly fit inside and mount in the piano, and do it at a reasonable cost, PLEASE DO IT!

The truth is, different pianos sound different MORE because of the way they are set up than the electronics (if the electronics are working properly).  The pickup alignment to the reeds is far more critical to an individual piano's sound than the electronics.  The original Wurly amps, with all of their noise and other undesirable behavior, have a certain frequency response.  If you build another amplifier with the same frequency response and input/output impedance characteristics, the piano will sound the same as far as its character goes.  Yes there are non-linearities tied to certain designs that can have an effect on the sound (this is the whole concept of distortion), but our testing and research has shown that these electronic non-linearities were not a dominant factor in the overall sound of the piano.  In addition Wurlitzer reeds changed dimensionally in their manufacturing throughout the lifetime of the instrument, which is also why different pianos from different eras sound different- not so much because of the electronics.

Just for the record, it isn't often I get up on a soapbox... but we have been dealing with all this Wurlitzer stuff long enough now that I can speak from a pretty strong position- and we have the data to back it up!

Thanks for listening,

Tim
retrolinear.com

Looks great Cinnamon!

We actually had our prototype knobs 3D printed about 4 years ago before committing to purchasing injection mold tooling.
However, the resolution and finish of 3D at that time was not quite as nice as it is now (ours had fine lines in it, like it was printed by an old dot matrix printer (rememebr those?).  I still have the prototypes somewhere...

The harder part of that whole project was actually getting the springs and the inlays made.  You can get cheap, or you can get good.  Rarely both.

We did the same for the lamp jewels also, we have them in original orange and clear- and the clips that hold them in too!

3D printing services are available in many places now, just Google it!

Hello,

If you decide to replace your amp, we hope you'd consider the Warneck Research EP200.

Our amp is a NEW design using high performance components for high reliability and a very low noise floor.  The preamp section has EQ to match the original Wurlitzer curve while eliminating all the undesirable behavior (hissing, puffy vibrato, etc.).  The power amp is protected against overloads and shorts, and will safely shut down in the event it is presented with a fault.  Reed bar shields are also included in the box to eliminate hum from the pickups.  We also offer a variable speed vibrato upgrade with a modulation waveform that exactly matches the original.

The other amps available are simply copies of the old original Wurlitzer 200 design, with very minor enhancements (fuses, terminal blocks, etc.) that do not really improve the noise floor, reliability, or power output.  Despite the similarity in looks, there is a large difference in performance.

This is why professional musicians, professional techs, and studios choose Warneck Research.

Best regards,
Tim

Designed for 5.5Hz, but may vary up to +/- 0.5Hz due to component tolerances.  This is in line with what the original amps produce.

If you want a custom fixed frequency, we can easily change it to whatever you want.

We designed the VariVib add on so that you can get a range of less than 1Hz to 15Hz while maintaining the identical amplitude modulation envelope on the audio across the entire frequency range. It sounds authentic (like Wurly vibrato should) other than the speed variation now available.

Best,
Tim

The Ian Fritz or Moog test circuits are good for small signal transistors in low power applications, but won't realistically work for power devices.

Unfortunately the Peak tester also will not realistically work well for power devices.

To get a good idea of matching for power devices, you need to put them in a circuit that powers them with lots of volts and amps- the region where the device normally operates.  No battery powered multimeter or mini-analyzer will do this.  For where those testers exercise the devices (very low power) you may be able to match them, and if you are lucky, that will also translate to matching at the higher power operating regions.  But, it is unlikely.  You will need to use a curve tracer with some real teeth (Tektronix 576) or build a custom power circuit with a big power supply to test for matching power devices.  The Rhodes amp module itself is the best tester you have, since it is actually the real application.  Careful exercising of the circuit through multiple operating conditions can give you the data you need to determine if the transistors are matched closely enough.

To sum it up:

Just because the car runs fine at 20mph doesn't mean it won't fall apart at 70mph.

Best
Tim

This can end up being a pretty deep discussion of electronics.

