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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
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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cmk
397 posts
 
It seems like Teres is following in the footsteps of Redpoint.
dougdeacon OP
3,338 posts
 
Sean, nice statement of the dilemma. It's one of those core conflicts that prevent "perfect" LP playback. Another such is the two contradictory demands on the tonearm. It is expected to hold the cartridge motionless above the groove, resisting all vibration induced by the stylus and cantilever, while at the same time following their lead to track a spiralling target. The better the arm is at one task the worse it must be at the other, at least conceptually.

Due to a number of design elements, the Teres 265 is highly resistant to vibration, including motor vibration. Therefore, as you say, closer coupling to the motor should stabilize speed by reducing stylus-induced variations. That was our experience. On other tables, YMMV of course.

Cmk, since Redpoint began by following in the footsteps of Teres, maybe they're both walking in circles! Of course going in circles is the goal, so I guess that's okay. :)
teres
120 posts
 
Sean, With a precision DC motor cogging and vibration are
almost non-existent so rigid coupling of the motor and
platter tends to deliver the best results. In general I
have found that less compliant materials sound better.

However, there is a small contingent of Teres owners that
prefer the sound of rubber belts on their Teres tables.
Exactly the opposite of my experience. I don't know why
this is the case. But I suspect that it has to do with
personal tastes and system interactions.

Use of magnetic tape as a drive belt predates both Teres
and Redpoint. However, the guys at Redpoint are the ones
that pioneered the use of 1/2" wide VHS tape. It turns out
that they were dead on about the virtues of wide tape.

I am in the process of evaluating a number of new belt
materials and still have not pinned down what type of
belt will be the standard Teres issue. The mag tape and
silk sent out with the 265 models is a interim until the
evaluation is done. Right now 1/2" wide decorative mylar
is what I like best. Better sounding and less fragile than
VHS tape.

Chris
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