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Messages - pnoboy

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1
The Fender Rhodes Electric Piano / Re: Sound Adjustment Advices?
« on: February 19, 2019, 11:36:56 AM »
3 to 4 mm  is too much space from tine to pickup.  1 to 2 mm  is better.  The best way to measure spacing is to put a probe of known thickness between the tine and pickup, while holding the probe accurately vertical.  A 1.5 mm flat stick stick of wood, aluminum, or plastic should work well.  Think of something shaped like a skinny tongue depressor.  The "bass boost" control in the stage piano is actually a bass-cut control.  The harp going into a hifi speaker like the Yamaha you mention will definitely produce a bassy, tubby sound.  An amp and speaker meant for musical-instrument use should sound quite a lot better.  Most of us use guitar amplifiers of one sort or another.  When I said 200 Hz give or take 50 Hz, I meant a notch somewhere between 150 and 250 Hz.  Adjust the voicing screw by ear, don't worry about the tine's exact vertical position, which is difficult to measure anyway.

If you don't use the front-panel controls on the piano, expect to need to turn the bass control on the amp down a bit.


2
The Fender Rhodes Electric Piano / Re: Preamp beat
« on: February 18, 2019, 04:23:45 PM »
Someone with a knowledge of electronics need to trace the signal through your preamp.  No doubt some component(s) in the tremolo circuit have problems.

3
The Fender Rhodes Electric Piano / Re: Sound Adjustment Advices?
« on: February 18, 2019, 04:21:58 PM »
A few things come to mind.  First what is the tine to pickup spacing, especially in the bass?  Second, I assume you've played with the voicing screws in the bass to bring out more overtones, have you?  What happens to the sound if you turn the bass control down?  Finally, many Rhodes sound tubby unless one puts a dip in the frequency response around 200 Hz, give or take about 50 Hz, depending on the amp and speakers/cabinet.  This issue is most easily tested by using a parametric equalizer.  What are you using for speakers and speaker cabinet?    BTW, what happens to the bass sound if you play ff?  At some point, you should hear overtones.  Rhodes pianos will almost always sound tubby without the right combination of frequency-response settings and an appropriate speaker cabinet.

4
The Fender Rhodes Electric Piano / Re: Rhodes Tine Length Curve
« on: February 10, 2019, 04:56:08 PM »
I think that one thing that will throw off the smooth curve you are looking for are the tuning springs.  At different points within the compass of the piano, Fender uses different weight springs.  These different weights change abruptly, i.e., the springs immediately transition from one weight to another--they don't change in some smooth manner.

5
The Fender Rhodes Electric Piano / Re: Rhodes Stage MKI Hiss
« on: January 30, 2019, 03:34:01 PM »
I've found stage pianos to be pretty dead quiet.  If you are hearing hiss, look to your signal chain, some interference, or even a ground loop, though ground loops usually produce hum.

6
Parts, Service, Maintenance & Repairs / Re: MKV Hammer Tips
« on: January 30, 2019, 11:41:00 AM »
I tried a VV set of graduated tips on my '78 stage piano and, FWIW, found the rubber too hard--especially at the bass end.  I could easily feel the difference in the rubber Fender used at the bass end and the rubber supplied by VV.  The Fender rubber was noticeably softer.  The hardness of the bass VV tips caused the bass notes to produce too much noise.

7
The Fender Rhodes Electric Piano / Re: Rhodes Stage MKI Hiss
« on: January 30, 2019, 11:37:20 AM »
If the harp of your stage piano is connected to the standard front-panel controls, it is already seeing a 10k impedance, and if you then connect it to anything with an input impedance higher than about 100k,  the load on the harp has not changed by any appreciable amount.  If you want to hear more of the "ting " of the hammers hitting the tines, then you must bypass the front-panel controls, or scale the values up to a higher impedance.

8
The Fender Rhodes Electric Piano / Re: Tine issues
« on: January 29, 2019, 12:05:27 PM »
Those hex thin-head  screws Fender used to screw the tines to the tone bars are far from ideal.  Socket-head cap screws are SO much nicer to use.  If I were redoing a whole piano, I'd dump the original screws and get cap screws instead.

9
Parts, Service, Maintenance & Repairs / Re: DIY Sustain Pedal
« on: December 29, 2018, 04:43:08 PM »
IMO, pick the lightest one if you gig, make sure there is minimal slop in the pivot, apply felt or rubber appropriately so the pedal doesn't clang at either end of its travel, and select some suitably "sticky" feet so the pedal doesn't slide around in use.  The use of wood is interesting--it has the potential for being light and stiff enough to do the job; I like the idea.  BTW, the use of a spring pin, as Fender did, for the pivot, is a poor choice. 

