Phase inverter tube recommendations?

bassjoe613

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!

Music Man Equipment
MM 2-10-65

Member for

10 years 9 months
Profile picture for user mm210

mm210 Sat, 07/24/2021 - 03:58

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 That 1/2v at point y advice is a little outdated.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.

Full Name
Joe W
Music Man Equipment
1978 HD130 Bass Head

Member for

3 years 5 months

bassjoe613 Mon, 07/26/2021 - 09:51

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?

Music Man Equipment
MM 2-10-65

Member for

10 years 9 months
Profile picture for user mm210

mm210 Tue, 07/27/2021 - 16:18

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.