But, for the most common Rhodes pianos, here is the deal:

Peterson Preamp:
Matching does not really matter except for the vibrato oscillator transistors, to keep the vibrato even.  But even here it is not that critical since the Rs and Cs that make up the oscillator are more likely to have drifted or have wide tolerances.  The audio part of the circuit is single ended.  No matching necessary.

Janus Preamp:
No transistors to match.

Peterson Power Module:
Output Transistors *ideally* will be matched for both Vbe and Hfe.  But no basic multimeter will run them at real world currents to get useful measurements.  One would need to construct a test fixture or use a curve tracer to properly do it.  In lieu of that, installing two transistors in an amp module and powering on into a dummy load will give you an idea of the matching.  Usually new devices from the same lot or date code are close enough.  We look for a low DC offset on the amp output and fairly symmetric clipping just at the onset of clipping.  Again, into a dummy load.  If both DC offset and symmetry track well when the amp is cold and hot, the devices are matched well enough.  Again, here, we also depend on the tolerances of the bias resistors and driver transformer.

Janus Power Module:
Small signal transistors Q1 and Q3 should be ideally matched, but there is an offset adjust pot to trim DC offset.  So matching isn't that critical.
Having matched output devices would be also ideal, but again, with an offset adjust it can be nulled.  But you are adjusting the offset of the composite circuit, not just the input or output devices.  So one needs to look for symmetry and again stability over temperature, like in the Peterson circuit.   

Super Satellites:
Input Diff Pair (Q1 and Q2) would be nice to have matched.
Output devices (Q6, Q7) and predrivers (Q4, Q5) for low DC offset, but there are trimmers here too...
This amp design is not particularly good by today's standards- be careful subbing in modern power devices for the older, slower ones.  The amp may oscillate at HF and overheat.

Good luck,
Tim

Good to hear.  Those transistors are even tougher than the MJ15016s.  Not surprised you needed a little more bias at the lower supply voltage.  Hook it up to a dummy load that equals the speaker load impedance.  Then run it so that the output voltage peaks at about 63% of the supply for a good long time and get it good and hot to make sure it doesn't run away.  If it makes it you're golden.

Best
Tim

For DC offset:

Measure the DC output voltage between the amp output and ground without a load connected.  It is best to do this first anyway, to insure you don't fry your speakers after rebuilding the amp.  ALWAYS check the DC output voltage and make sure the amp passes a signal (preferably with a scope) properly first with no output load, then with a dummy load, before connecting to your speakers.  Much easier to do this than paying for replacement speakers or a recone (especially with the oddball 32 ohm suitcase speakers).

Since your piano may have a lower supply voltage than a suitcase, measure (don't trust the schematic) the power supply on your piano.  If it is +/- 30V rather than +/-40 you may need to listen (or scope) the output for crossover distortion while connected to a load when the amp is cold (right at power up).  Crossover distortion will decrease as the amp heats up, but you shouldn't have any when it starts out cold.

If you have crossover distortion, you may need to slightly increase both the 12 ohm resistors.  And I mean slightly- maybe 1 or 2 ohms AT MOST.  We have never needed to do this in practice, and we've rebuilt many Petersons, but we might in the future.  You never know.

Good luck with the project- but be careful- you can get hurt working on this stuff!

Well, it sounds like the bum note was a C above middle C, and those are usually unpainted hard black tips, so if it is a square tip piano that is easy not to notice visually as compared to the unpainted soft tips for the bass end.

Now you know the next time you hear it!

Every time I work on a Rhodes, I learn something new.  And often these compiled tricks and lessons bail me out of stinker problems I encounter as I continue to work on more pianos.

Redesign being needed is true for complex designs, but not for the simple Peterson output stage.