10
PVC-E glue is still available from Schaff and Pianotek--probably other sources as well, but I didn't check.

11
It's hard to say, but the odd attack that you demonstrate could be caused by the tine swinging enough to wack into its damper.  Try this, while watching the dampers, depress the sustain pedal.  You should be able to move the dampers further down than they might be being moved by holding a key down.  If that's the case, hit that note again, and see if the sound is more normal. 

As far as the tone, it sounds very tinny, like there's something wrong with your amp, or something odd with your piano.  Do you have a guitar you could plug into your amp to see if that sounds normal?  If it does, try plugging the harp directly into your amp, bypassing the front-panel controls.  BTW, I assume you have a stage piano--is that the case?

12
Perfect. Thanks.

Is it particularly flexible? If I'm not mistaken, those glue sticks are kinda rubbery. Is that the consistency after it's cured?

One has to be careful when specifying adhesive.  For example, epoxy can be extremely strong, but bonds poorly to many plastics, and needs a somewhat rough surface for best strength.  Many epoxies are rigid when cured and will readily peel off flexible materials.  There are many types of hot-glue sticks available, but most consumer stores will sell very few.  Just FYI, 3M makes a large array of hot-melt adhesives.  Check out https://www.3m.com/3M/en_US/company-us/all-3m-products/~/All-3M-Products/Adhesives-Tapes/Industrial-Adhesives-and-Tapes/Non-Structural-Adhesives/Hot-Melt-Adhesives/?N=5002385+8710676+8710815+8710968+8711017+8716336+3294857497&rt=r3

13
The Fender Rhodes Electric Piano / Re: Tone Bar Cleaning
« on: November 25, 2018, 10:50:06 AM »
Your tonebars can be sent to a plater for yellow chromate.  Also, check out this youbute video. https://www.youtube.com/watch?v=UF-lhfpwlMs

14
Mellow tone comes from the type of hammer tips used, EQ, and setup. The tone (voicing) can be altered with set up, so it is adjustable to a point by the user without spending any money. Does the MKII have wooden or all plastic keys? I personally would stay away from the all plastic keys.

I agree with Steveo's analysis.  Hammer tips have a huge and under-appreciated effect on tone, as do the amp, the speaker(s), and the speaker cabinet.

15
Parts, Service, Maintenance & Repairs / Re: Bent tines?
« on: October 27, 2018, 06:34:06 AM »
I agree--bent tines are very unlikely.  However, near the center of your picture you can see 2 tines that are not well aligned with their pickups.  However, you can also see a gap between the pickups.  If you loosen the pickups and move them so as to close the gap, I think the poor alignment will mostly disappear.

16
The Fender Rhodes Electric Piano / Re: Is this mould on my keys?
« on: October 24, 2018, 06:41:00 AM »
Chlorine bleach is the standard method for mold and mildew removal.  Scrubbing it on with a toothbrush for about a minute, then wiping the key down with a micro-fiber cloth should work.  The darkened areas could be water stains, I suppose.  If so, and bleach doesn't work, oxalic acid is the go-to product.  I think you are being wise in not letting water sit on the keys for very long.

17
The Fender Rhodes Electric Piano / Re: Possibly Modded Rhodes?
« on: October 14, 2018, 10:53:16 AM »
Yes, pictures--from the back of the name rail, to show the wiring of the jacks, and also at the rear left of the piano, where the cable from the name rail plugs into the harp.  Without them no one can help you.

18
ABS plastic does not have complete resistance to alcohols.  Acetone will severely attack it.  I wouldn't soak my hammers in alcohol.  Soaking the felt in alcohol for just as long as it takes to come loose from the hammer is probably OK.  Proceed with caution.

19
The Fender Rhodes Electric Piano / Re: Is this mould on my keys?
« on: October 08, 2018, 05:56:39 PM »
I've had good results cleaning Tolex by using a plastic-bristled scrub brush and a spray cleaner like Method.  Spray, scrub, wipe, rinse, dry.  It worked like a charm for me.

