VPI motor - upgrade to 300 rpm?

I get quite correct 33 rpm (a tiny bit slow) by setting the SDS to 66.00 hz, the top value, and then position the player (or the Samas, but that is harder to do) so that the nylon thread gets a good amount of stretch. The thread is 1 mm thick. For 45 rpm, I get OK speed at 90.00 hz (note, I have 230volts/50hz electricity), although I hear some hum from the motor.

Storyboy, I notice you use a rubber belt rather than a thread in your flywheel system, is this because it sounds better in that configuration? Could you describe the change the flywheel makes to the sound? Is it possible to order the flywheel as a separate part?

Podolaw, thanks, I will check out.

Mike at VPI writes that changing capacitors will make a difference to motor performance:
"The 600 RPm motor should work perfectly when you get the capacitor right for your countries voltage and frequency, it is a critical item and if you are willing to play with different values you can fine tune the motor for lowest noise and running smoothness.
Begin with .22 microfarads and work your way down in value till the motor stops running."
Have anyone tried?

O_holter, I did this with a new Hurst motor for my AR table. Not a VPI but it does use a Hurst. I did indeed get lower noise and smoother running by experimenting with lower cap values. But there is a price to pay. If you go too low you run the risk of having the motor randomly start rotating in the wrong direction on power up. You'll have to give up a bit of the lowest noise performance you can get (by upping the cap value from that point) to get reliable start up direction.

By a variety of Sprague "Orange Drop" caps up to just below .22uF and they each one out until you get the best compromise (.047, .1, and .15 are available). Use the 716P series.

Tonyptony, thanks a lot. I am a bit confused by looking at the Hurst and Elusivedisc web pages. From the latter it appears that VPI is upgrading towards the lower rpm hurst motors, and that the 250 rpm motor is currently the best regarding low noise, but perhaps it cant be done with the hw-19. I have mailed them, is this correct, and if so, what is the reason (pulley too large?). I'd like to get the best motor in place before other things (pulley size, string type, capacitor type).

Rubber belt alternatives - debatable?
From my experiments so far, using nylon and silk thread versus rubber belts (vpi new grey + translucent original belts), it appears that rubber has a number of good sides, that are only with difficulty improved by the thread solutions. Two nice sides with rubber is fairly robust performance regardless of platter - pulley distance (within limits, not very demanding of setup), and a fair degree of "body" and overall tonality to the music. Even if thread solutions are a step up, if set up right. Silk thread sounds a tiny bit better, I think, compared to nylon, but may be a bit more troublesome also. When things are right they sound better than belts, but they have to be tensioned "just right", and with the VPI Samas arrangement this can be a bother to adjust manually from time to time (more often than with the rubber belt). Possibly the ideal arrangement would have a light spring arrangement pushing the Samas away from the platter to "auto-tension" the thread.

As others on A-gone and elsewhere have noted, this concerns the right balance between stiffness and elasticity, transfer and isolation. We want motion going one way, but no audio noise, and nothing travelling back either.

The more the platter is able to overcome motor and pulley and string weaknesses (noise, pitch variance, statics) by its own momentum, the better. The ideal self-moving platter hasn't been invented. VPI currently offers a very expensive "hrx super platter" upgrade, this is probably a great benefit, but I have gone through three VPI platter upgrades already, and guess my current Black knight platter should do the job fair enough for awhile, there is more benefit to be had by motor tuning and drive adjustment. A direct drive for HW-19 is not available, but a good thread solution is said to be a step up in the same direction.