Increase the 2.7 ohm resistors to 12 ohms, 1W.
Change out the 820 ohm 2W to 820 ohm 3W (2W was marginal to begin with)
Replace the 0.5 ohm 5W sandblocks with new ones.  0.47 ohms are OK too.
Replace the Delcos with ON Semi MJ15016s.  These need to be somewhat matched, as long as the DC offset of the amp output without a load is 150mV or less you are OK.  Otherwise swap out one for another MJ15016 and recheck offset.  Usually within a batch of the same date code they are close enough- it is rare we need to swap them out.

With the 12 ohm bias resistors, you should not have any crossover distortion when cold.

So if you buy 4-5 MJ15016s to guarantee you get a close match and the resistors from Mouser you will be out about $30, and have a few spare transistors.

The MJ15016s are a 15A 120V part, so they have a much better SOA (safe operating area) compared to the original Delcos.  Simply put, they won't run away and catch fire like the Delcos often would.  Plus, the Delcos were only rated for 60V.  Part of the reason they eventually run away is because the Rhodes power supply runs at +/-40 to 43 VDC.  When the amp swings to drive the speakers when loud, the transistor not conducting can see more than 60V across it.  Each time this happens it like shooting the transistor with a BB.  Enough BBs, and the transistor dies.  In a Rhodes, this results in a catastrophic failure.

 

Wrong hammer tip?  Possibly wrong era tine with wrong strike point also.

Hello,

I feel like I should answer here as I designed the RetroLinear/Warneck Research EP200 amp.

First to answer the questions:  Yes, diodes D2 and D3  are reversed on the layout drawing.  Good catch.  D4 and D5 are also reversed in that drawing.  Somehow D1 made it though correctly.  Second, the two resistors in question were changed during production.  The final and correct values to use are 6.8k for R75 and 2.2k for R76.  If there is a 5uF cap in series with the wiper of the volume pot and the terminal post where R75 is soldered, replace it with a jumper as shown in the layout drawing provided above.

There is unfortunately very limited potential in your original amp. 

When I got my first 200 when in college, I bought all new premium quality parts to rebuild the amplifier.  I rebuilt it properly and carefully, doing everything right along the way.  When I flipped the switch, I still had a hissy hum bucket.  The vibrato would huff and puff, and the amp still didn't have considerable output power.  As I continued to study analog circuit design as I went onto graduate school in EE, I went back and looked at the 200 schematic to figure out why it was so bad.  It was then I realized the flaw- there was no way, based on the architecture of the circuit design that the amp could ever be low noise- no matter how many caps or premium transistors you put in there.   And the amp was designed to rely on characteristics of transistors that drift over time and temperature!  So that means that you could not expect consistent performance over the life of the amplifier.  Not a sound design, but the best they were doing at Wurlitzer in the early 70s.

From there, I did an analysis of the pickup structure in a Wurlitzer, and then designed and built a low noise amplifier that matched well with the pickups and had the necessary characteristics for excellent performance.  The vibrato feature was then added after I had a good preamp, and finally a redesigned power amp was put on the backend to drive the speakers.  Our EP200 amp was born.  Adding the comb pickup shield plates to the EP200 amp kit knocked the last bit of hum out of the piano.  Silence, unless you play a key.

You may want to consider that some companies sell parts and kits simply to make money from as many people as possible- and they do not have to provide technical support for the electronic parts they sell if you do the work yourself, since there is no guarantee that the parts get handled, soldered, or installed correctly.  Parts are sold at a considerable markup so that they can still make money from people who are not willing to commit to buying a new amp.  Everything is completely on you, and the improvements from many of these kits are usually marginal, insignificant, or non-existent. 

A careful look at the other amps available on the market will reveal that they are basically duplicates of the original Wurlitzer design, with fuses and higher power resistors added.  No change to the original failed circuit architecture!  One may also note that the other boards out there are starting to look more and more like our design (with solderless terminal blocks, etc.) but still with no change to the circuitry.

The original 200A had a much better preamp, but the power section still depended on transistor characteristics that drift.  No good, so we adapted our 200 design to work in 200As.  Our 200A amp provides significant improvement in the power section and still has an improved noise floor over the original 200A.

