Messages

Good catch, Peter.

Duh.  I missed the part where OP specifically said they were plastic pins.  My bad.

Sean

Oh I guess I left out the part about how you might have to rebuild the areas of the front rail that are broken.  Cut out the sections with saw, chisel, or router, then glue in a block of maple.  I know that doesn't sound fun.

Sean

You should be able to buy new front rail pins online. 

Call vandaking.  https://www.vandaking.com/maintenance.html

   or call these guys  https://www.howardpianoindustries.com/piano-front-rail-pins

You might have to double check that they are the same size, so get your dial calipers out.

Sean

If the mdf shims were there before, you will need to replace them.

Off the rail - I mean the measurement from the underside of the end of the tonebar to the top wood surface of the tonebar rail.

Don't set the key dip.  The key dip is determined by the stop-lock position of the hammer cam.  There is no need for any felts under the keys around the front pins.  What you should set is the key height by installing felts and shims around the balance rail pins.

I think you could indeed get close enough with the felts loose and unglued.  The placement of the bumps is important for the miracle mod (obviously).  Get the key height even before you do that.  But I agree, it isn't like they are going to move a huge amount.

Every single year of Rhodes should have the squiggly black wire running along the pickup rail from end to end.  However, it seems to me that it would be possible to rely on the foil tape connection that runs underneath the pickup tangs.  Try it, if you are tempted.  However, the copper wire was preferred by the factory, so maybe you should go that way too.

Sean

The way it is done is usually, adjust this, adjust that, then re-adjust the first thing, etc.

You may not need any shims on the harp supports.  However, if the escapement is way off from having the tonebars 3/8" off the rail, then add shims on the harp supports.

I think if I were you, then I would get the felts back on the pedestals (miracle mod later), and get the keys in, and make a first go at the balance rail shims.  Well, maybe do the miracle mod now, without the harp installed.  I guess you could do that.

Then you will want the tines and harp installed.  Just flop it on, and hope for the best.  Do an attempt at getting the strike line correct (but it is very easy to adjust later to perfection).  Spend a lot of time getting the escapement and timbre set.  This means you will have to do a rudimentary job of setting the pickup distance and tighten them down, then fiddle with escapement and timbre.  Start with all the tonebars 3/8" off the top of the rail, and adjust as needed.  If you find that you are setting your tonebars all 1/2" off the rail, then install shims on top of the harp supports.  As you go along, you might notice that your pickups need to come closer, or go further back.  Adjust them as you go along with the timbre setting, or do it all at the end.  Well, you are going to end up making adjustments to the pickup distance at the end anyway so that you get each note sounding equally loud.

Fiddle with the strike line again to see if you really missed the sweet spot.

Then sleep on it and attack the dampers when you are good and rested.

You will realize that you can't simply do all this in one pre-defined order.  You kind of have to get it close and then make fine adjustments.  There is not any danger in doing it in the wrong order, because your time is free.  Readjustments are expected.

Good luck with it, and keep us posted.  Share some photos too.

Sean

1.  Yes, it appears that both amp modules are working.
2.  Shouldn't the Peterson have the effects loop in the speaker cabinet?  Some did.

Sean

I am surprised that your 1975 Rhodes has wooden hammers.  For that reason alone, keep it.  I thought the wooden hammers disappeared in 1974.  Does your 1975 piano have individual dampers, or damper modules (twelve dampers per module)?

Sean

Switch Lug C1 gets the signal from pickup F33, and acts as the hot wire of the split treble section.
Switch Lug C2 gets the signal from pickup E32, and acts as the ground wire of the split bass section.
Switch Lug B2 gets the signal from pickup E8, and acts as the hot wire for the whole harp, and also the hot wire for the split bass section.


If I had a 54-key stage piano that was not wired in groups-of-threes, I would LEAVE IT ALONE.  Changing the wiring on the pickup rail provides a great opportunity to ruin pickups.  If you heat the terminals too much, they will fall out of the pickup bobbin.  (Though I wonder if this can be repaired with the plastic-friendly variety of super glue.)

Sean

I think it is good old Baltic Birch plywood.

The Russians were making it with thinner plys than American plywood, so the imported plywood has more layers.  It was available with zero voids, so knots and holes would be filled.

Make sure that your 54-key Rhodes is wired in groups-of-threes, because many were not.

I think it is curious to want to split the harp, but immediately re-combine it through a pan pot.  If you do, you will have to tinker around to find a pot value that works well, and it may turn out to be less than wonderful. 

