Recommendation for preamp tube for AD140TC?

[bclaire]

One of my preamp tubes went extremely microphonic last week. Shrill, say we say? Anyway, I replaced the first two preamp tubes with Mesa SPAx7's for the low noise, etc., and for the simple fact taht those were all I could quickly find around here. Anyone else have any preferences or suggestions? These seem to work fine but how do they compare to the Ruby tubes that came with it? (as if I don't already know.....) Thanks Billy

[messner]

In my AD140TC, I put Electroharmonix 12ax7's in the pre-section and Svetlanas in the post. Wow! All I can say is that I like the amp 100% more than I did before. I can't say it's better for you because tone is subjective, but for me, it's a ton better. Picking individual notes in an already ringing bar chord are far more defined whereas before, It would not define individual notes picked in a ringing chord at full distortion. Harmonics became much more predictable. I would definately suggest this tube combination for anyone who is not satisfied with their tone. Finally, they gave it balls.

[VintageJon]

bclaire: As a Ruby dealer for years with MANY happy customers I
will try to answer your question. Ruby sells 3 grades of preamps tubes- High Grade,Select, Untested. High Grade is selected for gain,
tone and low microphonics. They are garrenteed for 90 days.
Select tubes are ones with not quiet the gain of the High Grade and
are slightly more susceptible to microphonics than the High Grade.
Untested are what the name implies- you test them yourself and assume all responsibility.
High Grade and Select tubes are warrantied for 6 months against malfunctions involving defects in materials or workmanship. Microphonics within 6 months? NO PROBLEM! I replace them and the good people at Ruby send me another to replace it.
I susgesst the 12AX7CZ High Grade- $22.50 or select $17.50. For a slightly brighter sound I would go with the 12AX7A4C High grade- when available, or Select.

For a somewhat "darker" tone I would highly recommend the JJ ECC83S.
An excellent tube that Tesla/JJ has "reissued". It is a remake of the Spiral Filament Telefunken of Hi Fi fame from the 50's. They made the original for Telefunken and have an excellent "reissue". I sell them for $15.00.

MESSNER: glad you found your tone! However EH tubes are simply
rebranded Sovteks and I can not honestly recommend these marginal
POS Sovteks to anyone. The noise,weakess,microphonic,failure for
shorts/leaks rate is just too high. Then there's the lack of "tone"-
but that's a subjective matter.

-Jon Bessent
Tonecraft Amp Repair
Austin Tx

[messner]

Hey Vintage Jon, thanks for the tips. I am always looking for new sounds, and by no means have I completely found my tone. It's just a lot better than before. I would like to try some of your suggestions. Would it be possible to mail order some from you. You can contact me via email.

[bclaire]

Thanks Jon for the info. Do you know who makes the Mesa tubes? I know the SPAX7's are chosen for low noise etc but is there a specific manufacturer? Thanks Billy

[masongary44]

I recently bought/traded for an Orange AD15, It has been re-fitted with matched Mullard tubes, they really are superb, if a little hard to get hold of nowadays .

I have read some reviews and these tubes always seem to be used as a benchmark, but very little is said about the mullards themselves.

Does anyone know how they compare to others out there on the market, for example the Phillips, Sovtec and others?

Are there some alternatives that will give me more gain or is this limited more by the amp circuitry than the valves??

[Davis]

Tubes, tubes, tubes....a very interesting topic. The most interesting conversation I ever had with a "knowledgeable" person about tubes was the tech support person at Mesa?Boogie. Those guys know their stuff!!
I must have spent an hour learning about tubes. Give 'em a call on their 1-800 number. You'll be pleasantly suprised as well as educated about what tubes can mean to your sound.

Davis