20
I agree.  If the tine-to-pickup spacing is set accurately and consistently, and the speaker system is one that works well with a Rhodes, then a slight bass rolloff and a small notch filter of maybe 2 dB set somewhere between 100 and 200 Hz depending on the amp and speakers, should do the trick.  I have owned 3 Rhodes pianos over the years, and all were dead quiet.  Whenever I encountered noise problems it was always a deficiency in the amp and not the Rhodes itself.  Some guitar amps are poorly designed, or much more commonly, reasonably well designed, but with cheap components.  The biggest problem is often the carbon-composition resistors, which are the noisiest resistors around, and yet very common in many guitar amps.

21
Parts, Service, Maintenance & Repairs / Re: Loose hammers
« on: September 03, 2018, 12:07:51 PM »
Look at the plastic pins that are part of the hammer, and look at the holes in the hammer combs into which the hammer pins snap.  It's go to be one or the other, or perhaps both.

22
Tim,

Yes, you have described exactly what to do, and also the difficulty of running the test.  I did a somewhat similar test myself, though I I can't claim it proved too much, because my ears were the only judge, and it was not even single-blind, let alone double blind.  In any case, noticing that the stage piano output is loaded by the 10 k volume pot, and noticing that the sound of the stage piano is quite different when taken directly from the harp, I made the following test.

I set up a little fixture by which I could quickly add resistors in parallel to the harp's output, and then connected the harp output directly to an amp with a 1 meg input impedance.  Here's what I found:

10k vs. 1 meg--pretty dramatic difference in tone.  the 10k resistor in combination with the inductance of the harp formed a low-pass filter that filtered out much of the hammer-impact sound, which made the piano sound duller.

20k vs 1 meg--also, an easily detectable difference in tone, but surprisingly less dramatic than 10k vs. 1 meg.

50k vs. 1 meg--I could still hear a difference, but it was small, and I wasn't at all sure that it was significant.

100k vs. 1 meg--any difference was very small, indeed.  I couldn't be sure that I could play anything on the piano repeatably enough to accurately discern any difference.

So, there you have it--I found a 100k input impedance sufficient to reveal the full sound of the harp.  Maybe a different pair of ears would have been more discerning, but at some point, small adjustments of the amp's tone controls would be far more significant than worrying about the ultimate in high-impedance preamps.  Also, I didn't notice any changes in noise, though the 10k resistor did cut down the output from the harp, which had to have a slight negative effect on SNR.

23
I never knew that technical discussions and debates were pi--ing contests.  The history of science would be nowhere without them, as responses to scientific papers and hypotheses, both critical and elucidative, are an essential part of the scientific method. 

24
Let's grant that you can hear a difference, though a double-blind test would be necessary to remove all doubt.  The real question, however, is why.  There are many possibilities, and you claim that the difference is input impedance.  I checked, and the Radial device has an input impedance of 220 k--we were discussing the difference between 1 meg and 10 meg input impedance.  At 220 k, a very slight difference in tone might be possible to discern, but a blind test would be in order.  At input impedances of 1 meg or higher I claim no difference would be detectable.  However, I am a man of science, and if a valid double-blind test proved me wrong, I would be happy to admit it.  Let me say two things in closing-- one, that good double-blind tests are more difficult to set up and run than most people appreciate, and two, there are many, many things in the signal chain that have a significantly more profound effect on the sound of the Rhodes than the input impedance of almost any normal amp one would use.

Also, allow me to ask a question of you--when you were comparing the countryman to the Radial, were you taking the signal directly from the harp or from the piano's front panel?

25
This amp uses only one leg of what's presumably a 12.6V winding to create the 6.3V for the heaters. The other leg is grounded, so there's nothing to twist the heater wires with. I have shielded them with foil tape and pressed them into corners as best as I can.

Your mod to your 140 volume pot is interesting. I just tried shorting Hot-Wiper and got nothing but 60Hz hum. Perhaps I should swap the pot before I do anything else more serious.

Thanks for the Uncle Doug video. I remember it from years ago and I actually watched it earlier today too. As far as I can tell, it confirms that I do not have tube noise.

I'm confident it's a ground loop, and I'm hoping if I can protect the preamp section from loops that perhaps I won't have to mess with the rest!

