Turntable speed accuracy

I have just replaced the rubber belt on my Raven AC-2 with the Bavarian thread sent to me by Dertonarm ( thanks Daniel).
The speed consistency is slightly improved with this thread drive but the sound of the turntable has been somewhat transformed.
There appears to be a half octave of added bass together with an increased level of excitement and realism to each and every track and record.
Is there more to the drive method than pure speed accuracy?
When I changed to the thread drive, I needed to adjust the Raven motor controller to correct for the differing characteristics and I used the KAB Strobe to quickly get me to the 'ballpark'.
I then installed the Timeline and was shocked to find how inaccurately the platter was now running? I needed to press the 'UP' button about 7 times to reach the correct speed on both 33.33rpm and 45rpm.
When the speeds were corrected with the Timeline......the KAB Strobe indicated incorrect speeds!?
I know the Timeline is correct as it agrees exactly with the speeds on my Victor TT-101 which are quartz-locked.
Perhaps it is only my KAB Strobe which is faulty?.......but I urge caution for all those relying on strobes to set their speeds?
And for those who claim that speed accuracy does not matter.........how do you know if you haven't heard it? :^)

Halcro, interesting and thanks for sharing. What's very interesting is if you already had it set-up for accurate speed with the belt which I assume you did and by just installing the thread the variance.

Is the thread now longer then the belt size was? Not the same tention possibly?

Another tweak to try would be with your table is to use only two motors, have one motor on each side with separate threads but only one operational motor.

Are you not concerned with the thread maring the platter POD material? D mentioned someone else whom did this and it did such so this person has since moved onto using a 1/4 mylar belt and actually has the two motors set-up as mentioned above. Table being isolated separate from the motors.

I also have the thread on hand and my table being the TW BK with an almost all copper platter being mostly different than yours I'm concerned and have yet to do it, last thing I want to do is damage the looks of the platter.

On tables like the MS appear to be no issues due to the different plater material, gun metal or stainless.

Dear Henry, What about listening? When you set the table up using the KAB vs using the Timeline, were there any audible differences? If the KAB was that far off, on the slow side, you ought to have heard it in the form of pitch distortion and/or rhythm distortion. One would have to think that one of your two devices might indeed be defective. Either that or neither is quite accurate.

I had an interesting experience just a few days ago. When I originally set up my Lenco, I had it running at 33 rpm per the KAB strobe, with AC direct from one of my dedicated house lines. (You can adjust speed on a Lenco by moving the idler wheel up or down a tapered shaft driven by the motor.) Then I inserted my Walker Audio motor controller and had the Lenco set at exactly 33 with the Walker. Then some months later, I removed the Walker and was running direct from the wall socket again, but I had not re-checked the speed when I went back to house AC. The other day, I had an audiophile friend here listening with me to the Lenco, and he remarked that it sounded "slow"; he perceived a pitch problem. So we took out the KAB strobe again, and indeed, with the stylus in the groove, the Lenco was slow. I was embarrassed that I had not picked up on this problem. However, after he left, I realized that I had been bothered by the musical timing with the Lenco. Tempo seemed consistently "slow", but I heard no real problem with pitch. I had even wondered why Ella Fitzgerald had chosen a slow tempo for a Harold Arlen tune that I considered to be a good swing. The point is that what he perceived as a pitch problem was perceived by me as a timing problem. Obviously, tt speed affects both. I subsequently re-inserted the Walker and now all is well. The brain is a funny organ. He cannot sing to save his life, and I am a long time amateur jazz singer. You would think that I would have at least as good a sense of pitch as he does.

Dear Halcro,

your new experience with a thread driven Raven sounds good.
Next, you could try this:
- disassemble the three feet from both of your motor housings
- set up the housings flat on some kind of damping mat (a piece of anti-drone mat for washing machines would help)
- rearrange the strings

Now the motor housings are no longer able to wobble slightly on their feet (that's particularly the case when strong tension of the belt/tape/thread is applied). In my experience this has also positive effects on speed consistency and sound improvement.

Halcro great to see you trying the thread drive. The pulley shape should be concave for thread drive so it self centres and does not ride up and down.
Dev I have been using my thread drive final audio Parthenon for over 20 yrs with silk thread , surgical silk, quite high tension and there is only a very faint mark on the platter, no wear.