VPI rimdrive squeaks

Hum and squeak are unrelated phenomena, as you seem to know. Hum with phono reproduction is usually a matter of grounding. First try grounding the turntable metal chassis AND the tonearm to the preamp. Make sure this is a firm connection; I like to use bare wire and scrape any paint or other finish off the chassis in the area of the ground connection, so that the wire really is crimped against the bare metal of the chassis. If you have done that and still have hum, then disconnect one or both grounds from the preamp and see what happens. Another more rare possibility is that with your table the motor is close enough to the cartridge so that its EMI radiations are being picked up. Try shielding the motor in that case. This is a totally solvable problem.

As to squeak, since you have now heard it with two different rim drive motors, I am kinda stumped. Like others say, be sure the rim driver wheel is plane parallel to the platter surface and perpendicular to the driven edge of the platter. Since the squeak is in synch with the drive wheel rotation, examination of the o-ring where it contacts the side of the platter is in order, as others have said and as I mentioned before too. Sorry, you are getting the same ideas from everyone over and over again.

OK everyone. Really big thanks for all your input. It HAS moved me forward, sometimes not as I suspect you intended but by what you said in passing or implied. I’ve (re) tried checking the minimum contact pressure plus required horizontal and parallel geometries. I’ve lifted the O-ring out of its groove and tried at length to ensure it is sat back in there with no twists or other misalignments. (No difference, whatsoever).

I’m now going to hope my old-style black O-rings don’t have a uniform cross-section &or because of their outdated composition can ‘creep’ along the rimdrive groove they sit in. No idea if that’s correct but it’s top of my list to at least eliminate by replacing them with the latest rust coloured rubber.

As to the Historical Humm. It was not an earthing issue. I have a depressingly thorough matrix of all combinations of earthing configurations which made no difference - as well as isolators and couplers under the motor assembly WHICH DID – and noting the (very) different levels of Humm with each. The worst caused my more rigid (non-stock) power cord between motor and SDS to vibrate and feel as if water was running through it. Even the SDS vibrated. Depressing and thorough matrix may be available if wanted. I personally believe it was so comprehensive it convinced VPI that I was a nutcase. It clearly took a lot of thought, time and effort to obsessively create (because I thought I was alone with this problem. See below.)

I got rid of the Humm by believing the Symposium platform guys. Symposium believe things which vibrate should be coupled to their platforms (or somesuch) which absorb and dissipate that energy. (Hence their Couplers...) Isolating and feeding it back is the worst thing you can do, by which they include the new soft rubber feet on the VPI motor assembly as NOT the best way to go [ but of course VPI can't assume evryone is sat on Symposium or equivalent ]

My old VPI motor assembly had the old aluminium feet with sticky disc squidgy inserts – as a forerunner of their big soft rubber feet. I removed the inserts and allowed the aluminium feet to directly couple with the Symposium platform so it could do its job. Humm disappeared. Totally.

What I think remains the case is the motor assembly still inherently vibrates but the platform absorbs sufficient of it to stop me hearing anything. Probably some residue makes its way to the platter and the cartridge (Stringreen !).

I read in another Humm thread that someone had solved the Humm by placing the motor on Symposium Point Padz. I independently tried that in the early days of diagnosis. For me it enhanced the Humm wonderfully. Don’t know why but can take a stab at the Point Padz not having enough absorbothingystuffness and actually isolating from the main benefits of the Symposium platform.

Who knows.

A basic suspicion behind all this is – VPI must be sat in the middle of problem feedbacks (as are all manufacturers) – whatever small or minute percentage of total units it comprises. I can fully appreciate they wouldn’t want to take a recall hit like Toyota is planning – but I’d be grateful if they didn’t work so hard at making the sufferer think they were the only weirdo with the problem and therefore THE PROBLEM. Not easy but I think do-able.

I’ll let you know how the rusty O-rings fare.

Hiendmuse...isn't that odd....VPI changed to the rubber feet on the motor assembly from the solid metal original ones to allow the motor assembly to slightly rock so as not to transmit any out of roundness of the rim drive to the platter. You're saying the pointed solid feet are an improvement?

Rateourmover,

If all else fails, try oil/grease change on both platter and rim-drive spindle.