Need help w/ Audible Illusions M3A

I don't own one, but a couple of friends, have or do currently.

Rumor has it that these units are TOUGH on tubes.
What you are hearing is most likely a tube issue, if it is constant. If the sound only occurs when the right volume knob is being turned, it might be something else, like a bad pot.
BigTee is a good guy, and he has Vandys, and a AI pre, and he has dealt with AI's service dept before, so he might have some pertinent info.

If it were mine, I would, unplug it, open the unit, swap the tubes from right to left, and if the noise follows the tubes to the left side, well, you've found your bad tube(s).

I cant remember if the M3A uses one, two or 3 pairs of 6922 tubes, but either way, NOS ones are NOT cheap.

I think Electro Harmonix makes these tubes now, and, again, if ti were me, I'd check out Kevin at Upscale Audio (now there are other tube sellers, sure, but I like to get things FAST, and like Kevin's knowledge and testing).
He can probably suggest some other alternatives, and I am positive that he has retubed AI stuff before.

Anyway, I'm not speaking from experience, but I've read on this site, and heard from friends, that AI's support might be hit and miss.

So it may be faster to order replacement tubes from a source other than AI, but again, I'm not speaking from personal experience.

One thing is for sure, they make a helluva preamp.
Good luck, and I'm sure there'll be many many more responses, once everyone gets off work.

Joe

Sell your M3a(since you don't need phono section) and opt for AES3 that costs twice less new than M3a used.

Less tubes required to replace(only 2) and NOS will last forever in there.

The following is directly quoted from Joe's Tube Lore (I have never owned an AI)

The 6DJ8, 6922, 7308 Saga - Part 1

Posted by Joe S on March 29, 1999 at 19:59:08:

Well this time I’ll be reviewing substitutes for the ubiquitous Sovtek 6922. That means it is time for 6DJ8s, 6922s, 7308s and a few other odds & sods thrown in for good measure. Once again all the usual caveats apply, so here we go!

Special warning to Audible Illusions preamp users:
The one you can say for the Sovtek is that you can run it hard and it can take it - and apparently that’s exactly what AI does. Unfortunately the classic NOS tubes in this family just cant take this kind of treatment and will rapidly fail when used in these units (and some of you guys have the fried tubes to prove it!). So you AI users are probably best off limiting yourselves to the Sovtek, the Russian 6H23N & 6N1P, the 7DJ8 and the E288CC. There may be others the range of tube types and variations is quite literally bewildering but these are the ones I’m aware of that should be able to handle the higher stresses of this brand of preamps. I review the Edicron, Siemens E288CC and 6H23N here but there are other brands for some of these. I’ve seen Phillips E288CCs & Amperex 7DJ8s advertised on some web sites in the past and there are probably others. It might be worth your while chasing them down & evaluating them for yourself to increase the number of alternatives for use in your AI.

Marakanetz made a good point -- you're wasting 2 tubes since you don't need phono playback. How about replacing it with the L-1!

I'm new to tube gear as well -- I own the AI-2D. The hiss could be early stage of tube failure, noisy volume pot as mentioned above, or it could very well be RF interference. I experienced all of the above.

From what I understand, the latest (3rd+) generation Modulas preamps don't run the tubes as hard as the previous ones. I'm using russian 6H23N-EB, Mullard 6DJ8, and Amperex Orange globe with good success in my 2D. JAN Philips and Sylvania 6922s died within 2 months though. I was told that the 188CC/PCC88/7DJ8 tubes, though rather scarce and expensive, are good for the AI phono stage as they have higher tolerance (can't expand more on that). I'd stay away from the 6N1P unless advised by the factory.