Audible Illusion L1 / M3A, which tubes ?

I also had Electro-Harmonix 6922 tubes in my Audible Illusions L1 preamp and wanted to upgrade them. If you do a little reading you'll find that many say that Audible Illusions preamps are very hard on tubes and finding ones that both sound good and don't quickly burn out can be difficult. Spending hundreds of dollars on a pair of Mullard's that burn out in a month would be very disappointing.

I spoke with Andy at Vintage Tube Services and he told me he's sold lots of tubes for AI preamps and could only recommend two or three that he was confident wouldn't burn out. He recommended a pair of Matsushita 6DJ8 which cost about $75 for a matched pair. These were a pair of his "Andy's Perfect Picks" which are used but test 85-95% of new. I've had the Matshushita's in my L1 preamp for over a year and they are much smoother than the EH6922's. I can't say they are the end all in 6922's, but they are a nice improvement that won't burn out at a reasonable cost. I think these are listed as tube #8 as a AI recommended tube on the Audible Illusions web site.

Give Andy a call to see if he has any in stock or can recommend another tube.

Keep away from the Mullard re-issues. I didn't find them nearly as nice as the originals.

Also remember that a good 6DJ8 will last around 10,000 hours. So if you consider a $100 investment, it's only pennies per month to use.

Art Ferris now uses the Russian 6H23eb tube in his newer M3B preamp. Many M3A users use this tube as well.

It really comes down to the fact that this pre amp requires a voltage at the tube plate that most NOS or common 6DJ8, 6922, 7308 types cannot handle.

Many fine NOS types or current 6922 typically have plate voltage ratings of anywhere from 95 or 110V, and even some have over 135V. The problem is that AA will burn through these in short order if used, despite how nice the sound may be.

The EH 6922 can handle the requirement and the best tube Iv'e personally found is the 6h23n-eb labeled Reflektor or Russian 6H23P-ev labled with Russian military code.

They were made in the former Soviet Union and are from the 80's typically. This tube has a plate voltage rating near 300V, thus it will endure and last in these pre-amps. They also sound very good and IMO better than the current EH (type 2) offering an even warmer and bigger soundstage. The best part is how inexpensive they relative to NOS types.

FWIW.. I have tried the Cryo version of this tube, but prefer the stock 6h23N-eb tubes sound.

Just report back to the folks here. During the last few weeks I tried the Reflektor 6H23N-EB and the Sovtek 6922 (the new but discontinued ones, not NOS).

As of now I'm staying with Sovtek after the comparison. The Reflektor is actually very good but I find it a bit too fast too aggressive for my taste. The Sovtek seems to be just righe for me. Very smooth and sweet.

Now back to the music...