If I were you, I would split the harp and then run the two outputs into a cheapie mixer.  That way you will get full control, and should find a balance that works musically.  A Mackie Mix8 only costs $100, and the cheap cruddy mixers that sell for $35 actually do work well.  (I use a tiny LZSIG LMIX1 mixer with three stereo keyboards.)

For question #2, I am stumped.  Maybe I don't understand the question.  Try to keep it to two outputs by having the whole-harp output be the same connector as the upper-split output.

Can you show us a photo of the pickup rail wiring in your 54?

Sean

Replacing the grommets will make a big difference.  You will get a big change in sound and more sustain.

The grommets from McMaster-Carr work fine too.

https://ep-forum.com/smf/index.php?topic=9776.msg54209#msg54209


Sean

I dunno if Advent home stereo speakers are gonna have the punchy low end to do the Rhodes right.  But I agree they would look cute.

I would think you would have better luck with a pair of powered speakers.  Mackie Thrash or Thump 212 are probably a good fit.  You could also go to your local music store to audition the speakers (either bring your Rhodes, or just use whatever keyboard they have on display).

Plus, if you get a pair of powered speakers, you can use them for all kinds of other purposes... gigs, house parties, rehearsals, etc.

Sean

Oh wait.  You are in the UK.  Go to https://www.mouser.co.uk or try Farnell.

Yes, you can use plain-old potentiometers.

You might be able to get pots with the exact right-angle solder-pin connection that you need.  I can't get to my Janus preamp right now to look for myself, but there are lots of pot styles sold at Digikey, Mouser, Tayda, etc.

Oops.  Maybe you won't find the right pinouts.  Digikey only stocks three C100K pots.
They stock more than 150 different B50K (50K linear) pots.
Ouch they have zero C25K pots in stock. 

Aaah!  Good.  Mouser has them in stock.  Go to mouser.com.


Sean

I think if you wired them all in series, you would lose the treble, and it might sound tubby.  Plus, putting MORE resistance in series with each pickup might decrease the output of each individual pickup.

I would try groups-of-six instead of groups-of-threes.  There is a sweet spot:  if you have too many in a group, the output is reduced because of all the other pickups in the group create an escape route for the current in the pickup making the sound.  Groups-of-six work fine in a Rhodes. 

Do you have room to add a second magnet?  Or can you get stronger magnets?

Have you tried making a pickup with lower DC resistance?  Wind it with thicker wire?
Have you tried more windings (higher resistance, but more turns gives more current)?

I bet the simplest solution is simply a little more gain at the preamp.
----- -----

Oh wait!  Here is another idea from my history of harp splitting:  split the pickup rail in half, and send each half to a simple mixer.  I got more volume from the harp when it is cut in half, so it might work for you.

It would be easy to test, just short out half the harp with an alligator clip lead.  The remaining part of the harp should be slightly louder than before.


In any case, your clavichord looks insanely beautiful.

Sean

How about some photos of the pickups?

If it is wired with that horrific criss-cross patern, then look for touching wires.

If it is wired normally, in groups-of-threes, then use your multimeter to search for a bad group, or bad pickup.
See https://ep-forum.com/smf/index.php?topic=9989.msg55589#msg55589

Using clip-leads to short out large sections of the pickup rail can narrow down your search for the problem.  (If you short across a section of pickups, and your audio comes back, then you know that the problem is in the section that you bypassed.)

I don't suspect the name rail controls, but it is pretty easy to eliminate them from the circuit by plugging your amp in to the RCA connector on the pickup rail. 
----- -----

Now, you might want to sit down for this:  are your pickups wrapped with white tape?  White-taped pickups are often maligned, but probably deserve their bad reputation.  Get a bright flashlight, and look closely at the connections of the pickup windings to the solder-lugs on each pickup.  Search for a tiny hint of green corrosion of the copper conductor.

Study this photograph:


Sean

Oh, BTW, I think that if that is the marcel curve, it is really subtle.

Compare it to the second photo here:
https://www.vintagevibe.com/products/fender-rhodes-key-curved-marcel-pedestal

In any case, you can still install the miracle mod on those key pedestals.

Read all of Ben's Miracle Mod Bible and the related discussion:
https://ep-forum.com/smf/index.php?topic=4666.0

And also see this comment about Miracle-Mod-on-Marcel:
https://ep-forum.com/smf/index.php?topic=4666.msg44658#msg44658

Sean

Okay, step 1 is to order new grommets.  When they finally arrive, you can start removing the tonebars.

