diagnosing dull notes

[Abraham]

Hey guys, I have some trouble with keys #27 & #30 producing less output compared to the rest of them. I know there are two options, being: a) bad tine; b) bad pickup. What I don't know is how to make sure wich one is causing the problem before ordering a replacement (because shipping cost is WAY expensive).

Of course I tried moving the pickup as close as possible, resulting in more bark but not higher output. Also I have noticed whenever I press those particular keys harder, they dont sound louder but right the opposite (choking?)

I know pickups are working but I don't know how to test if they're OK. I have a multimeter but I don't know what do I have to check (ohms?) and what are acceptable values.

Besides, notes seem to output OK while picked with my fingers, so I think this might have something to do with the tine "hot spot" (bad tine?)

Key, pedestal and hammer don't have any noticeable difference from their neighbours.

Any help is appreciated!

[Abraham]

Nevermind I reminded this vv video: http://www.youtube.com/watch?v=5lkmDed4H-4

Very useful, lots of information on the troubleshoting procedure.

Any further comments are appreciated tough.

[cfishel15]

This begs a question that I've always wondered about: what exactly causes a bad tine? Do hairline cracks form in the metal which cause it to lose tonality?

[Chris Carroll]

Tines can go bad by metal fatigue over and over use of a tines will alter the structural integrity of the tine. If you take a tine and bend it by hand and then bend it back to it's original state- That tine will never sound the same again because it has been fatigued and now the composition has changed. Also, the Generator block can loosen over time from vibrations causing loss of vibration in the tine. If a tine is not seated perfectly within the block this will aslo affect how the tine plays and vibrates- There are inherently many tines that are born bad from the moment they are joined incorrectly for a number of reasons. The Rhodes Factory is famous for allowing many to pass into their pianos without proper QC. This is also the reason you see many Rhodes pianos with double springs in the bass - You can also get this type of oscillation from shorter tines but double springing is not an option in this case. This double springing keeps the wild figure 8 oscillation from occuring, at least it tempers them back to a usable sound. The fact is that these tines were inserted into the blocks with one or more variations not correct resulting in a tine pressed off center.

Dull tines can also be the victem of improper strike line due to hammers that are not aligned or hammer tips too soft. Could also be the escapement, improper lost motion of the damper will cause immproper lifting of the damper. Try that tine in another spot to see how it reacts. Does it have the proper spring on it? Is the end Square-

You say the pick up is good, but it could have lost magnatism, which will put out a low volume shallow tone. You can take a couple of very strong PM magnets and try to re charge the pick up. Make sure your polarity is correct first.

Good Luck- if you need a tine  www.vintagevibe.com

[The Real MC]

CBS is infamous for allowing many to pass into Rhodes pianos without proper QC.

fixed

[goat1927]

Hi all,

If possible, would someone be able to describe how to "...take a couple of very strong PM magnets and try to re charge the pick up. Make sure your polarity is correct first," as noted below by Quadrapuss? I'm diagnosing a similar issue and want to know how this can be done.

Thanks!

MJ

[BerneseMtnDog]

If you want to eliminate the pickup as the potential problem you can remove the tine and tone bar from the next note over (assuming that note sounds good) and instal it in the suspect position.  Adjust the pickup for proper volume and the tine for timbre and see if the sound is good or not.  In my experience with restoring my 75' Stage, the tine is far more likely to be fatigued and worn out than the pickup bad.

Steve

[Tine-E]

I've encountered two dull notes in the highest octave.

Testing the pickups by tapping produces equally strong outputs as neighboring pickups.

I removed the tonebar (with the tines) and finger plucked the tine ends and found them ringing with good sustain!

I simply could not find the culprit when the tonebars are back in place, the notes just are dull and have weak outputs.

[BerneseMtnDog]

I've had to use those clip things that add mass on several notes of the highest octave to get proper sustain.  Maybe that's the issue???

Steve

[Tine-E]

I don't recall if I've added those for increased mass but let me try it.  Thanks for the reminder Steve.

