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.
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 Ill 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 thats 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 Im 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. Ive 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.
I guess I should add that the reason I bought the M3A, is that I plan to get a turntable at some point in the near futur and wanted to have the flexibility at that time, so for now I'll just use the line stage.
Are there any good resources on the web besides Upscale Audio to source tubes?
I own a AI M3A and i haven't had any tube eating problems although I do use a pair of pearl tube coolers on the line stage tubes. This preamp has a pair of switches that drop the gain down it could be that only one of the switches is set to low gain and that the right channel is still set to high gain so your system has too much gain on that side which causes a lot of hiss depending on the system especially if you have a solid state amp. I would check this first since it would cost nothing to fix if that were the problem.
Opiv1: Thanks for the response, what kind of tubes are you running with sucess? Also, are the gain switches inside the preamp?
Thanks for the help.
M3a phono section will not suffice for the descent analogue setup.
Much wiser investment will be for AE3 and separate phonostage such as EAR834P. Alltogether you gain performance on both linstage and phonostage sides.
The M3A has an excellent phono section. Don't let anyone tell you otherwise. Is it the best, no. Is it good enough to build around for an excellent analogue system, darn straight.
Your hiss is the tube in the channel making noise. AI has had some tube issues (all Sovteks are not created equal). I have used these preamps for years and currently use an L-1. I bought a pair of "Rocket" tubes from Upscale Audio for $30 each and they sound excellent and are really dead silent. I also bought a pair of matched Sovteks from AI which are also dead quiet. I went through a bunch of noisy Sovteks a while back with a M3A. Other tube brands will work but be real careful where they come from. AI has a recommended tube list on their web sight. Check it out.
I use the L-1 with 3A Sigs. It provides top notch performance as did the M3A.
I'm basing on my experience as well that the IMO combo of two AES3 and EAR834P will perform far more superior than one M3A.
Moreover EAR can be fed directly to the amplifier since it has volume control which gives an extra flexibility for the same amount of money.
Nice system. Don't fear tubes. Try switching sides to see if the hum follows. If it does, buy tubes! They are not so expensive-avoid crap (sovtek is crap). Try these sites:
www.tubesandmore.com www.thetubestore.com www.upscaleaudio.com www.jeffssoundvalues.com
Find a local store with a tube tester if you are curious or send them out for testing. All it will cost is shipping.
Marakanetz, Everyone is certainly entitled to there opinion. After dealing with audio for over 35 years, I have found that a lot of components just present a different presentation. Better is in the ears of the listener. The M3A is capable of outstanding phono reproduction as verified in all of the positive reviews over the years by leading mags. My experience concurs. It is extremely neutral for a tube based preamp. It is also a hell of a bargain on the used market.
Thanks for all the feedback everyone. I switched tubes R/L and the hiss followed it, so it appears it is a tube going bad. Everyone talks about how hard the M3A is on tubes, and Kevin @ Upscale Audio claims that my preamp would destroy a pair of Siemens or Bugle Boys inside of a week. Anyone have experience with this? If so, are there good sounding options other than Sovteks? Thanks again.
Bigtee - what kind of source componentry are you using?
I'm running a L-1 with a 4-ch Theta Dreadnaught biamping a pair of Vandersteen 3A Sigs. I use a Meridian 508-24 for CD sources.
You can pick up low noise Reflector 6h23/EB's from ATSI Tube for aprrox. $45-$50/matched pair (not certain of the current price). They are dead quiet and work quite well in the 3A.
I tubed my friends 3A with ATSI's in the line stage and Siemens 7dj8/PCC88's in the phono stage, over a year and a half ago (both pairs are still going strong).
I no longer have a source for the 7dj8's, but two matched pairs of the ATSI 6h23/EB's will also work.
yes the gain switches are in the preamp. I am running amperex bugle boys. You will need to make sure that you are flipping the correct switches because there are 4 switches two for the gain and two that are for by-passing the capacitors.
Well I think you got bad info on the bugle boys because mine have been in my M3A for 2mos. and still sound as good as the day I put them in. I do use a set of pearl tube coolers, also I leave the pre-amp on at all times. I also have had success with telefunken tubes, but I thought that the bugle boys sounded better. just MO
I guess I should list my system
SONY X779ES - CD
AI MOD 3A Pre
MCINTOSH 2100 Amp
Montana DPS Speakers
Stealth Audio Solid Silver interconnects
Magic Power Cord
Panamax Line Conditioner