I would clean the tonebars with soap and water, or just wipe them with a wet rag.  I would not suggest digging in to the chromate covering.  If you are insanely rich, you can send them out to have them acid cleaned and re-plated or painted (it is not really that expensive).  The minor rust and zinc oxides are a nuisance, but they don't matter in the sound.

The tines themselves can be cleaned and polished to your heart's content with steel wool, brillo pads, or just oil or WD-40.  (Don't do this anywhere near the piano.)  I would pull off the tuning spring, and get most of the rust off.  When you are done, make sure you give the tines a wipedown with rust-protective oil.  I have used cooking oil sometimes.  I don't like WD-40 for this, because I am afraid it will damage the hammer-tips.  After you get the oil on the tine, wipe it off.  Wipe it off again, until it feels dry.

The tuning springs can be cleaned in your daughter's ultrasonic jewelry cleaner.  Dry and oil them lightly to discourage rust.

The only pain about this process is that you have to re-tune every single tine.  Ugh, so if the rust on the tines is not bad, you can skip removing the tuning spring.

I think replacement tuning springs are still stupidly expensive, right? A dollar each?  No thanks.

The good thing about this process is that you will replace the grommets at the same time.  That will be a huge improvement in the tone.

Also, when you are bolting the tine back onto the tonebar, I suggest that you put the tine block in your bench vise, and then turning the wrench tight while holding a finger on the tip of the tonebar to keep it aligned with the tine. 

Look out for rogue tonebars that have been accidentally bent where they twist.  Make sure the free end of the tonebar is lined up perfectly with the mounting holes at the other end of the tonebar.

That's all I can think of here.

Sean

I suggest buying the powered PA speakers, because you can get double-duty out of them.  They can work at home, and they can work at a gig.

I think that when you start looking at the price and the size and weight of the speakers, you will choose either 10" or 12" woofer diameter.  Most of the Rhodes cabinets had 12" speakers.  Keep in mind that the suitcase speaker drivers were very close together, so you will get a very different aural experience depending on how far you separate your powered speakers.

You also can experiment with the variety of tremolo, chorus, ping-pong, and vibrato effects units too.

Sounds like fun.

Sean

You should be able to sneak the bump in there even on those sloped-front key pedestals.  But I agree that it might be perilously close to the slope.  Lots of experimentation and fiddling, I suppose.

For encouragement, see https://www.youtube.com/watch?v=4keFGrcQSwQ

Sean


Also, I had always wondered if the action was placed too far back, but I sold my 1973 Rhodes.  So now I can't experiment with that.

Milo - You are awesome for posting this!

This should probably be a sticky post at the top of the category.

Sean

Don't modify the keys, pedestals, nor hammers.

You need to sit in the corner and think about what you did.  No TV for a week.

I fear that you might have gotten the keybed out-of-square.  It shouldn't flex, but it can... it is old.
(I am old, but I cannot flex.)  So check the keybed to see if one of the mounting screws pulled it out of square, or if one of the mounting screws is bent, or if the keybed is not sitting flat.

You must swear that you have never dropped the piano on one end, nor ever stored it in the closet on one end.

Anyway, you must figure out what changed a tiny bit when you did the recent maintenance.

In the 1976 Mark 1, you might still have a wooden action rail. But I really don't think you do, I think when they switched to all-plastic hammers in 1974, they also switched the action rail to extruded aluminum, and the harp supports are aluminum as well.

So if you have a metal action rail, then your hammer flanges are mounted in groups-of-twelve (as a "hammer comb").  These are screwed into the action rail, and they might slightly move a tiny bit if you loosened it up, and shoved it and held it to the left while you tighten it up. You can move them octave-by-octave.  I think this is the most-likely fix.

Also, the metal harp supports are mounted to the keybed with slotted holes in the harp support.  Unscrew the four nuts, then you can slide the whole harp (and action rail) to the left.  But this does not allow you to adjust the left side without moving the right side.  It should only take a few hours of fiddling until you find the sweet spot.

You should also verify that the action rail is still tightly attached to the harp supports.
----- -----

If you still have a wooden action rail, then the hammer flanges are individually screwed down to the action rail.  I don't recommend unscrewing the hammer flanges.  They break very easily.  Adjustments are hard, and only small changes are easily made.  Usually the screws that hold the action rail to the keybed are pretty hard to get wrong - but you might get lucky by loosening the screws and nudging the action rail to the left.

There is also the chance that you put a huge shim on top of one harp support (or removed one), but I think you would have mentioned that.

