Shelter and Triplanar matching ?

Raul,

Thank you! - for coming in and trying to help. Like you, I've rarely heard of this problem with good equipment. This is a tough one. No need to apologize. This isn't "my" thread. Everyone should try to help if they can.

The main tonearm problem I can imagine causing this is damaged, dirty or misadjusted bearings. For two tonearms to have that problem (or any one problem) seems unlikely.

The fact that it's audible with the RB900 but more audible with the TP may simply be due to the TP's greater transparency. (Just guessing, I don't know the RB900.)

I am leaning toward this idea: inadequate resistance to stylus drag. Large dynamics and warps both temporarily increase and then decrease drag resistance on the platter. If the platter slows and then quickly comes back up to speed, pitch changes on piano decays would be audible. A stretch and rebound cycle in the elastic drive belt that most PV's use might be involved.

Andre,

If the problem continues with the new/repaired TP, try adjusting or replacing your drive belt. If that helps "some" but not enough, here's the $500 solution...

The PV's I've seen all used elastic belts. The stretch in the belt is meant to absorb motor vibrations and cogging (assuming the motor is AC), but of course the belt may also stretch for a moment due to increased stylus drag from big dynamics or warps. I have tried several elastic belts on my Teres tables. None of them could maintain good speed stability.

I know that a few PV owners were dis-satisfied with this aspect of their rigs. When they tried a Teres motor and belt the problem was solved. The Teres motor is a very quiet, non-cogging (DC) type. There is no need for an elastic belt to isolate it from the platter, so it uses 1/2" (~1cm) wide mylar tape. This results in much better platter/motor coupling, so better dynamics and speed stability. I believe Galibier and Redpoint motors are similar in this respect.

Good luck and keep us posted,
Doug

Hi DOUG HI RAUL

I completly agree about the idea that the TP increases the problem because of its performance rather than because of any damage on it (we will see this next week).

Doug : thanks for the Teres motors idea ( I have soon sended an E- mail to have details).

What do you both think about the idea that the stiffer the cartridge is the most perfect the records must be ?

Thanks

André

Andre,

I think your idea has merit, and it's consistent with my theory.

If stylus drag is slowing the platter and causing your tremolo, anything which alters the amount of drag could alter the amount of tremolo.

We've established that the tremolo is worse after a large dynamic note or a warp. What is similar about these two events? Answer: both of them are trying to deflect the stylus. This requires some force. If the motor/belt aren't stable enough to overcome the resistance of the stylus/cantilever/suspension, the platter may slow.

(Bad tonearm bearings could increase the arm's resistance to rising freely over a warp. This would increase VTF and drag, which is why I thought of it. But since both your arms have the problem to some degree this seems unlikely.)

The amount of stylus drag will vary with cartridge and with setup. Here are some of the factors I can think of:

VTF - higher VTF = more friction (pretty obvious)

Compliance - the stiffer the cartridge suspension the more it resists deflection, greater resistance to deflection = more friction

Stylus profile
- fine line and micro-ridge styli cause the least friction
- elliptical styli cause more
- conical styli cause the most
This is simply a function of the contact area of each stylus type.

Anti-skate - the higher the AS setting, the more friction

Arm height
- arm tube level = normal VTF = normal friction
- arm down at stylus end = higher VTF = higher friction
- arm up at stylus end = lower VTF = lower friction
This ignores changes in VTA/SRA and any effects they may have on friction, but it might explain why you have less tremolo on 200g records than on thin ones. If you haven't raised the arm by the thickness of the record, VTF will be *slightly* reduced and therefore friction will be reduced. (I admit, this is really a stretch.) If those 200g records are less warped than the lighter ones, that would have a larger effect.

Doug

HI doug and Raul

I have a new element:

I have found two screws to set up the AUDIO NOTE IQ 3 again with the rega turtable and the rega tonearm

I finally can also hear that the sound is no as straight than I thought before. It is MUCH MUCH lighter than with the Shelter or the DL 103 but it also has a tendency to produce little vibrations on the tonearm and to spoil the sound a little .
It sounds now ( with the IQ3) sometimes like" old records " what I thought normal before using the shelter .

To summerize my observations after one week

With the rega turntable / rega tonearm

The best ( the less bad ) combination to minimize the problem of vibrations is with the AUDIONOTE cartridge

Then comes the Shelter

Then the DL 103 wich is the worse

The combination Verdier/ TP / Shelter is worse than each combination above to avoid vibrations ( certainly due to the qualities of such an equipment) when records are not perfects .

Of course the Shelter is far better than both the AN and DENON in all other considerations when it is matched to the REGA .

Dear Andre: In essence my answer is: yes, but in practice if that low compliance cartridge is matched with the right tonearm almost never will have any problem with trackin a record.

One of my lowest compliance cartridge is the Ikeda with 5 cu and other than the Telarc 1812 I never had any tracking problem with any of the 3-4 tonearms where I try it.

It is curios that both tonearms: Rega 900 and the TP had the same problem and not with the Audio Note. It could be that both tonearms are out of specs, who knows. We have to wait for the new one.

Regards and enjoy the music.
Raul.