Telecaster Guitar Forum - View Single Post - Firefly

JamesS2 · July 21st, 2012, 12:22 PM

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?

July 21st, 2012, 12:22 PM	#5 (permalink)
JamesS2 TDPRI Member Join Date: Jan 2012 Location: Uk, South Yorkshire Posts: 16	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?