I can't think of any other possibilities.

Sean

I meant to say C14 connector, not C20.  I have fixed that in my post above.

I strongly recommend that you replace the input socket with a modern C14 receptacle.  Then you can use any old computer power cord no matter where you are.

It is not expensive, and it will only take half of your afternoon.  Any subsequent owner will be happy you made the change.

Sean

You mean you will mount the contact strip and the key contact board under that, and somehow have the Rhodes action press down on the contact strip bubbles?  So you will also be adding the guts of the fatar that turns these key contacts into MIDI messages.

You might be able to stuff it in there between the balance rail and the front pins.  You would have to mount it close to the balance rail, so that it will be under the black keys.

But will it still feel like a Rhodes?  Will it still throw the hammers up to the tines while triggering the physically interfering MIDI mush buttons?  Dunno.  Will you be able to adjust the setup so that the MIDI velocity is anything close to what you expect?  Maybe.

Will you somehow save money?  No.  No way.  Will it be fun?  Yes.  Will you look like a rock star if you pull it off, and it works?  Yes, absolutely.

Get some test parts here:  https://syntaur.com/keyboard.php?keyboard=Studiologic%2FFatar_SL-161

Good luck,

Sean

See my ancient history at https://ep-forum.com/smf/index.php?topic=4730.msg52770#msg52770

Looks like your mod isn't switched, right?  Take a look at my diagram, and this is what you want to do:

Remove the wire that comes off the harp somewhere in the middle.  In my diagram, the split is between E32 and F33.  Clip the wire off, and then replace it with a jumper.  In my diagram, the jumper would go on the BACK terminal of E32 and F33, exactly where the split wires were connected.  Be as gentle as you can be with your soldering iron - if you overheat the lugs, they will melt out of the nylon pickup bobbin.  Also make sure that the tiny winding wires of each pickup are still connected to each lug.  Hey - I got an idea... you could simply cut the split wires off about an inch away from each lug, and then solder them together.  That way you wouldn't have to re-heat the connections on or near the pickup terminal lugs.

So then rip out the cable that goes up to the second jack that was blasted into your name plate.  Obviously, remove that jack and the volume pot. 

Order a new faceplate from VV:  https://www.vintagevibe.com/products/stage-piano-name-plate


Sean

No no no no no!

Buy it!  You will learn to love it!

Yes, the Rhodes action is nothing like a real acoustic piano.  But it will infect you.  You will become addicted. 

Don't miss out on a good condition instrument at a reasonable price.  If you somehow can't make love with it, you can always resell it.

And after you sell it, you will regret it.

Sean

There are three different Janus preamps:
Schematic for Janus preamp with sliders: https://www.fenderrhodes.com/org/manual/fig11-1.jpg
Schematic for Janus preamp with sliders, version 2: http://www.fenderrhodes.com/pdf/late-mark1-suitcase-janus1.pdf
Schematic for Janus preamp with five knobs: http://www.fenderrhodes.com/pdf/late-mark2-suitcase.pdf


(Fixed broken link.)

I don't think I would like an organ-type action for the Rhodes.

You will want a hammer action.  However, I would rather deal with a "weighted" action than a super-heavy Yamaha action for the Rhodes.  Roland FP10 flimsy action might be just right.  But only your fingers will know for sure - go play them at ye olde music store.



I haven't touched the Roland V-Stage, but one NAMM-responder posted a video that asked why not just get a Fantom.  This guy:  https://www.youtube.com/watch?v=YBV2Lp3PRDY

Great.  With MIDI, you can trigger your DX7 samples.


Groan...

Very good.  With 400 hands, you can get lots of alligator clips working.

Please read this:  https://ep-forum.com/smf/index.php?topic=4641.msg22547#msg22547 
(Oh Goodness, that post is sixteen years old!)

Specifically for pickup stuff, see this:  https://ep-forum.com/smf/index.php?topic=7116.msg36655#msg36655
I think it says pretty much the same thing as:  https://ep-forum.com/smf/index.php?topic=3839.msg17262#msg17262

You should also read the service manual a few dozen times, this link works:  https://www.fenderrhodes.com/service/manual.html
Vintage Vibe has a pretty clean pdf version at https://cdn.shopify.com/s/files/1/0666/2821/files/Rhodes_Manual.pdf?6596484715058753348
----- -----

Your tremolo unit is the Janus preamp.  Very simple circuit, but there are three versions of that preamp: (I have the five knob version.)

