2. amps-preamps
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Joule electra Pre Amp -tube rolling

time to roll some tubes on my la 100 mk2. Quick review of some of the forums seems to convey that the joule is less sensitive to tube rolling and thus NOS may not be cost effective. Any thoughts from prior owners/experimenters would be appreciated. May be just a case to simply call joule an order up what ever they use. The line up i believe is:

1 - 5751
1 - 6350
2 - OA2
2 - 6EM7

Thanks all
kbuzz
clio09
3,360 posts
 
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.
spectron
130 posts
 
Hello guys,

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

Thanks in advance
Simon
clio09
3,360 posts
 
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.
pubul57
3,712 posts
 
Tony, I think they are GEs, at least they were in my unit.
clio09
3,360 posts
 
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.
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