JTM45 Based Amp Build
5 May 2020.
I found an RS DeLuxe output transformer in an old DIY PA amp that was being cleared out out from a cellar at a company I used to work at. I suppose it used to power the intercom call system.
I took the excellent Mullard XF4 EL34 valves to use and put the rest of it aside for a few years. When I came to have a good look at it, on examination, the OT was a legendary RS Deluxe! After a slow power up to reform the ecaps, and with a full compliment of valves in place, it worked fine, though the HT was stupidly high, about 550V.
So I took the OT out and planned a JTM45 based build around it.
OK, it has the patina of age but that's just part of the magic.
Chassis interior.
I found an RS DeLuxe output transformer in an old DIY PA amp that was being cleared out out from a cellar at a company I used to work at. I suppose it used to power the intercom call system.
I took the excellent Mullard XF4 EL34 valves to use and put the rest of it aside for a few years. When I came to have a good look at it, on examination, the OT was a legendary RS Deluxe! After a slow power up to reform the ecaps, and with a full compliment of valves in place, it worked fine, though the HT was stupidly high, about 550V.
So I took the OT out and planned a JTM45 based build around it.
OK, it has the patina of age but that's just part of the magic.
Chassis exterior, transformers and sockets mounted, with unpopulated circuit board.
Chassis interior.
I orientated the sockets to facilitate a 'modified Valve Wizard' method that occured to me; it seemed a good idea to use the space between terminals 1&9 to allow easy access for the heater wire.
The arrangement recommended by Valve Wizard (ie the one on the right) seems a bit more fiddly to me.
The arrangement recommended by Valve Wizard (ie the one on the right) seems a bit more fiddly to me.
Busy assembling the circuit board now.
7th May 2020
Power supply wiring and circuit board pretty much done!
7th May 2020
Power supply wiring and circuit board pretty much done!
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