So, for $389 you get everything you need to make your Wurlitzer sound as good as it possibly can as far as the electronics go, pickup shield plates (for the EP200), no time invested in working with electronics except for the install, support from us if needed for the installation, a full 2 year warranty, and peace of mind for the next few decades.  Our amps are assembled and fully tested here at RetroLinear before they go out the door.  Many, many Wurlitzers you see on stage and in studios now have our boards in them- all working quietly, reliably, and bringing out the best each piano has to offer.

I think this is a pretty good deal for an instrument generally selling for $1000+ on the 'used as-is' market and only heading up from there. 

Here you can find several notable users of our products:

http://3knobwurly.com/artists.html

That's how they shipped from the factory.

Enjoy it, its a great year.

I guess we will need to rename this thread  Grommetgate. 

Hopefully you all will be pleased to know that yes, I stared at the same tables, consulted with people in the elastomer industry, and had testing done on original factory parts I bought in 1989.  We worked with our supplier and selected a compound with the right qualities and durometer, based off the original.  Even within a specific compound, there are several quality grades.  We selected a high quality grade compound, probably better than what Rhodes originally used, but I cannot say for sure for obvious reasons (I wouldn't even know who to ask, and they probably wouldn't remember anyway).  We may need to wait another 10-20 years to find out how the grommets hold up long term.  I can say that our grommets have been in production since about 2008, they are in my personal instrument that had pancaked original grommets, and as of 2016 they still look great and function as intended.  I doubt they will change appreciably in the next 5-10 years since they haven't changed yet.

If we didn't select the appropriate compound and durometer, it is unlikely voicing would even stay consistent on a given piano as the grommets would deform in a very short period.  This is why we had grommets made in the first place (during the Keyboard Cottage years) because *every* Rhodes supplier at the time was selling McMaster or McMaster style grommets. They were often sold with flat head screws and captive finishing washers in most cases (as was in the Mk V).  They NEVER fit properly and 2 hours after voicing the piano everything would be all over the place again.  Playing the piano would also cause voicing to drift!  I did not want pianos in the field doing this, so we decided to have grommets produced ourselves.  It wasn't long after we released ours that original looking grommets became available from other sources.

Yes our grommets are more expensive.  They are sourced here in the US, and made from high quality material.  The fit and finish is superior.  There are no deformities, flash, wrinkles, bubbles, etc.  All our grommets are consistent, and we provide a few extras just in case.

Our screws are custom produced with the correct shoulder to fit in the grommet properly.  Again, here in the US.  We opted not to have them nickel plated to keep the price lower, as it is not an externally visible part.  They are still plated, however, for rust and corrosion protection.  Quality thick flat washers, finished the same as our screws, were also chosen.

At RetroLinear we do our best to do things the right way and put the effort where it really counts.  This is why discerning clients keep returning to us.  Our instruments feel great, sound great, and our parts and electronics are very reliable.  And the end results are obvious, if you take the time to listen and compare.

Tim
retrolinear.com

Thank you Alan, you are right on the money.

There is no reason to switch out properly functioning vintage parts- the tips and dampers are part of the soul of the piano's sound. 

This piano is actually in decent shape- much better than many of the pianos that we see come into our shop!  The hammertips are barely worn.  The dampers appear to be in good enough shape to remain serviceable for a long time, with proper adjustment. 

Granted, there are times when things need replacement, but certainly not in this case.

Put in a new set of grommets and screws, and rather than spend $$ and time on parts that don't need to be replaced (and that may possibly change the sound of your piano), take your piano to a skilled tech have it tuned, voiced, and set up to play optimally.  Any good Rhodes tech will know that the original parts in this piano are in very good shape and will NOT try to sell you new parts that aren't needed.   If they do, find another tech!

Tim
retrolinear.com

Well done!

Can you plot frequency (x axis) on a log scale?  The curves will probably look more familiar and easier to read/understand. Most audio plots are loglog (both x and y) but you already did the log conversion for the y axis by calculating dB. If excel is going to be a pain, you can send me your data and I'll dump it in Matlab.

