This PDF, from VMI, may be of interest. Among other things, it shows how to calculate regulation in a multiplier. Also, look at the full wave series circuitry. If C3 and C4 connect to AC, instead of (respectively) C1 and C2, you get a full wave series-parallel setup. That topology deals with regulation, ripple, and whatever. Most unfortunately, it's EXPENSIVE to execute. 'Lytics are fine in the central "spine", but the "arm" caps. connecting the stacked bridges to AC have to be AC rated non-polar plus high value. The motor run parts needed in a multi-stage setup will put a serious dent in your bank balance.
I saw this transformer listed on Ebay, I was immediately suspitious of it and concluded at the time it was definitly from a transistor amp, and the seller should have known it!
Personally I'd go for a full refund.
Personally I'd go for a full refund.
Yeah, After all this discussion, I've decided to ask him for a refund... Its a bit annoying, But oh well.. Thanks for all the help guys!
If you can't get a refund then you could do a 'positive' doubler and a 'negative' doubler off one end of the 70V secondary - although the regulation would not be fantastic, it would be practical for a guitar amp as the sag may be just what you need (similar to old power supplies).
Probably achieve an idle B+ of 350V, and ok for PP output and then extra filtering for screens and preamps.
The doublers would be the capacitor input - two capacitor-two diode type (as per bias configuration in http://dalmura.com.au/projects/McPherson Mk IV schem modified.pdf ) but increased capacitor levels, something like 200uF 200V electrolytics scavanged from switchmodes.
Ciao, Tim
Probably achieve an idle B+ of 350V, and ok for PP output and then extra filtering for screens and preamps.
The doublers would be the capacitor input - two capacitor-two diode type (as per bias configuration in http://dalmura.com.au/projects/McPherson Mk IV schem modified.pdf ) but increased capacitor levels, something like 200uF 200V electrolytics scavanged from switchmodes.
Ciao, Tim
First of all, read:
Marshall JMP 50 | Amps | All Amps
You need 250-0-250 V (and filament of course).
Marshall JMP 50 | Amps | All Amps
You need 250-0-250 V (and filament of course).
Hey, I managed to get a refund and the seller said I could keep the transformer.. So any ideas for this transformer to go to use in a 50w valve amp would be great!
I'll read these two documents tomorrow when I get the time... I basically just need anything at a really cheap price as I'm not too worried (at the moment) about top quality sound.. To be honest, A working Valve amp would be great! - Then I can start replacing the cheap things with better quality components..
Least that's my plan!
I'll read these two documents tomorrow when I get the time... I basically just need anything at a really cheap price as I'm not too worried (at the moment) about top quality sound.. To be honest, A working Valve amp would be great! - Then I can start replacing the cheap things with better quality components..
Least that's my plan!
and +300-0-300 if you don't want to starve the output-tubes into heavy clipping, which sometimes sounds terrific with a double-stack of 12" speakers (eight in all series/parallel so that the poor output-tranny really gets to work).
Don't worry - guitaramp-territory is quite different to hi-fi. As long af some fundamental rules are followed!
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