Shelter and Triplanar matching ?

Hello.

What does the music sound like?

With the information that you provided, an acceptable resonance frequency for this combo is between 9 - 19 with 12 cm/dyne x 10 (-6) being ideal. Find out what the compliance is for the 901 to get an accurate measurement. It could possibly be a mis-match, ie tone-arm too light for the 901 or cartridge compliance too low.

Do check to see if the cartridge is mounted properly (screwed tight) and also check that the VTA screw on the Tri-Planar is tightened.

The ZYX line of cartridges would be a great match for your arm if in fact the Shelter does have a low compliance.

Hi dogpile

If you know the Triplanar can you tell me wich counterweight(s) I must use for a 9,5 g cartridge .They furnish 4 counterweights ( 1 big beveled and 3 smallers flats) .

Tenmus,

There is no serious mismatch between your cartridge and arm. The TriPlanar's nominal effective mass is 11g (varying slightly depending on which counterweights are used). A 901 with mounting hardware weighs approximately 10g and it has a compliance spec of 9 cu. To find their theoretical resonance frequency R we solve for the following formula:

R = 159/(SQRT((M+m)xC)) where:

M = effective mass of arm
m = mass of cartridge and hardware
C = compliance of cartridge

R = 159/SQRT((11+10)x9)
R = 11.57 Hz

This theoretical prediction was empirically confirmed on my TriPlanar VII/Shelter 901 combination. On the HFN&RR test record's resonance tracks I observed resonance frequencies of 11 Hz, + or -1. Not perfect but certainly acceptable.

You'll get slightly better bass and dynamics from your 901 by making the arm's effective mass as high as possible. To do this, use the bevelled weight (pushed all the way forward) plus the LIGHTEST donut-shaped weight that will balance the cartridge and give you the desired VTF. Using a LIGHTER c/w farther from the pivot INCREASES effective mass. IME the benefit will be slight but audible.

That said, I don't know why you're seeing visible shaking of the arm on non-warped records. I certainly never observed that in the year or more that I used my 901. Dogpile's suggestion to check the VTA tower set screw was a good one.

His suggestion to try a ZYX was also one I agree with, when you can. The TriPlanar is worthy of far better cartridges than a Shelter 901. A TriPlanar/UNIverse combination has proven synergistic and immensely pleasing for many people, including myself. Any ZYX from the Airy 2 upward will easily outplay a 901 on this arm.

Good luck,
Doug

HI Dogpile and Doug

First of all thank you VERY MUCH for your suggestions and PRECIOUS help.

Doug.

I cannot try right now what you advise to me because I had to send the TP back yesterday evening : the fine adjustment of azimut has been damaged by ANOTHER person (although it is a NEW ARM ????? )

I think It didn't have any influence on the problem that I descibed to you yesterday as the adjustment seemed to be visually perfect (the head shell was exactly in a horizontal positon )

VTA was perfectly tight (adjusted in a horizontal position) with the tower nearly in its highest position, as the armboard on my new Verdier is very low compared with the platter position.


I had the same problem ( in lower proportions) with the same cartridge and my Rega RB 900 wich was my previous tonearm before using the TP wich I received only last saturday. So I was also thinking it could be also a problem with this cartridge itself ( breaking in or anything else ...)

So I'll follow your advices when the TP is back wich I hope the sooner as possible (???) and I 'll give you news at this moment . I am afraid it's not tomorrow morning !!!

Thanks again

André