Yours should match one of these schematics:
Schematic for Janus preamp with sliders: https://www.fenderrhodes.com/org/manual/fig11-1.jpg
Schematic for Janus preamp with sliders, version 2: http://www.fenderrhodes.com/pdf/late-mark1-suitcase-janus1.pdf
Schematic for Janus preamp with five knobs: http://www.fenderrhodes.com/pdf/late-mark2-suitcase.pdf

See also https://www.fenderrhodes.com/service/amp-diffs.html

For testing, you can power the Janus preamp with a pair of 9V batteries.  Or you can use your suitcase cabinet with the five-pin cable, and all that.  Or you can build your own: 
https://ep-forum.com/smf/index.php?topic=9706.msg53682#msg53682
https://ep-forum.com/smf/index.php?topic=9657.0

Don't build your own.

Sean

Oops.  Sorry I haven't been paying attention this year.  To answer the Cosmic questions:

1.  When the pedal is under the piano with the push-rod in place, the rear end of the pedal lever will be pinned down, and the front of the pedal will rise up as expected.

2.  The push rod adjusts by sliding the inner rod within the outer tube, however, when you get it to the perfect length, you tighten the wingnut to pin them both together.  With the "clutch" tighened up like this, the rod does not change length at all.  When you step on the pedal, the rod acts as one solid piece and pushes up on the sustain mechanism inside the piano.

3.  You do not have to tap any threads on the rod or the tube.  The rod slides loosely through the clutch and the tube, and only locks in place when the wingnut is tightened.  The outer tube is held securely inside the clutch block by the set screw.  However, even without the set screw, the tube will not move around during operation.

Sean
Sorry I answered this a year late.

Yes, your multimeter will tell you which pickups are dead. 

See https://ep-forum.com/smf/index.php?topic=9989.msg55589#msg55589

and https://ep-forum.com/smf/index.php?topic=10307.msg57408#msg57408

Wire your 49-key harp in groups-of-three, like the diagram attached.

We would love to see photos of your creation!  Can you get it down below 80 pounds?

The wire used to wrap the pickups is very thin "enameled" wire... something like 36AWG or 38AWG.
I don't believe you can get wire with old-fashioned enamel, now they use polyurethane (and it is 100% just great).  I assume that's what you have.  That small-gauge wire is only 0.004 inches or 0.005 inches in diameter...  that would be right about 0.1mm in diameter (not in cross-sectional area).  You need really thin insulation to give you enough space to wind enough turns to get the pickup up to 180Ω.

Here are dimensions of the regular 3" pickup.  Sorry about the cardboard box background.

One drawing in kilometers, one drawing in units related to the length of the king's big toe. 

Note that the electircal terminals have been cut off of this pickup.

Sean

There is no reason to use the 5-pin XLR unless you want the +and- 15V DC power for a preamp.

I recommend that you use the "power amp input" jacks to connect from your sound source to the FR-7710 amp.  I think this schematic matches your FR-7710 amp: https://www.fenderrhodes.com/org/ch11/fig11-3.jpg.  Zoom in to the upper left corner to see the input jack arrangements.

You will probably not be super happy with the Rhodes Stage Piano plugged in to these inputs, but if you put any kind of clean boost between the Rhodes Stage and the FR-7710 you can achieve happiness.  You could buy a Rhodes preamp, or you would be perfectly fine with a little mackie mixer (or even a cheaper alternative).  I like the mixer option, because it allows you to get EQ and as much gain as you will ever need, and it can provide left and right outputs from your mono source.

Let's hope you can get that amp running! 

Sean

I think that the trick is just don't give up.  Yes, it is a pain in the butt, but it will be worth it once you have every single bit of the felt and glue off the hammers, and have nice smooth cams.

Just watch Fred do it:
https://www.youtube.com/watch?v=HeHgO7ZFqfc

Oh, I wonder if you are only using 70% alcohol.  Go to the drugstore or hardware store and get yourself some 91% isopropyl alcohol. 

Sean

Oh, well.  A grinder is not a great cutting tool for aluminum.

An abrasive wheel will just smear the aluminum, rather than cut.  There are special cut-off wheels for aluminum that do a less-sucky job, but they still leave a nasty edge.

The circular saw blade leaves a remarkably clean edge.  But truthfully, either way we would hit the edge with a file and de-burring tools to clean it up after the cut.

So, you got it to work, and the Rhodes is alive again!  That's great.

Sean

Please promise me that you have called Vintage Vibe, and talked to Chris or Fred and asked them for the exact 73-key damper rail that you need.  If they really truly don't have it...

