on Sluckey's documents this build requires a power TX wit 150mA HT sec wiring. is this really necessary or can I use a 600V CT with 100mA too for this build? Also, can I use 6V6GT in the power section instead of the 6973's ?
note: same for the OT, I would like to use the Hammond 1750 PA in my stash. 8400 ohm CT 18 watt
thx
You can make lots of changes, just don't expect it to be the same amp in the end.
The 100mA PT is cutting it a bit short though. Might run warm and sag more than expected.
They did make 6424s with 6V6GTs, some will argue they are not the same. Maybe... But given that the only current production 6973 is the EHX that is considered pretty bland, I can see the interest in going with the 6V6. I did build mine with 6973s, because why not. Then I converted it to a Blackface circuit (turns out I had no use for a 6424 in my gigging life) and it sounded like a Blackface amp. It has since been rebuilt for 6V6 due to availability... so I get it. I also switched to a GZ34 recto and fixed bias at the same time so can't really directly compare.
OT wise... well I used a 1750E in mine. Same impedance (or close) as the 1750PA, but it is smaller and lighter. Both will work, but the 1750PA is technically a "better" OT and might sound too good... if you will. Both are very cheap. Oh yeah, when I changed to 6V6 I also changed to a 1750PA. Man do I love this amp now, but it is faaaaar from its original 6424 days. I do miss the grid biased channel, it was fun... but useless for me live (I play out way more than I play in).