Best
Tim

For the record, I am also an EE with 15+ years experience doing custom analog and mixed signal IC (ASIC) design. I have designed many opamps, DACs, ADCs, sensor interfaces, and other analog circuits in bipolar, CMOS, and BiCMOS processes. I also have a lot of chips out there in the medical and automotive markets for companies like GE and Panasonic that are still in production. I know a fair amount about this subject- but I still learn something new every day- and hope to continue doing so.

Pnoboy responded before me but I agree with him on all counts.

I too would like to eventually measure the impedance characteristics and frequency response of a harp.

As he correctly stated, going direct off the harp is different than going to the stage tone and volume controls. I stated that with the 10k volume pot in circuit going out to an amp or booster with a 100k input would be negligible. This is because the 10k pot is dominant in loading the harp. The extra 100k would not change things considerably.

Pnoboy is also absolutely correct on the Janus input impedance. To be picky the series cap is also part of it- and causes a high pass response with a cutoff freq determined by the 10k resistor and harp output impedance- but it is probably not important at audio frequencies of interest. Because of virtual ground due to the opamp, the input impedance is 10k. The input current goes around the feedback loop- not into the opamp inputs.

Best regards,

Tim

Pnoboy is correct in his reasoning. The math doesn't lie. The 10k volume pot already sets the load on the harp. Anything an order of magnitude higher (100k) will have a negligible effect on a stage pianos level or frequency response. Unless, of course, you have an extremely long cable run or high capacitance cable, which is unlikely.  Even standard grade guitar cable (rapco, etc) is perfectly fine and won't introduce excessive capacitance in this application.

One could build a booster circuit with the correct components for $10 or less and an hour of time.  if done properly it would sound great and be low noise.

Sorry, but I am one of those people who believes everything in audio can be measured. Our test equipment is more accurate and sensitive than our ears. Our hearing perception can easily change if we are tired, hungry, etc. or even if we want to believe we are hearing something we want to hear.

A lot in the world of audio is specsmanship. But one must fully understand the conditions under which those specs were generated... And if they are really meaningful for your application.

The final suitcase preamp was designed by Paul Gagon.
He is now VP of Engineering at BBE Sound and G&L instruments.  A talented guy for sure.

The major difference in these versus the Haigler were the use of 5534s in the audio path for low noise. The stereo vibrato also has a unique feedback scheme using center tapped optos. In all earlier pres the intensity pot was in the audio path. In this design, the intensity pot directly varies the amplitude of the vibrato control signal. This then drives two opamp stages with feedback from the dual optos. One stage is inverting and the other isn't. With the feedback from the optos, the LED intensity is servoed in the LDRs to follow the vibrato lfo control voltage, controlling the amplitude of the two outputs. The entire circuit acts as a dual VCA of sorts, and its control voltage comes from the wiper of the intensity pot. It seemed Paul's goal was keeping as many pots out of the direct audio path as possible.


Best
Tim

It appears the MK2 preamp was modded in addition to the vibrato switch. 
Those caps in the front end and the resistor underneath are not from the factory.  They did not use components that looked like that.  You can also see that the soldering on those components is not factory (i.e. wave soldered).
I would expect that those mods on the front end are what is creating the differences in gain and frequency response. 
The apparent board rev has nothing to do with it.

If you put your Mk2 back the way the factory intended you will get the same sound as the Mk1 rail.

Best regards,
Tim
retrolinear.com

Hello,

Why don't you consider ordering a Warneck Research EP200 amp board for your 200?

They are a significant upgrade in performance and reliability (lower noise, better efficiency, output protection) and we have them in stock!
Countless touring pros and other techs use our boards get the best out of their pianos.

