I just got a Tweed Pro Junior and want to upgrade the Sovtek EL84's. I've heard that PJ's can be pretty hard on power tubes. What are the best new and/or NOS power tubes for this amp. What should I stay away from because they overheat? Thanks.
I've had a PJ now for about 2 years. It is hard on the power tubes. JJ's last a long time, but I don't care for the tone personally (a bit bright and harsh). I tried expensive NOS Teslas, sounded wonderful, but were done-for after just a few months of use (severe microphonics and filament rattle), ended up with a set of Mesa Boogie Labeled tubes. They 'darken' the tone just a bit (which I like) and so far after about 6 months, still going strong and sounding good. I use my PJ as a practice amp, for very small venue gigs, and at jams where I crank it to compete with 60 watt amps (it does very well, BTW)
Thanks for the advice. I agree with you about the JJ's. I had them in a SFDR and then put in some old RCAs and the tone immediately got mellower, thicker, more to my taste too. I'll check out the Mesa Boogie tubes and EI's if I can ever find them up here.
The biggest difference in longevity will be due to the conductivity (idle current) of the particular tubes you get. It doesn't likely have anything to do with brand. Read this. http://www.kcanostubes.com/categories/32/1/6BQ5-EL84-7189A.htm You could also have a bias pot installed which would eliminate the problem for any pair of tubes you buy.
Thanks for the info Mike. Can a tech test tubes by themselves on a "tester", or do they have to be installed to see how hot their running?
Suppliers can sell you "low current" tubes, but the only way to find out how they're running in your amp is taking measurements on the tubes IN THE AMP.
One more thing. What brand of new power tubes would you recommend for a deeper, warmer sound. I find JJ 6V6's, for example, to be too hard, bright.
