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VPI Rim Drive vs. belt drive sound files

Greetings All,

About two weeks ago I installed the VPI Rim Drive on my HRX turntable. Having gone through the same frustration of getting the speed stable discussed in other threads, I ---> THINK <--- I finally have it fairly well tweaked. The difference in sound appears to be a much more focused sound stage at the expense (?) of a change in tonal balance. Specifically, the mid tomes of piano keys seems to be a bit more harsh and there appears to be a bit more extension in the very bottom octave.

As I use my turntable purely as a front end for archival capture and mastering, I have digital files of the same tracks, though the identical signal path with both the belt drive and the rim drive. If anyone has the patience to download these large AIFF format files, the link below will give you access to a few of them. I’d be very interested in getting feedback from all on both sonic differences between them as well as any suggestions to improve the Rim drive set up based on listening. If you’d like to check them out please go to:

http://clients.crossroadstelevision.com

user: dean
password: marvin
go into the “VPI RIM DRIVE TEST” folder

Cheers,
Dean
dean358
tfkaudio
591 posts
 
I was having speed stability issues with my VPI. The problem was that the belt on the circumference of the rim needed to seat itself properly after being installed. Once seated, stability got better, but was still not perfect due to the fact that the diameter of the belt itself was not identical at all points and did not have enough "give". VPI has since changed the feet on the dual motor assembly to rubber feet, and came out with a new belt that has more give. Once you've made those upgrades, your speed stability should be excellent.

A couple of notes:

I believe VPI will supply the new feet and belt free of charge to customers with the rim drive.

I also believe the SDS is nearly mandatory for rim drive users, since the speed setting on my SDS is WELL below 60hz. (Like 59.40) If dead-on 33 1/3 can be accomplished without the SDS and WITH the rim drive, great. But I really can't see how.

Cheers.

Tom
ptmconsulting
1,000 posts
 
A couple of suggestions for those of you with belt drives but interested in getting more PRAT out of them.

If you look closely at the belt where it comes off the spindle before going back to the platter you will notice that it wobbles quite a bit. You can feel it easily with a finger lightly touching the belt. Try placing something heavy and smooth up against it to reduce this "rumble" and vibration. I bet you will hear a smoothing out and a more stable musical presentation.

Another suggestion is try using string instead of the rubber belt. You MUST have a speed controller to do this though because the width of the belt ve the width of the string will cause substantial speed differences in the platter. Use a string that does not stretch, like Rayon. This proved to be a substantial improvement over the VPI rubber belt, even with the stabilizing buffer on it.

I would love to see how much better the rim drive is over a string drive. I'm sure it would be a closer contest overall.

Happy New Year,
Bob
dgarretson
2,588 posts
 
"I would love to see how much better the rim drive is over a string drive. I'm sure it would be a closer contest overall."

Or possibly worse than string, in view of the fact that VPI's implementation of rim drive retains several soft rubber belts.
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