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