|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
24.17.48.137
In Reply to: RE: Amp using PP JJ 2A3-40 posted by sony6060 on December 11, 2014 at 07:41:36
If the 2A3-40 is truly a 2.5V 300B, you could get 18 Watts out as a single ended amp... (450V, 80mA, 2K load)
You'll run the 40 Watt tube at 36 Watts, but you'll only need to buy one pair of tubes. The real trick will be finding a 2K single ended output transformer that's decent. Magnequest may be able to make a DS-020 for you.
325V/70mA seems barely worth it, unless that fits an output transformer you already have.
Follow Ups:
"If the 2A3-40 is truly a 2.5V 300B, you could get 18 Watts out as a single ended amp... (450V, 80mA, 2K load)"
Using the same Western Electric chart you refer to above, I notice that at normal operating conditions for a 2A3, e.g. Ep = 250V and Eg = -45V that the 300B will pass 80mA of plate current while we expect 60mA from a 2A3. This leads me to believe that the JJ 2A3-40 is a 2A3 with a big-ass plate; not a 300B.
Since JJ makes a 300B as well as a 2A3-40, why not just use the JJ 300B if more power is needed?
I prefer the 2.5 filament and the 2A3 grid structure.
Well, the JJ 2A3-40 is a great tube and I like the possibility to run the tubes a little hotter than the traditional 2A3 without worrying about burning them up.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: