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Messages - pnoboy

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31
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

32
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

33
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.

34
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.

35
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.

36
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.

37
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.

38
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.

39
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.

40
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.

41
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.

42
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. 

43
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?

44
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!

45
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.

46
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

47
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.

48
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.

49
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.

50
The Fender Rhodes Electric Piano / nice write-up
« on: July 25, 2018, 06:18:13 PM »
I ran across this piece in my travels--
http://daily.redbullmusicacademy.com/2017/11/instrumental-instruments-fender-rhodes

It's got some of its facts wrong, but, all in all, a pleasant history of the instrument.

51
The "overshoot" is only caused by the fact that the harp is not in place.  It is perfectly normal for the hammers to move in the way you show.  If the harp were in place, the tines would limit the upper travel limit of the hammers.  That's the whole point of the action--it propels the hammers into the tines, at which point the hammers should then bounce off the tines, hopefully to stay in check until the key is released.

52
The bridle straps need to be adjusted so that when the key is at rest, and the dampers are touching the tines, the straps are loose, and would allow about 1/8" (3 mm) further upward movement of the hammer tips before being tight.  That will allow good damping, and also cause the dampers to be pulled sufficiently away from the tines so as not to contact the tines on a hard blow, when the key is down.  These adjustments are more critical at the bass end, where the tines swing in such a wide arc.

The bridle straps do not prevent the hammer from swinging, nor is it their purpose

53
There is nothing inherent in the design of the Rhodes or the Wurli that produces distorted, compressed, or saturated bass notes.  Muddiness, to some people could mean lacking in harmonics.  It's a term that is used imprecisely, and therefore is hard to interpret.    The Wurli typically produces bass and low-mid notes with more harmonics than the Rhodes and therefore may be more to your liking. 

54
The Fender Rhodes Electric Piano / Re: Miracle Mod Install Problem?
« on: July 15, 2018, 01:42:42 PM »
The much greater escapement in the bass definitely affects the hammer's ability to lock in, as you call it.  IMO, the Rhodes' simplified action works quite well toward the treble end of the piano and much less successfully toward the bass end.

55
It's got plenty of power, but being a switched regulator, it may add some audible noise.  It's so cheap, why not give it a try.

56
The Fender Rhodes Electric Piano / Re: 1978 Suitcase Amp Distortion
« on: July 02, 2018, 11:28:11 AM »
A while ago, someone posted information on a modern replacement for the Peterson power amps.  The Peterson power amps might have been considered to be OK when designed, but even by 40-yr old standards, they're pretty bad. 

57
The Fender Rhodes Electric Piano / Re: My first rhodes "repaired"
« on: June 29, 2018, 06:22:54 PM »
I don't believe felt hammer tips will give more bark; if anything I would expect them to reduce it.

58
Good advice--epoxy is indeed best for this type of repair.

59
If the dampers aren't working correctly, then you need to figure out what the problem is and fix it.  The miracle mod is unlikely to do that except by chance.  If you haven't checked, be sure there is a bit of looseness in the bridal straps when the dampers are resting on the tines.  Did you check that the damper tray is completely away from the dampers when the sustain pedal is released.  You mentioned checking the damper felt, and I it seems you checked that the dampers weren't bent such that the dampers had little force against the tines.  The problem has to be something simple--there's not much to the damper mechanism in a Rhodes piano.

60
Preamps, Modifications & Upgrades / Re: Led tap off on Warneck amp
« on: May 20, 2018, 03:57:51 PM »
Use this calculator to work out what resistor you need:

http://led.linear1.org/1led.wiz

Tim suggests taking it off the 28v pad, a typical LED I've found online (10mm Orange LED) has a forward voltage of 2.2v and a forward current of 20ma.

The calculator suggests a 1.5k ohm 2W resistor (2W as it needs to dissipate the heat generated.)

Just so it's clear for others. You should have a red wire connecting to the 28v pad, then to the resistor, this then connects to the LED on the positive side, then the other side can have a wire going straight from the LED to ground (I use a black wire to help identification.)

Like so:



Good information, but if one uses a high-efficiency LED, 10 mA may be more suitable.

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