Audible Illusions Modulus 3A noise

@tubegb  

“AI preamplifiers are notoriously hard on tubes and sensitive to tubes that do not have a low noise floor.”

Your statement is grossly incorrect. Here is an L3A that is literally on more than it is off. Thousands of hours of usage on the tubes. No noise. Plus the unit was purchased used so who knows how many hours were on the tubes beforehand. 
 

One issue that occurred was a noise similar to a bad tube noise. The fixes, yes plural, was a cheater plug on my mono amps. Also one set of my RCA cables allowed noise into the preamp. Replaced that cables, dead quiet. 

Purchase tubes from a reliable seller it will be cheaper and the tubes will be just fine. Personally I'd go for NOS or good older pulls over current production 6922s. JAN/Phillips 6922's are typically a solid value. AI preamps have a ton of gain so they can really magnify a noisy tube make sure you get whatever you buy tested for noise.

That sounds like a bad tube. You can try cleaning the sockets and pins  first tho.

If you plan to keep your AI in stock form, I suggest only using Russian tubes, Sovtek or the 1975 Voskhod 6N23P.

Do NOT try any others especially not an NOS type tube.

I've been repairing and referbishing AIs for around 15yrs.

Feel free to email; hope I've helped.

I recently purchased a used Rogue 99 Super Magnum with phono stage. When I hooked it up I could hear static noise/hissing which was not acceptable. Before I did anything I replaced all of the tubes which were tested for shorts, Gm, and noise. These were purchased at a premium (only a few dollars more than standard retail). After warming up for 30 minutes I placed my ears next to a speaker and turned up the gain and volume to max. I couldn't hear a thing. Then I brought in my wife who has incredibly sensitive ears and asked her if she could hear any hissing, humming, buzzing etc. NOPE!!! I had the preamp connected to an Accuphase A-36 power amp and then to Fritz Carrera speakers. My signals input to the preamp were a Yamaha CD-S2000 and Thorens TD-1601 with Ortofon Cadenza Blue cartridge. That system as assembled is very quiet now.  

@wheezer1 I haven't done any cleaning & not sure exactly sure how to accomplish this, I suppose there are many YouTube videos with those details, do you have any tips?  Is this what folks use de-oxit (sp?) for?  what implement, like a bottle brush or special brush?

Thanks - as you can tell I've not done this before.

Kevin