Luis

[Ben Bove]

Just to make sure we're on the same page - are you saying they're low in volume or sustain?  If it is low volume and you've tried sliding your pickups closer, see about lowering the tonebar closer to the center of the pickup.  There's a minimal tone change in the upper register as you get closer to center, so by lowering the tonebar you can get it closer within the pickup field (provided the tine doesn't hit the pickup magnet, or the damper get hung up on the magnet either)

[Tine-E]

I've pushed the pickup as close as possible to the tine avoiding vibration collision and the output is very weak. When removed from the harp and plucked, the tine rings and sustains well!

When placed on another position, same 'muffling' happens!

[voltergeist]

I've pushed the pickup as close as possible to the tine avoiding vibration collision and the output is very weak. When removed from the harp and plucked, the tine rings and sustains well!

When placed on another position, same 'muffling' happens!

Is your escapement correct?  Is the screw tight?  (If you tightened with a wrench the answer is 'no'.)

There have been a few instances where I was driven crazy by some high notes; tried everything, nothing worked.  Replaced the tine with a new one and it rang perfectly.  When all else fails, try replacing the tine. 

Given that it behaves the same way in two different positions, that would seem to rule out a bad pickup and a bad hammer tip.  If it were me, I'd order a couple brand new short tines from VV.  That will either fix the problem and you're done, or rule out the tines as the problem.

[Max Brink]

All of the above are good suggestions. Sometimes it can be an odd resonant frequency issue within the piano that is sucking out the tine's energy as it sustains. Here are a few techniques to use if this is the case:

1) In the uppermost octaves sometimes you can get better sustain by moving out the tine spring, and moving in the tonebar clip (and sometimes vice versa).

2) If you put pressure down on the tone bar screws and the note comes back to life when struck then add a washer or two between the screw head and the grommet. I usually start with putting a washer or two on the screw closest to the player.

3) Sometimes when this is the case replacing the tine with a slightly different length will solve the issue.


If these don't work out then I would consider replacing the tine. I suggest using vintage tines whenever possible matching them as close to the year as possible to get the timbre just right the way that it is supposed to sound for your model.

Also, do you have healthy grommets? I recommend dropping in a set of Retro Linear grommets if you haven't already.

[David Aubke]

1) In the uppermost octaves sometimes you can get better sustain by moving out the tine spring, and moving in the tonebar clip (and sometimes vice versa).

2) If you put pressure down on the tone bar screws and the note comes back to life when struck then add a washer or two between the screw head and the grommet. I usually start with putting a washer or two on the screw closest to the player.

1. Are you switching to a lighter tuning spring? How can you move it without changing the pitch?
2. Why would placing additional washers above the tone bar change anything except the depth at which the screw is driven? To change the tension on the spring without affecting the escapement, you'd have to put the washer at the bottom of the assembly.

[Max Brink]

1. Are you switching to a lighter tuning spring? How can you move it without changing the pitch?
2. Why would placing additional washers above the tone bar change anything except the depth at which the screw is driven? To change the tension on the spring without affecting the escapement, you'd have to put the washer at the bottom of the assembly.

1) Not switching to a lighter spring. The end pitch is the same because it's a two step process that balances itself out to a new equillibrium: a) move the tuning spring out lowering the pitch then b) move the tone bar clip in raising the pitch. Sometimes the inverse movements work and sometimes it takes a few attempts to find one that is right. In some cases the new equilibrium works out the resonant problems.

2) It's the weirdest fix that I have encountered and I use it all the time on dull notes in the upper register. If you notice a difference in the resonance of the note when you put a screw driver into the tone bar's screw then this is the solution. I imagine that it is changing the resonant frequency of the entire tone bar/tine assembly just enough to offset the loss in energy...

[David Aubke]

1. Are you switching to a lighter tuning spring? How can you move it without changing the pitch?
2. Why would placing additional washers above the tone bar change anything except the depth at which the screw is driven? To change the tension on the spring without affecting the escapement, you'd have to put the washer at the bottom of the assembly.

