SME 20/2 Finger Lift Hum

Hi Larry, That's what I originally suggested - insulate the arm lift OR don't touch it. If the system is elevated from true ground for some reason, for example due to a faulty wall socket, it is conceivable to me that one's body could be at a lower potential. When you contact the arm, only then is there a loop. There are several variations on this theme, but I hope you get my idea. The body as antenna usually results in a higher pitched noise, not true hum.

Also, if the tonearm is grounded to the phono stage, as someone else suggested, it might be of interest to un-ground it. If we then don't have hum, my hypothesis is supported. Anyway, changing the current grounding scheme, whatever it is, might reduce or enhance the problem, and that information would be valuable.

All grounding effects have been tried (on the SME there are three into two grounding cables from the arm). None, either one, both. No change. Checking additional items, there is no hum (and it is a hum, not a high pitched sound) at the arm tube, headshell or cartridge body. But there is at the finger lift, tops of the headshell bolts and the front bolt on the Lyra. For now, have insulated the finger arm with plastic, but would like a permanent solution. That could be a new cartridge or replacement of the stainless steel bolts/screws with non-conductive bolts/screws (nylon or carbon fiber?). Has anyone tried that and if so where to procure? Thank you.

Unless I have completely misunderstood what is going on here (and that is entirely possible), I don't quite understand why you are so exercised over it. If insulating the lift has cured the problem, I especially do not get it. I would think of that as a "permanent solution" and go on from there to enjoy the music.

For example, my dedicated MM phono stage will put a low level buzz on my speakers, if I don't dress the umbilical cord from its power supply so as to be clear of the AC cord. So I taped it up to stay away from the AC cord. I consider that "case closed", but the reality is not unlike the one you describe; I used a bandaid to fix a problem. So what?

If I understand the situation, this was NOT an issue with a prior cartridge, but, it is an issue with the Lyra Argo. If that is the case, it may be the case that the Lyra's aluminum body is part of the conductive pathway. In that case, you may be able to do something with plastic screws, but, depending on how conductive is the headshell and the body of of the Lyra, you may also have to put some kind of barrier between the cartridge and the body. Keep in mind that the Lyra body is designed to make a very tight physical contact with the headshell in order to effectively drain vibrational energy from the cartridge into the arm for dissipation by the arm. That "insulation" might compromise that objective.

In short, I would go with Lewm and consider insulation of the armlift as a permanent solution.

It's certainly a workable solution since it's what I am doing and when actually playing a record it sounds fantastic, but I will still be experimenting until I find a 'permanent' solution. The concern about the tight and rigid coupling with the Lyra to the headshell being compromised is a concern of mine as well if nylon screws are used. Thanks for all the advice. We'll see where this goes.