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Tubes for Audible Illusions Modulus 3A?

I have an AI M3A from around 1995 that seems to eat tubes on a regular basis. I got it used in an A-Gon purchase,it had stock Sovtek tubes,which were clearly past their prime. I've since tried some Electro-Harmonix 6922's,which developed noise very quickly,some Golden Dragon 6DJ8's which lasted a bit longer,but now one is hissing away in the left channel. Should I bite the bullet and pay AI's ridiculous price of 35.00 per tube,or has anyone had good experiences with alternatives for less money? Thanks. Bob LaBarca
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imin2u
392 posts
 
I've been going with NOS tubes and they've lasted years. I have a pair of JAN's that are still alive after two years.

The big question is "Do you power off the M3A or use the stand-by mode?" I don't. I leave everything on all the time. All The Time.

My cdp has been on 5yrs and has never had a problem. Electronic gear doesn't like powering up and down.
jcus
26 posts
 
Audible Illusions advises caution when using NOS tubes in ours or several other mfgs open-loop no-feedback circuits. Also the 6DJ8 design was never really intended to be used in high performance audio circuits. They worked great in TV sets and oscilloscopes but they tend to be microphonic due to their small plates and thin mica structures. Most 6922 tubes have heaver mica structures and exhibit less microphony. We've found that the Russian, military grade, tubes perform the best in our circuits.

Regarding leaving your preamp on all the time, please understand the optimum life for good tubes is 2-3000 hrs. Our stand-by circuit prevents thermal shock and, over the past 20 years, we've proven it prolongs tube life. Regards, Jerry/AI's Service Mgr.

lugnut
1,190 posts
 
The AI supplied tubes work quite well and in the long run probably save you money and certainly will save you the frustration you're experiencing now. Just spend the money. Heck, I just layed out $140 for a pair of tubes for my newest preamp and it requires a total of nine tubes. There is no free ride, and IMO as a previous AI owner, the performance to cost ratio of these preamps is quite high.
thorman
1,262 posts
 
Lugnut makes a good point. Even stock tubes from the Audio Manufacturer are usually tested and screened better.Don't forget they also want there stuff to sound there best.I have been buying stock tubes from Thor Audio for 8 years and never had a problem.Are they a little more expensive that way? Yah a bit ,but I know they have been screened and tested and with that I get great sound with long life...I would go with the Manufacturer.
kavakidd
3 posts
 
I use matched 6H23-EBs from Kevin Deal at $30.00 each (this is NOT expensive) with excellent luck. I used them in my previous 3A as well.
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