1) Not switching to a lighter spring. The end pitch is the same because it's a two step process that balances itself out to a new equillibrium: a) move the tuning spring out lowering the pitch then b) move the tone bar clip in raising the pitch. Sometimes the inverse movements work and sometimes it takes a few attempts to find one that is right. In some cases the new equilibrium works out the resonant problems.

2) It's the weirdest fix that I have encountered and I use it all the time on dull notes in the upper register. If you notice a difference in the resonance of the note when you put a screw driver into the tone bar's screw then this is the solution. I imagine that it is changing the resonant frequency of the entire tone bar/tine assembly just enough to offset the loss in energy...

That makes sense.

[voltergeist]

Max, I think that is the single best piece of information I've ever found on this forum.  Many, many thanks! 

Your timing is impeccable, since I'm currently refining the high register on my early '75 88 Satellite.  I tried your method last night, and sure enough, it worked like a charm.  Notes that had been vexing me for a long time were sustaining beautifully with excellent tone.  Even for notes that were already ringing 'well enough', some fine tuning with this method resulted in better sustain and purer tones.  Definately going to go back and apply this method to my '78 suitcase and the KMC.

One key point that I don't think Max explicitly stated is that these adjustments need to be made with a good tuner hooked up.  For every adjustment iteration, the assembly in question needs to be tuned to know if you're there.  You can actually fine tune (pitch wise) with the clip, which I hadn't realized previously.  So, I would move the tine spring a little sharp or flat, then bring it back in tune with the clip and see how it resonates.  The clip at the audience-side end of the tonebar is flat, and at the player side is sharp.  So, if you have the clip at the audience side end, you'd set the tine spring a little flat, then bring the pitch up by moving the clip back toward the player.  With the clip at the player end, set the tine spring a little sharp and bring it into tune pushing the clip toward the audience side.  The trick seems to be to get the combination such that the clip ends up in the ideal position when the assembly is at the desired pitch.

As far as I'm concerned, that's case closed on optimizing high register tone and sustain.  I figured there had to be a better way, and this is it.  All the myriad other things that can be wrong need to be right, but if they are, this method appears to be the secret to getting the rest of the way there.

[Tine-E]

Whoa! This issue is not as simple as it seems. But the varied approaches to isolating the cause makes the process(es) of restoration all worth it. ....plus the fun!

[voltergeist]

All of the above are good suggestions. Sometimes it can be an odd resonant frequency issue within the piano that is sucking out the tine's energy as it sustains. Here are a few techniques to use if this is the case:

1) In the uppermost octaves sometimes you can get better sustain by moving out the tine spring, and moving in the tonebar clip (and sometimes vice versa).

2) If you put pressure down on the tone bar screws and the note comes back to life when struck then add a washer or two between the screw head and the grommet. I usually start with putting a washer or two on the screw closest to the player.

3) Sometimes when this is the case replacing the tine with a slightly different length will solve the issue.

I hadn't thought of adding washers (seems obvious in retrospect, but...), so I've been experimenting with pianos I've got in the shop.

I've got a guy's '74 Stage in my shop now, and for some reason several notes in the high register (at least 2/3 of the register) on this piano are very sensitive to the washers.  Some responded to extra washers on the player side screw, some with extra washers on the audience-side screw, and some responded to thinner washers.  One note that I thought had a dead tine (it would just thud) is ringing beautifully with a stack of about 6 or 7 (!) extra washers on the audience side screw. 

I then went back to my KMC and did some experimenting with washers on it, and only one or two notes responded at all to changes in washers. 

I noticed that the notes that responded to extra washers were transferring a lot of vibration to the screwdriver.  Notes for which the screwdriver would not change the behavior did not seem to transfer any vibration to the screwdriver at all.  Also, some notes would get worse (less sustain) with the screwdriver on the screw, and those were the ones where I used thinner washers, which improved the tone and sustain. 

Thanks for the tip, Max!

[Tine-E]

I've done the washer fix on several lower register notes to increase the spring tension on the player side (since I did not have any of the heavy VV springs) which resulted to greatly reduced tine oscillations on those notes.

I've have to try this fix on the high register problem notes.

Great tip!