Audible illusions Modulus 3A or Klyne 6L

I've had the M3 and M3A for about 13 years combined. Only retubed the M3A once to improve the midrange. Installed Amperex Bugle Boys and they made a tremendous improvement. Blows away the standard Sovtek's by a significant margin. Not sure you can beat the value this preamp delivers at the prices here on the 'gon.

Absolutely NO WAY to know what will work best for your whole system. Check the specs and go from there. Looks like the AI is winning here hands down so that's something. For my money I went a different route -- passive TVC -- and haven't looked back. Value is off the charts -- but you need to make sure the impedance match will work.

Compared to the other active pre's I've had, there's no contest for transparency and the 'you are there' experience. FWIW

I have owned a Modulus 2D and a Modulus 3A. I had NOS Siemens-Haske in the 2D
tor 3 years, and switched them to the 3A for the the past year when I upgraded. They STILL sound great and test strong.
From my own personal experience, I think this tube eating thing is overblown. I mean, it gives the impresion that NOS tubes will last 5 minutes in a Modulus and then explode. I can attest to the fact that if the tubes are strong from the beginning there is a good chance they will
last.
Andr, do you have any personal experience using a Modulus?

Yes,

A couple of listening sessions at a local dealer plus one of my best buddies at the local audiophile club association in 2005 and 2006 had one. Heard it many times. Fine playing machine. I particularly loved its soundstage and overall 90's sonic presentation. He had the tube burning problem so he got rid of it before his NOS collection was wasted furthermore on it. Combined with all the litterature available on the subject, even one written in Soundstage by a reviewer, has fairly convinced me there is problem there. Good for you guys if you did not witness any of it.

The local dealer liquidated the line two years ago, although not due to reliability problem, anyways he won't say, but too much competition for AI in the same store. Modwright, Hovland (now out) and Chinese tube gear were too much for AI to survive.

Joe's tube Lore, although written in 1999, was quite clear and offensive on the matter. I fell on other comments about the AI problem, a few months ago, from a well known tube dealer which I'm looking for to add it here. Quite virulent. So 1+1+1+1 equals something. I'm kinda a zero problem, all reliability of an audiophile. This is a pricey hobby. There is a lot of choice out there, at all price levels. I prefer to leave aside a fine playing unit if there is a tiny little bit of controversy about it. Especially if it is openly documented by a lot of different sources.

Like I said, AI is the only one, the only one, which has openly been targeted by a lot of people, ranging from reviewers, tube dealers (of course)and users about tube life problems. I don't know about the exact source of the problem. That's the first time I hear it is because the tubes are still lit when the unit is powered off. Now seriously, please tell me if you know about any other tube preamp manufacturer that have such a design in their products. How come ?

AI Modulus Preamps Are Not Hard On Tubes... To date we have mfg.many thousands of these units and, to the best of our knowledge, premature tube failure has not been a problem. The problem is some "tube rollers" continue to substitute old-style 6DJ8 type tubes in our preamps. These tubes were OK for TV sets and RF applications but not designed for audio purposes. Thus the small plates and weak mica insulators resulting in excess microphonics and noise. However there do exist some NOS brands that are acceptable and exhibit good life; Tungsram is one brand that comes to mind.

Be advised that our tube preamps are open-loop/no-feedback designs. The advantage of eliminating negative feedback is well known. The downside is that the tube we select must be well constructed, have low-noise and good life. In our 30 years experience the best tubes we found that meet our criteria are those mfg.in Russia. In the early 1980's we did use some 6DJ8 tubes produced in the 70's that were well made but, when the supply of good tubes ran out, in 1987 we discovered Russian tubes. Primarily used for their military communications, including transmitters in MIG jets, these tubes were designed for low-noise spec.and reliability. All of our preamps since 1988 have Russian tubes installed.

Regarding our filament-on design, based on his experience with tube equipment in the recording industry, my boss had learned that the main contribution to tube failure was thermal shock to a cold tube. For that reason most recording studios left their tube equipment on. Of course, leaving tubes on does cause premature plate degeneration but he experimented with leaving the filaments on but with some current flowing on the plates. This design has proven to be a big success in prolonging tube life in our circuits.
Unfortunately this circuit design will not prolong the life of old-style, poorly made tubes. Suggest you tube rollers experiment with preamps employing negative feedback and cathode followers. Regards, Jerry/AI's Tech,