There are so many potential causes for hum, no one could possibly predict with confidence what would ameliorate your issue unless they had solved the identical problem with the same model piano.  One thing you mentioned that is almost ALWAYS a source of hum is heaters powered by a grounded AC power source.  The usual way to power tube heaters is through an isolated transformer winding that is configured to have equal and opposite voltages at the connections to the tubes.  There are typically 2 ways of achieving this result.  One is to use a center-tapped winding, whose center tap is grounded.  The other is to connect the isolated heater voltages to ground through equal resistors, or to use a pot whose center tap is grounded.  I have a tube amp I sometimes use with my Rhodes piano that has a so-called hum balance control, which is, in fact, a pot connected across the heater windings.  When set just right, amp hum almost completely disappears.  Setting the pot to one end of the other results in plenty of hum.  One reader mentioned Uncle Doug's dissertation on hum.  One point is germane to your problem.  Hum from a full-wave rectified power supply is at 120 Hz.  Hum from an unbalanced heater connection is at 60 Hz.  Good luck!

26
I am 99.99% sure that 10Meg input impedance is not the reason for the quietness of the Countryman DI.

My empirical experiments are pretty strong evidence that is hard to dispute.  I don't know what is inside the Countryman other than ad copy claiming it has FET input stages, and the electronics are encased in epoxy. 

In fact I learned of the trick on Gearslutz from Mr. Jim Williams, an audio engineer with a long history of improving audio equipment for a few decades including some major name recording artists from the 1970s.

Quote
All versions of the stage piano have input impedances at least 10X lower than 1Meg.

No, you're confusing input impedance with output impedance.  Stage piano outputs have an output impedance.

Quote
I have several amp heads, 1 tube and 3 SS, all with 1Meg input impedance, and all are dead quiet.

As do I.  But guitar amps cut off at about 5K because guitars don't do any higher, so that 5K upper limit is filtering off the noise.

The big difference is the OP wants to record his Rhodes without a guitar amp and direct into a recorder, which is full bandwidth out to 20K where the noise will now be clearly heard.

In my experiments with various DIs and amps, the pickups on the Rhodes are very sensitive to loading from input impedances.  Another member here on EP forum graphed the frequency response of the pickups with varying input impedances and it is very revealing, pretty much mirrors my results.  Their tone changes, and the noise varies.  The pickups seem to be happy with an optimal input impedance.

Actually, I'm not confusing input and output impedances.  The impedances of the suitcase pianos I referred to are the input impedances of the preamp circuitry they used, not the output impedance of the harp.  Sorry if my writing wasn't clear.  As for amp frequency response, all my amps are flat out to beyond 10 kHz, and not more than 2 or 3 dB down at 20 kHz.  A Rhodes piano doesn't put out much signal beyond 5 kHz or so, anyway.

In a double-blind test, properly set up, I claim that no one would be able to distinguish any tonal or noise difference between a preamp having an input impedance of 1 meg ohm and 10 meg ohm.  Also consider that the capacitance of the cable that connects the harp to the preamp of choice filters out some highs.  If we assume a cable capacitance of 200 pF, which would account for the cable from the harp to the front panel, and the front panel to the preamp, the impedance of that capacitance at 10 kHz is about 79 k.  That impedance, along with with the fairly low output impedance of the harp, makes it's just a bit hard for me to accept the idea that anyone could hear a difference between 1 and 10 meg ohm preamp input impedance.  I simply don't believe it.  There could be any number of reasons why the Countryman sounds better.

27
I am 99.99% sure that 10Meg input impedance is not the reason for the quietness of the Countryman DI.  All versions of the stage piano have input impedances at least 10X lower than 1Meg.  I have several amp heads, 1 tube and 3 SS, all with 1Meg input impedance, and all are dead quiet

28
Maybe your piano is too quiet.  Are the pickups an appropriate distance from the tines?  Could you possibly have a bad  electrical connection? A Rhodes piano should work well with any ordinary guitar amp in terms of its signal.  To put it another way, a guitar amp should have plenty of gain for a Rhodes.

29
The first thing to do is to figure out if the noise is coming from the Rhodes' output, from some kind of ground loop or EMI, or from the circuitry into which you're feeding the Rhodes' signal.  For example, if you take the signal from the  1/4" jack on the Rhodes' front panel, turn the volume control all the way down.  This connects the output of the Rhodes' to its common (ground).  Did the noise go away?  If not, the noise is not pickup noise from the Rhodes.  Next, unplug the cord that connects the Rhodes to your circuitry.  Did the noise go away?  If so, there's probably some kind of EMI in the area.  If not, maybe the noise is your circuitry.

30
Noise is usually other gear or bad ground connections on the Rhodes.  Rhodes pianos are dead quiet when set up properly.

Yes, that's been my experience, also.

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