VPI Classic hum

I was told a separate ground wire is required for Grado cartridges not to hum, I've used a wood-bodied Grado with an Amari TT mounted with Rega RB250 arm, but with separate ground wire (unlike Rega TTs), and no hum heard.

My Classic has a steel arm-tube, btw ...

Damn, it shouldn't be so difficult to get it all right with the Classic. My previous Clearaudio Performance was much more well-behaved! Yet, there's something about Mary, er, I mean, the Classic ...

Bassraptor, which Classic model do you have? The Classic 1 and Classic 2 come standard with the JMW 10.5i SE arm, which per the VPI website is "made from aluminum and stainless steel, critically damped in the armtube to keep the arm and wires from vibrating." The VPI website says the Classic 3 "arm [has] a new stainless steel arm-tube, bearing assembly, base mounting, and Nordost Valhalla wiring from cartridge to RCA (or XLR) output jacks."

As I mentioned above, Mike is suggesting that I try an arm tube made of stainless steel. Perhaps it's the same arm tube you have??

In any case, I would appreciate knowing which model Classic you have and whether you have identified any compatibility issues with the Classic/Maestro combo. Thanks for your help.

the hum comes from the motor, and an unsheilded cartridge. No armtube, cables, or anything else is going to make a difference. With the motor in the plinth, you need a different type cartridge, well shielded.

Not a fault, just a design quirk, that means you need to use a certain type cartridge to get the absolute best sound from the deck.

Bifwynne - I have a Classic 1, it's about a year old; upgrading the armtube to steel was an option I paid extra for. There's no compatibility issue with the Maestro that I can make out so far, but that hum is still there! As Macdadtexas said, it's the design quirk ... odd that I initially never noticed it a year ago ... getting a Soundsmith is going to be another expensive trial.

Need to reassess things the next few months ...

Bassraptor, very curious, very curious indeed. As mentioned above, I installed a Maestro Wood cartridge on my Classic 1 with stock arm. I may be hyper critical here, but I think I detect a bass resonance or ringing in the 50+ to 100+ Hz registers. I surmise this because I still detect the bass bump when I turn off my sub, which rolls off at 40+ Hz.

As also mentioned, I've been trading e mails with Mike at VPI about the issue. I infer from his messages that he may have been able to replicate the bass bump at the factory. He suggested that I exchange out my stock aluminum/stainless steel arm for an all stainless steel arm. Mike explained that the stainless steel arm has a higher damping factor and effective mass. My questions back to Mike were (i) a request that he confirm whether in fact he was able to replicate the bass bump using the stock arm and (ii) if yes, whether the stainless steel arm corrected the problem. If the answers to the foregoing questions are "No," I may have to rethink what to do next.

Oh BTW, I believe the bass bump relates to the phono stage because I do not detect the bass bump when using my CDP.

Perhaps you can help me with my issue by telling me how you set up your cartridge. In particular, (1) did you use the VPI jig to set alignment and overhang? (2) At what mass did did you set VTF? (3) How did you set VTA/SRA -- with the back end of the cartridge above or below a straight horitontal plane for the cartridge? (4) Did you use a head shell weight? (5) Did you use the VPI mat, rubber damping ring and clamp. (6) Finally, I assume azimuth was true.

Now, as regards your problem, maybe my ears are just plain shot after obsessing endlessly over my perceived bass bump, but I do NOT detect any humming coming off the phono stage -- just a little tube hissing, which is normal. My rig is an ARC PH-7 phono pre, an ARC Ref 3 line stage and an ARC VS-115 amp. I have not as yet hooked up a ground wire from the Classic to the PH-7. The I/C from the PH-7 to the Ref 3 is nothing fancy, just a set of better grade off the shelf Auvio brand RCA jacks I bought at Radio Shack. The I/Cs from the Ref 3 to the VS-115 are balanced Kimber Heros.

It seems to me that we have similar TT set ups. Logic dictates that if we conform our set ups as much as possible, perhaps we can help each other sort through our respective TT issues. I gather you have suffered through I/C problems, grounding and proximity of the I/C cables to inductive current lines. If so, the only thing remaining is that your Maestro may be defective or, perhaps more likely, the stainless steel arm in some way is creating an induced electro-magnetic field because of proximity to the motor. Remember, my stock arm is a combo of aluminum/stainless steel.

Last thoughts, did you mention above whether you think the hum is at 60 Hz? If so, that would be a strong pointer to the motor and stainless steel arm. Have you contacted Mike at VPI, either via e mail or phone?

Sorry for the long post. Just trying to help.

Please write back with your thoughts. Thanks.