You will find that a radial-arm saw will cut the aluminum extrusion very cleanly.
You don't need a special blade sold explicity for aluminum, just use a carbide-tipped blade with as many teeth as you can afford or find handy.

Lubrication will help a LOT!  I use a wax bar that is sold for this purpose:  Olson Saw Blade Lubricant - $12 for a lifetime supply/little stick.  It makes a mess of your blade guard, and will probably get on the wall behind your saw, but it stops the aluminum from gumming up your saw blade.  You might still get a few teeth with aluminum stuck to them, but you can knock off the crud with a piece of wood (don't use your hand, it will be hot).  Inspect the blade before and after every cut!

Wear gloves, long sleeves, a face shield, and an apron.  Cutting through the aluminum creates a beautiful snowfall of hot aluminum flakes.

Clamp the workpiece tightly to the table of your saw.  The blade will pull it away from the fence, and you will get a crooked cut.  (Try a test cut before the final length cut.)  Really clamp it tight with at least two clamps, you really can't hold the large stock with your hand.  Don't try.

Don't cut slowly.  Cut just as fast as you would for wood.  If you go very slow with the aluminum, it will get very hot, and gum up the blade -- and then you will not get a clean cut.  Pull smoothly through the cut, don't stop, don't hesitate.  Not fast and herky-jerky, just be smoooth.

If you don't believe me, try cutting a thick-walled extrusion of aluminum that is not precious like the damper rail.  I have even cut one-inch round bar with the circular saw blade.

Sean

If the headphones were working, then the "earphone jack" was not working as a normally-closed switch.  The switch contacts on these jacks get dirty and corroded, and so you don't get signal through to the speaker load.  Replace that jack.

Now you have to fix the damage that you have done....

I think that getting the newly-manufactured amp is a great choice.  The best choice.

Sean

You should probably get the VV kit. 

The only thing to beware with the VV kits is that they supply transistors that have the wrong pinout order, so you have to make sure that you re-orient the transistor to get the leads installed in the right place.  Look in the "instructions" tab to see their only guidance related to this.

Look at the "what's included" tab.  Their standard kit includes all the caps, and also the 5W power resistors.  Very nice.

If you are new to working with a soldering iron, find a friend who has more experience. 

Personally, I would want to clean up that ugly mounting job done on the power transistors, and the VV "complete" kit would take care of that.  You should only do this if you are confident that you can do a much cleaner job than the upside-down mounting shown in your photo.  The schematic indicates that you might have to change some resistor values to get the bias right (R23 and R25).

After you are done soldering, clean off the flux with alcohol and q-tips.  The local drug store should have 91% Isopropyl Alcohol (70% works okay).

Don't forget to inspect your work as you go.  Make sure that every single capacitor is oriented with the right polarity.

Sean

Don't kid yourself that these 50-year-old capacitors are still great. Just because a DMM measured their capacitance does not mean that they are not leaky at higher voltage.  They could have elevated ESR, they could change in value very significantly with temperature.  They are not young anymore, so they may fail or falter soon after you start using the Wurly regularly.  If this were my old Wurly preamp and amplifier, I would replace each and every electrolytic capacitor in one afternoon and never worry about it ever again.

That blue #6 capacitor is directly connected to the speaker output.  I would want a capacitor with the lowest possible ESR, and a good rating for ripple current.  The schematic says 500μF 50V.  I would search Mouser and Digikey for one rated for 100V (because it won't cost much more), and get an axial-lead can that is similar in length to the original for mounting on that old circuit board.  (The mounting clip makes little difference, but it is cute.)

The big silver (1000μF 50V) cap #9 spends all-day every-day at 42V DC (plus ripple).  I would order a 1000uf cap rated at 100V, and get the lowest ESR rating and highest ripple-current rating I could find. 

For less than ten bucks each, you can get a low-ESR (less than 200milliOhms, some below 100mΩ) axial-lead aluminum-can capacitor with good temperature rating (85°C is fine)(longest hours is best).


ALL of the small electrolytic capacitors should be replaced with modern radial-lead caps that can be mounted standing up without their lead wires exposed.  Yes, you may have to bend and spread the lead wires to fit.  Get capacitors that have the same farad-rating, with a voltage-rating that is equal or above the original capacitor's voltage-rating.

Before you remove all the caps from the board, take a photo of the board, then print the photo and mark it for + and - polarity on all of the caps.  Then you can double-check yourself when installing the new caps.

