26-10-2016, 09:30 PM
(This post was last modified: 26-10-2016, 09:37 PM by Mike Watterson.)
Joe Sousa is a very expert Electronics Design Engineer of ICs and has a website on Philbrick history. He is vintage radio collector, vintage valve collector and experimenter.
The 6AS6 is based on curiosity rather than a pragmatic approach based on common NOS valves. You'd need a heptode or at minimum a hexode. While I correspond with Joe and think he comes up with great stuff, I'd not build that one.
So build a slightly different design based on ECH81
Search 6I1P / ECH81 / 6AJ8 tubes. Lot of 10 pc. NOS!
Very many NOS East European suppliers.
The Triode section uses identical circuit to any AM Radio. Easily adapted for crystal, but a double gang tuning cap can tune triode and other half the loop on Anode of the Hexode section, the grid of which is fed with Audio instead of RF from an aerial.
If you want 12V or 24V (better) look at 12V ECH83 car radio mixer/osc. Same valve. You do need two to run the heater off 12V. So the second one can be AF amp and RF amp, or some other 300mA 6.3V valve.
Or use 2 x EF80 or 2 x EF91 as pentode mixer and triode Osc, though you'd want a normal HT I think.
Here Joe Sousa discusses advantage of ECH81 over heptoe/octode
http://www.radiomuseum.org/forum/ech81cu...ces.html#1
The 6AS6 is based on curiosity rather than a pragmatic approach based on common NOS valves. You'd need a heptode or at minimum a hexode. While I correspond with Joe and think he comes up with great stuff, I'd not build that one.
So build a slightly different design based on ECH81
Search 6I1P / ECH81 / 6AJ8 tubes. Lot of 10 pc. NOS!
Very many NOS East European suppliers.
The Triode section uses identical circuit to any AM Radio. Easily adapted for crystal, but a double gang tuning cap can tune triode and other half the loop on Anode of the Hexode section, the grid of which is fed with Audio instead of RF from an aerial.
If you want 12V or 24V (better) look at 12V ECH83 car radio mixer/osc. Same valve. You do need two to run the heater off 12V. So the second one can be AF amp and RF amp, or some other 300mA 6.3V valve.
Or use 2 x EF80 or 2 x EF91 as pentode mixer and triode Osc, though you'd want a normal HT I think.
Here Joe Sousa discusses advantage of ECH81 over heptoe/octode
http://www.radiomuseum.org/forum/ech81cu...ces.html#1
