Joule electra Pre Amp -tube rolling

Just get the tubes from Joule. Jud Barber has an inventory of NOS tubes that he likes to use in the LA-100 preamps. Usually it is either an RCA or Ge for the 5751, Sylvania for the 6350, and Raytheon for the 6EM7 (although this one varies a lot). I can't recall what he likes for the OA2.

If you have a Joule manual Jud talks about his tube selections for the signal path. Also, when you swap the signal tubes the bias also needs to be recalibrated. Not necessarily an easy task. You may want to ask Jud about this as well.

Hello guys,

What tubes do you recommend for his LA-150 MkII preamp?

Thanks in advance
Simon

IIRC, for the linestage Jud uses the Sylvania 6350's. Same as he does for the LA-100 preamps that have this tube in the circuit. From what I've heard he has a pretty good stash of these tubes.

Tony, I think they are GEs, at least they were in my unit.

Paul,

Since you had this unit of late I would suspect Jud is out of the Sylvanias. In either case I'd go with what Jud uses.

I'm not sure, the Mk II may be slightly different, but this is what I use in the Mk III.

For the 5751, I recommend a NOS Sylvania black plate, triple mica, "D" getter with yellow lettering, not the ones with the green lettering. That tube made a vast improvement.

For the 6350, an NOS RCA black plate.

For the OA2's, I use the NOS OA2WA version made by CBS-Hytron. Not easy to find and honestly I didn't hear a difference, but the WA type is more rugged and I'm sure any WA type will be fine.

For the 6EM7's, mine actually uses 13EM7's, which Jud said he uses from time to time. I use NOS RCA's there.

Enjoy, Joule makes an excellent pre amp.

While it doesn't hurt to know what tubes a manufacturer chooses or what is recommended in equipment, ultimately, the user is trying to achieve a certain sound. So, saying which tube might sound better with which numbered tube is worthless unless at least some actual listening and comparing is done and then at least a hint is given as to the perceived tonal differences between the two or more being discussed. "So and so likes this" one and "I like this one" doesn't mean a single thing without an explanation as to why one is preferred and what it seems to sound like and ideally a reference given to another tube and the differences.

And those preference are also affected by the amp and speaker being driven. I agree with Clio9, I would stick with Jud's choices.

I'd still try an "inexpensive" set of Amperex 12AX7's to hear if you like the difference. In the Joule amps replacing the stock 5751's with Amperex 12AX7's gives a fuller sound albeit a tad less detailed. Jud bought what could get a big enough stock of which we don't have to do. We can hunt for small numbers of the tubes we like( it is getting tougher but not impossible). I think it's good to try rolling for yourself. I had a Calypso pre amp that most liked the Mullard CV-4004 '81 or one of the M-10's gold or steel pin. I used the CV-4004 until I tried an Amperex Holland 12AX7 and found it was a fuller sound that worked better for me, anyway you get the idea.