Originally Posted by JamesS2
Okay, thanks, i'll go for the 269 style tranny, seems most sensible for a 'noob'... but i'm still unsure about whether i'll need to change the power supply. How do you work out the voltage coming from a transformer? In this case is it 190V x 1.4? 266V, which fits in with the voltages given on the schematic, but then what about the change from the diodes? Does this figure need multiplying by 1.2? to give 319v? I'm guessing from the layouts i've seen I won't need to change anything if I use this tranny, but the voltages don't make sense to me, maybe they never will
When looking at specs for an OT, is the 'Max DC Bias' the same entity as the max current for the power transformer? i.e could I get away with using a 125B (with Max DC Bias of 45mA)?
Thanks for your help P, it's much appreciated, and i'll remember that bias switch. Is that the only change that i'll need to make if I swap output valve?
Depends on your load line: tubes,PSU,OT, maybe this link will help http://www.ax84.com/drums/bbs/dm.php?thread=141902
As far as the OT, basically the bigger it is, the more bass to be had. I would go with a 125C which max's at 8 watts, and better bass than the 125a or b
As I stated before, you can get a lot of help at AX84. The Firefly's designer Doug H is a regular there. You can scan through old and current post and find out about as much as you probably want to know about that amp.