The EP200 even includes the pickup shield plates as part of the package.

http://www.retrolinear.com/web-store/wurlitzer-replacement-parts.aspx

Order online from our website or give us a call tomorrow- We'd be happy to chat with you to explain the benefits of our board.
215-699-8000

Best regards,
Tim
retrolinear.com

On the SuperSite:

Check the bottom of the page.

http://www.fenderrhodes.com/service/manual.html


All the best
Tim
retrolinear.com

Hi Justin

It sounds like there is something shorting out your pickups. This can be very
hard to see and/or find but once you find it the problem will be eliminated.

It is likely a small piece of solder hanging off one if the reeds or some other foreign material between one if the reeds and the pickup. It may also be a misaligned reed. I would remove the bass and treble damper assemblies and then carefully inspect the reeds and pickups, making sure the reeds are perfectly centered in the pickup slots. Then you can use a strip of paper and slide it between each side of each reed and the pickup to hopefully dislodge anything that shouldn't be there. Then blowout the pickups and reeds with compressed air. We use an air compressor as canned air usually does not have enough oomph.

To aid in your troubleshooting you can disconnect either the bass or treble pickup where the rca cable's positive lead connects to the pickup. Leave the grounds from the rca connected. This way you'll know what side of the piano the problem is coming from.

Finally check all your dampers. There should not be any stray bits of solder or other material on the bottom of the damper felts that  could potentially short between the reed or pickup. This is rare but it does happen on occasion.

Please let us know if you have further questions or concerns.

Tim
Retrolinear.com

Why not save yourself hours of frustration, the ordering and cost of non-returnable parts (+s/h every time you need something else), and poor, noisy performance even after the repair is done?

Just put in a new Warneck Research EP200 and have worry free ultra low noise performance for the long haul. Reed bar pickup shield plates are included with the EP200 package for even better overall performance.

Heck, I'll even send you a new fuse!   

Tim
Retrolinear.com

Hi,

It is likely you have 2 separate problems:

1.  Neon Light:  It is going bad or there is a bad connection.  Replace it or make sure it is properly soldered to the AC terminal strip.  We have replacements.

2.  Speakers: There is probably something wrong with your speaker and/or headphone wiring in the piano.  If the Aux out is working and you can vary the volume using the volume pot (make sure the switch on the amp is set to VAR) the volume pot is fine. 
In the 200A the speaker wires often get pinched and damaged in the process of opening and closing the case because they are attached to the speakers on the lid.    The headphone jack can go bad as well, causing lack of connection to the speakers when nothing is plugged in.  BUT- if you don't have a signal through headphones when plugged in, something is probably wrong with the wiring from the amp to the headphone jack.  The amp's output goes to the headphone jack and then from the jack to the speakers.  To test your speakers, use test clips on one of the speakers terminals and directly connect to the amp board SPKR OUT.  Disconnect any other wires in the piano from the SPKR OUT block. You may need a few scrap pieces of wire to go into the terminal block on the amp- test clips won't fit.  The power amp output is fault protected, so it is unlikely you will blow it out.

Let us know what you find.

Tim
retrolinear.com

Hi,

PM me your mailing address and I'll throw one in the mail.  We have a whole bag of them.  We actually also have an insertion tool for them, but if you are careful you can tap it into position with a hammer.

Best,
Tim
retrolinear.com

We use a heat gun with a narrow nozzle so as not to ruin the appearance of the hammer.  It also allows the whole area to be heated more uniformly.

Tim
retrolinear.com

Or RetroLinear?


http://ep-forum.com/smf/index.php?topic=7226.0


They are really, really nice...

As ever,
Tim

You can do the R28 mod as a simple place to start and see if it helps.  We have had to sometimes modify the overall gain of the preamp stage in the pedal by changing some resistors to handle a higher input signal without clipping the phasing stages.

There are several different versions of MXR Phase 90s with different amounts of ICs (single/dual opamps, etc.) and components (some are even now surface mount) so we generally figure out what to do on the fly based on what is in front of us.  All versions of the P90 circuits are basically or mostly the same (except mainly for R28 as you pointed out, LEDs, and DC power jacks), but they changed how they built them over the years.

Block logo, script logo, custom shop, EVH version...
Its all marketing, folks!

