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TT drive belt comparison

Hi folks,

Last night and today we A/B'd the two drive belts that came with our new Teres 265. One is the standard silk string as explained on the Teres web site. The other is a 1/2" wide length of spliced magnetic tape. Chris Brady is now supplying a 1/2" high motor pulley, at least on some models, and is testing a variety of belt materials.

SUMMARY: the magnetic tape beats the silk string very handily

Why? Because the tape provides better speed stability. The audible differences are at the micro-detail and instrumental/voice timbre levels, but they are clear and entirely in favor of the tape. The tape significantly reduces the time-smearing of notes, making the whole system sound faster and cleaner.

Soprano soloists and choruses are notably clearer, cleaner, better differentiated, less shrill, less sibilant. Very high-pitched organ notes are far less smeared or distorted, as is every note and overtone on that notoriously difficult beast, the harpsichord. The voice of a bowed cello or bass is weightier and more authentic because each vibration of the string is now clear. Individual voices in the orchestra are more individual, less mushed together. Nearly all attacks are quicker and weightier.

I could go on but you get the idea. If your Teres (or other TT) will accomodate a tape rather than a string or rubber belt, I recommend you try it. It's fussier to set up. The motor and platter must be levelled exactly the same or the tape will crawl off the pulley. I shimmed the cups beneath our motor spikes with varous thicknesses of paper and now the tape stays in the center of the pulley.

Good job Chris!
dougdeacon

Showing 2 responses by sean

sean
6,231 posts
 
Belt drives are a tough call. If you have increased coupling between the belt, drive pulley and platter, you have greater speed stability due to less slippage. At the same time, increased coupling / reduced slippage also results in greater transmission of vibration from the motor / drive pulley and the platter. Obviously, one has to draw the line somewhere. Personally, i would rather have consistent speed and design the table to properly deal with both internal and external vibrations. Sean
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sean
6,231 posts
 
A wider tape or drive material should:

1) spread out the vibrational load introduced to the platter that originated with the motor in a more consistent manner

2) help to damp air or platter-borne vibrations due to the increased contact area of the tape with platter

3) offer a greater contact area for improved power transfer with less slippage

4) cause less "walking" of the spindle within the shaft resulting in greater pitch stability

5) reduce eratic bearing wear

Sounds like a "win/win" situation in "theory".

How does one go about sizing the tape / mylar and attaching it to itself once cut to size ? Sean
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