Sean

Thirteen bucks?  I am tempted to get it just to play with.

What are you using for input power? 
A nine volt battery won't last long, nor provide much current.  (But this I want to try.)


If your Janus preamp "doesn't really do much amplifying" then something is obviously wrong.


https://a.co/d/2zPOzfS  "DrOK" Micro Boost Voltage Converter...

Sean

Brewski,

If I had this preamp in my house, I would test it with battery power.  It is a lot easier than any other way.

The hardest part is slapping together a wiring harness that plugs in to the preamp.  Since I don't have any four-pin plugs on hand, I would solder little test leads to the back side of the connector, or I would try to cut down some spade lugs to shove into each terminal of the connector.  You can also use alligator clips, but I would recommend the little J-hook style test leads. 

Be careful if you connect to the back of the 4-pin connector - it is very easy for the little clips to slip off and bang into another pin.  It is very easy to accidentally dump the full DC power into pin2 or pin3 and damage your test power amp.  For that reason alone, I use a cheap 9V-battery-powered toy amp as my testing amp.  Also, connect your clip to the preamp first, then connect the other end to the battery.

I like to use the least-fiddly setup as possible.  Get a box of little connectors from Amazon: WAGO 221 LEVER-NUTS.  Scroll down until you see the pack of 25 for thirteen bucks.  You can plug various size wires into these connectors, lift the lever to change connections, and tape the connector to your bench to keep things from moving around.  For benchtop testing, these connectors are re-useable.  (Mark them as used, so you never install a used connector in an AC box in your house.)


You just need to get the positive terminal of your battery to preamp pin 1, and the negative terminal of your battery to pin 4 (which is also the audio ground for the two channels).  Connect a 1/4" jack between pin 4 ground and pin 2 audio out, and another jack between pin 4 ground and pin 3 audio out.

You can use three nine volt batteries in series to get a little more than 25V, or you might have a power tool that uses a 24Volt battery.  If you are using three nine volt batteries in series, don't expect them to last for long lighting up those tremolo bulbs.  If the bulbs don't get to full brightness, you can put another group-of-three batteries in parallel with the first group for more current at the same source voltage.  Put a switch or quick-disconnect in the circuit to cut the power easily.

Also, if the audio sounds tinny (no low end), add a "bypass" capacitor across the power supply (battery) terminals.  Honestly, you don't need a huge electrolytic cap, something smaller than 50uF will probably be fine for testing with 9V batteries.  You should be able to notice the improved bass response by using a little 10uF MLCC ceramic cap for bypass (if you have a handful of them, put them in parallel).  The bypass capacitors are easier to manage on a little breadboard, but it isn't too hard to manage if you use the 5-hole Wago connectors for the +24V and Ground bus connections.

A few years ago, I did some calculations to predict that the Peterson preamp will probably draw less than 300mA:
https://ep-forum.com/smf/index.php?topic=9995.msg55633#msg55633

Study this schematic:
https://www.fenderrhodes.com/org/ch11/fig11-8.jpg

BTW, I have lots of experience with Rhodes power supplies for the Janus preamps.  See https://ep-forum.com/smf/index.php?topic=9657.0


Oh, I guess I didn't mention this:  take the preamp out of the piano before testing.  Remove the whole name rail, and remove the knobs, and unscrew the preamp from the rail.  If you need to run a long cable from the harp connector to the test rig, you can plug the long cable from the harp into the Accessory 2 (lower) jack of the preamp (and leave the existing RCA cable that hangs out the back of the preamp sitting there idle).

Wait - one more thing: this testing rig will be a little bit noisy, because nothing is shielded nor truly grounded.  I find that tolerating the noise is easier than trying to eliminate it with aluminum foil and ground wires.

Whatever you do, take photos and post them!

Sean

Mr Lawrence,

Get the MXR Phase 95 (Dunlop model # M290).  You will like it a lot.

Watch this video demo of phase 95 with a Rhodes:
https://www.youtube.com/watch?v=0TVePtJihOs

The Phase 95 can do everything a Phase 90 can do (four phaser stages), and everything that a Phase 45 can do (two phaser stages) - both MXR block logo types (with emphasized feedback), and MXR script logo types (without extra feedback). 

The little thing is great, except for the blinding blue LED next to the stomp switch (the only mod I did was to change the LED to dim RED).  It is a fiddly little mod, but you can cut the legs of the blue LED right where the leads enter the 3mm plastic lens (don't cut them off at the circuit board).  This will leave two little stumps at the right height for you to graft another 3mm LED in there.  Wait.  Before you cut the LED out, make a little black mark with a sharpie pen on the PCB next to the negative leg (the side of the LED lens that has the flat edge at the bottom).  It is obviously very important to get the new LED installed with the right orientation.