Tim
retrolinear.com

Yes this is normal for a stock Phase 90.  It needs to be modded to handle a Rhodes without distorting.

Tim
Retrolinear.com

You will notice that the transition point you are mentioning is exactly where the hammertips also change from soft black to red (if your piano was not modified).

The height of the hammertips changes here as well.  If the height of the hammertip increases by a step, the strike point moves back towards the player by a step as well.  In a piano with graduated height hammertips, the strikeline changes at each breakpoint in the hammer height (as well as the escapement).

Welcome to late Rhodes production optimization (actually it started a little earlier, but really became noticeable in '76 when the angled tips came into fashion). 

In pianos from the early 70s, all the hammertips were basically the same height.  The escapement was set by shimming the bass end higher than the treble end.  You had a linear gradation of escapement from bass to treble.  The strikeline was then set, and viola, you had a good sounding instrument or great instrument with proper voicing.  The shimming and strikeline setup was time consuming and took someone who had an ear and an understanding of the instrument to properly align.  You also had to then make individual adjustments to all of the dampers to get proper response and stopping.  The mysterious Buz Watson was particularly good at this.

Later, to save time on the production line they shimmed the bass and treble ends identically, and used the changes in hammertip height to save having to shim for escapement.  In fact, in most MK2s, they never even set individual strikelines- just bolted the pianos together using the pre-punched holes in the harp endblocks. 

With all these factors at play it was now impossible to get a linear strikeline across the piano, because the strikeline shifted in steps for each increase in hammer height.  HOWEVER- in most pianos, you could find a sweet spot that was 'good enough' for all ranges of the piano.  They may not have been optimal, but they were good enough to get the pianos out of the factory, quickly... without shimming and without messing with dampers too much.  Big time savings, big labor savings, and ears and understanding of the instrument was not as necessary to get them out the door.

Some pianos are more stubborn than others, and the point at which the whole piano plays evenly is still far off from optimal- the sweet spot for strikeline just isn't good enough.  Moving the harp one way makes the treble sound great, and the bass thunk.  The other way makes the bass sound great and the treble clanky.   Or (at least in my case), the tech is more stubborn, and wants excellent, optimal response in all ranges of the piano.  The only way to get this ideal setup is by having a linear strikeline, and this means either hammertips that are the same height across the keyboard with appropriate shimming of the harp for escapement, or equal harp shimming on both sides with a linear increase in hammertip height for each  individual note from left to right for proper escapement (a real pain and not a realistic way to approach the problem).

And you will occasionally find shims in later pianos etc. etc. but it was more the exception than the norm- and probably last ditch efforts to get a 'good enough' piano leaving the factory.  Remember you've got tolerance stacking:

1. Endblock punching tolerance and shim thickness tolerance.
2. Harp metal frame punching and alignment tolerance.
3. Tine 'pinblock' registration and alignment into the metal harp frame.
4. Tine pinblock curvature and cut tolerance.
5. Tine swaging taper tolerance.
6. Tine metallurgy, processing, etc. from lot to lot...
7.  Hammertiip height and shape tolerance...

The list goes on and on- and we haven't even addressed keybed and action issues.
A mouthful, I know... and that is just the tip of the iceberg...

So, what do you do? 

1. Live with a less than optimal piano that is acceptable in all ranges but not as great as it could be.
2. Try also shifting the treble end with the possibility of drilling new holes in the treble endblock.
3. Angle the harp on the bass or treble or both ends front to back by using a wedge shaped shim.
4. Get all your hammertips to the same height, shim the ends for proper escapement, and set an optimal linear strikeline.  This will also require significant damper adjustments.
5. Bring it to us, and let us deal with it.

Again, not all pianos are uncooperative.  Sometimes the sweet spot for the tines across the piano is wide enough that you can get an optimal response with graduated height hammertips and even shims without all the nonsense.  You can have a great sounding and responsive piano with just a few optimizations.  Most times they are not-- there are a lot of variables at play.

Hopefully this helps shed some light on the issues...

