Turnable database with TimeLine

I used to think it was "normal" for the pitch of a sustained piano note to waver up and down. (After all, my old AR did the same thing.) I thought it was some issue with the master tape, wow or something like that. Not!

 I am convinced that you can improve and stabilize a good turntable by the following measurements:

1) ensure you have separate isolation platforms for motor, table and flywheel

2) use a motor and pully which are in good condition and work absolutely stable (in case of older Micro designs maybe check, lubricate, exchange the transformer and/or capacitors)

3) better go for belts than threads. ensure the belts have the same distance and measure the belt tension. should be the same value for both belts

4) the VPI double motor driven by the SDS is one of the most   precise and stable motor/steering combinations on the market today

Dear Thuchan,
In principle, it might not be a good idea to mount motor, table, and flywheel on separate isolation platforms. Unless you also stipulate that said platforms should be identical in all respects and mounted on a common shelf. The issue is that if the respective platforms resonate at different frequencies, and/or if they are differentially isolated from environmental energy, then there is a risk that the motor and tt will move relative to each other. That allows tension or relaxation of the belt, alternately; not good for speed stability.

Why do you dislike threads vs "belts"? For a belt, do you recommend compliant or noncompliant? Thanks.

Thuchan, you recommend three separate isolation platforms for motor, table and flywheel. How can one control relative movement between the three? If they move differently, would that not effect belt/thread tension and thus effect speed?

A few posts above this thread discusses the early SOTA tables that have the motor mounted on a sub chassis which is separate from the platter, so they could move relative to each other and according to some users, this caused speed issues.

I had my turntable dismantled the last couple of days. I found some bushings at the hardware store that slip over the threaded studs supporting the main chassis. The sub chassis has holes for the studs to go through. These bushings that I found were 1mm smaller in diameter than the holes in the sub chassis. This made them a perfect fit. Where the sub chassis used to cycle up and down several times if pushed (underdamped) it now moves back to position in one cycle (critically damped). I was concerned that the sticktion was too much but using a level on the platter; the sub chassis seems to move back to the correct position every time. I have very good isolation of the whole turntable. I had developed the isolation last year which made a considerable improvement. That surprised me since the turntable is a suspended design and I thought was already well isolated.

I put my turntable back together and set it up to play this evening. After dialing in speed I started listening to some records. The iPhone app showed speed was off by 0.1Hz out of 3150Hz. WoW&Flutter at +/-0.02%. After dialing in 33 and 45 rpm I started playing some music. Right away I was bothered by the difference in the highs. I realized that they are cleaner now, which makes the highs like cymbals more apparent. It took me a couple of records to get used to them. The whole character of my turntable has changed. Nothing has been lost as far as I can tell. The soundstage is more airy. The detail and clarity of the highs are startling. Imaging is more focused. I can't say I hear a difference in rhythm and pace. I don't think speed was off by that much before. The improved speed control seems have affected more subtle things about the music. I have now experienced things that several people have said would happen with improved speed control. Constant belt tension even under micro conditions such as stylus drag is critical. I am a believer now.