There is a little plastic spacer below the LED that blocks your cutters from getting at the LED legs.  I just used my cutters (put on eye protection goggles) to shatter the plastic housing of the LED, and it broke off clean enough to remove the LED and the spacer, and then clean it up with the cutters. (Look closely to make sure you didn't get any bits and pieces stuck in the rest of the circuitry.)  Use the plastic spacer as a template to show you exactly how long you want to cut the leads on the new LED.

Then comes the hard part:  getting the new LED to sit there while you solder it to the old LED's legs.  I made two tiny lassos with sewing thread, and was able to knot each leg of the new LED in place, and then solder them together with good contact and the LED sitting straight up.  It may be a pain, but it is quicker and less risky than dis-assembling the pedal to get at the underside of the PCB and un-solder the LED.

I also don't really like the light that flashes at the speed rate.  I can see the setting on the knob right next to that annoying light.  This LED also gets annoying bright blue if you set the pedal for Phase 90 mode.  And if that nasty blue LED wasn't there, I wouldn't be blinded every time I look at the pedal, and I could read the knob. 

I think the pedal would be more fun if the little mode switches could be toe-bean operated, but that won't work with the tiny little pedal chassis.  I decided it wasn't worth the time and money to put it into a big new chassis with three stomp switches.

At least the power jack is in the right place - on the far back end.

I can't watch the video portion of the Phase 95 demo at:
https://www.jimdunlop.com/mxr-phase-95/#tabTargetproductDemo
(but the audio is good showing your ears what the phaser can do to a guitar.)

See also the little pdf manual.  It tells you exactly why you want the Phase 95 - so you can push the "script" button to remove R28 and all that feedback wetness, because there are times when you don't want it.

Also, sometimes I power mine with a 9V battery by just getting a "9V battery to 5.2mm x2.1mm male tip-negative barrel connector" like https://www.amazon.com/Mr-Power-Battery-Converter-Connector-cable/dp/B07FCZZ5JF




Sean

There is a good chance that the hammer flange is broken.

There is a smaller chance that the hammer is simply not seated in the hammer flange.

Sean,

You will find it remarkably easy to remove all the screws and slide all the pickups forward onto a large cardboard or wooden board.  You can run a strip of masking tape across the pickup mounting tangs if you want to keep them less jumbled. (You can even remove the whole pickup rail from the piano first if you want to.)

Some pianos may have the far left or far right connection soldered rather than a eyelet terminal.  In that case you should clip the wire, and install an eyelet terminal (or simply unscrew the RCA jack and let it move with the pickups.

Sean

Since 18 Guage braided wire is the only size available, I think that is what you should use.  I think it will look a little beefier than the original, but I can't find anything smaller.

Does anyone else know a source for the braided wire that is tinned, not flattened, and made with dainty individual strands.  All the braided wire I have seen recently is made of much thicker and fewer individual strands.

Where can we buy the right stuff in small quantities?

Sean

Christoph,

It might be so.  I dunno.  I never thought of that befo.  You could sit an extra pickup next door to the lowest E, but....

The distance from the tip of the tine to the tip of the pickup is a very strong factor.  Also, those low notes sound very different depending on how high the tine points above the pickup tip, so adjust the timbre setting to be identical.

I believe the tine length and tuning spring position can make a big difference.  If one tine is cut longer than ideal, and the tuning spring is pushed further up (away from the tine tip) - and the other tine is cut shorter than ideal, and the tuning spring is sitting very close to the tip of the tine... they will react differently to the hammer blow, and may sound different.

I assume that you have installed fresh new chewy grommets.  And we have to hope that the hammer tips are the same hardness.

And we are not done yet!  There is yet another variation from note-to-note... the StrikeLine!  It shouldn't make a huge difference between neighboring tines, but sometimes it is enough to be a bother.  Be aware that variations in the very large escapement at the very low notes can cause significant differences in the strike point where the hammer tip contacts the tine.

So you get to play around with all these adjustments before you get exactly the tone you want:
1.  Escapement Screw
2.  Timbre Screw
3.  Tuning spring position on the tine and tine length
4.  Pickup position
5.  Strikeline
6.  Hammer Tip hardness
7.  Grommet freshness

All that being said, I bet moving the pickup in a tiny bit will fix your woes.

Sean