Tim
retrolinear.com

Try going direct from the RCA jack on the harp.  If the piano now sounds at the correct volume, you may have a problem with your passive controls, cable between the harp and controls, or RCA plug.

If it is still very soft, you may have a problem with the RCA jack, your pickups, the pickup wiring, or grounding on that side of the equation.

Let us know what you find out.

Happy New Year,
Tim

Hi RandomGruve,

If you get hum with the piano off, you have a ground loop.  The loop is through the piano's 3rd prong safety ground on the AC plug and your amp's 3rd prong ground (ground path 1) as well as the signal cable (ground path 2).  The Aux out jacks in 200s are usually metal and grounded to the piano amp rail, which is also directly wired to 3rd prong safety ground via the sheet metal chassis.  In later Wurlitzers (200As) they used a sleeved 1/4" jack to allow the audio out ground to be tied back at the amp board to help reduce the hum. 

Your other instruments will not have this problem if they are passive or not safety grounded to the AC line, since the only ground connection between your amp and the instrument is via the signal cable.  Ground loops are funny, but there is a clear way to troubleshoot and eliminate them if you are familiar with the problem.

You can verify this by floating the piano's ground temporarily by using a 3 prong to 2 prong cheater adapter.  If you float the piano's ground, and the hum goes away, the ground loop is verified.  You can also verify this if you don't have a cheater adapter by leaving the piano off and just pulling the piano's AC cord out of the wall while your amp is on.  The hum should go away. 

You may also still have the cap that goes from the AC line to chassis ground in your Vibrolux and it may be exacerbating the issue.  First try the polarity switch on the back of your amp.  Even better, have someone qualified remove the cap from your amp.  By today's standards, it is no longer considered safe unless it is a special kind of cap and you can guarantee that the amp will always be properly grounded in use.  Not possible if you play out in clubs and bars.

I don't recommend keeping anything floating from ground as it may present a safety risk.  This is why pros, in practice, in the stage and studio use direct boxes and isolation transformers to eliminate ground loops and hum, while still ensuring safety.

Please call us next week if you'd like to further discuss the issue.  We are closed for the New Year's holiday, but may have a few additional ideas for you. 

Happy New Year,
Tim
retrolinear.com

Our amps can take all the possible Wurlitzer speaker combinations, don't worry. 
Some added benefits of our amps which we don't advertise is that they are overload protected and over temperature protected.  In the event there is a failure, they shut down or throttle back so that nothing gets destroyed.  After the fault is cleared, they reset.  And there are no fuses to worry about! 

Several factors contribute to overall perceived volume. 

A lower impedance speaker will carry more current for a given voltage applied across it.  While this may electrically consume more power, depending on the design of the speaker, its magnet, its voice coil, cone, spider, etc. this may or may not end up being louder in actuality.
All of this is basically and roughly wrapped into a parameter called sensitivity-- which is how many dB a speaker produces at a given frequency (usually 1kHz) with 1W of power being used at a 1 meter distance.   The higher the sensitivity, the louder a speaker is with 1 watt going through it.

The speaker cabinet matters as well.  206s are usually described as sounding fuller-- the bass response is better from the larger cabinet but its treble response isn't, because of the larger speakers and the fact that the sound comes out at your knees.  The fullness of sound can be perceived as an increase in loudness.  Don't know for absolute sure, however, because I never measured it.

Finally, our hearing is non-linear.  We are more sensitive to certain frequency ranges and less sensitive to others.  Within those ranges, we hear differences in volumes differently.  You can learn more about this by studying Fletcher-Munson curves.

Tim

PM'ed

Actually they used the black plastic "F" caps on the 90 deg. 1/4" plugs for the speakers in the post 1977 speaker bottoms until the end of production in the 80s.

Remember that although Rhodes was a brand, Fender, Rogers and Rhodes were all under CBS.  There was a lot of sharing of parts across the brands.

I think CBS jettisoned the individual brands sometime in the mid 80s.

Tim
retrolinear.com