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#1 PT15 se A2 operation

Posted: Thu Mar 02, 2023 11:44 am
by ACPEN
Recently cobbled a 2E22 se A2 amp (g1+g2 driven) - excellent results. On a whim I substituted PT15's - now like many, I've used PT15's in class A with good results but not A2.
Taking care not to overrun g1, results are comparable to the 2E22. Also careful to connect g3 to filament mid point or can oscillate if connected to anode.
Anyone else tried this with PT15?

atb
David

#2 Re: PT15 se A2 operation

Posted: Thu Mar 02, 2023 4:04 pm
by Mike H
Hello David, long time no see! Image

Any chance of a schematic? Struggling to get my head around it. :D

#3 Re: PT15 se A2 operation

Posted: Thu Mar 02, 2023 4:53 pm
by ACPEN
Hello Mike
It is a long time Tonbridge I think.....Danbury was a loss, still have transformers working!
I'll do a sketch (sorry no cgi here!)
It's basically just the usual A2 format but using +ve drive to g1 + g2 strapped - works with most transmitter pentodes to varying degrees.
Nothing new or special.....
atb
David

#4 Re: PT15 se A2 operation

Posted: Fri Mar 03, 2023 9:39 am
by Paul Barker
Where did I put those PT15’s?

#5 Re: PT15 se A2 operation

Posted: Fri Mar 03, 2023 12:25 pm
by ACPEN
Sketch of cct - told you it wasn't anything special!

Valves are 6SJ7 6Y6 PT15