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bassjoe613

Phase inverter tube recommendations?

Hi all, so I have an 2100-130 head that has the lovely phase inverter tube. I recently took it to a tech to get recapped and retubed with JJ El34’s. I also got a JJ ecc83s for the pi slot. I’ve been reading and seeing how lots of people prefer nos tubes, long plate vs short plate, and even different types (12ax7, 12au7, 12at7).

My question is what do you all recommend for a good phase inverter tube in this amp? I mainly use it for bass and I mostly play funk, and it sounds pretty good right now, but I also don’t want the dreaded transformer meltdown from using a tube that may not be a good fit. Thanks in advance!

mm210
mm210's picture

Personally. I use the JJ for

Personally. I use the JJ for a driver tube but also, bias the amp a bit on the cooler side. That 1/2v at point y advice is a little outdated. Bias the amp, in my opinion only, 22 mA at the HOTTEST TUBE and you should be fine. Even a dab cooler won't hurt. Mike.

bassjoe613

Thanks for your reply, I feel

Thanks for your reply, I feel better now! A follow up question, how often do you think I’ll need to change the power tubes (JJ EL-34) Also, should I replace the PI tube with the power tubes?

mm210
mm210's picture

I personally think the PI

I personally think the PI lasts a long time but ANYTHING can take a dump. Changing tubes? If run cool, they can last for years, UNLESS you get a bad one. there are so many variable that they are hard to count. I don't play out anymore but my JJ power tubes have been in my 65 for several years. these days though, tubes are so all over the map in quality that you just have to take your chances. it's tough to say but most tubes today are crap. Mike.

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