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Regulate low voltage power supply for SS/Tube hybrid?


 :
3/12/2004 12:28 AM
jon
Regulate low voltage power supply for SS/Tube hybrid?
Before I get any deeper into my next (hybrid) pedal design, any thoughts on the necessity of using a regulated low voltage supply for a TL072 dual opamp, a few jfets, and a low voltage mosfet/LED? The high voltage tube plate supply will have pretty stiff filtering and a few nodes for around 300V DC down to below 100VDC. I'll be running a 12AX7, EF86, and 6V6 off this supply.  
 
I've built tube pedals before with transistors and LED's( input or output buffer here and there, Millenium Bypass type switching annunciation) , usually just use a big dropping resistor, zener clamp and some capacitance at the last (9-12VDC)node.  
 
Recently read a bit about using hybrid designs with op-amps for reverb circuits in some of O'Connor's TUT's, and he highly recommends active power supply regulation for the op amp....overkill?  
thanx,  
Jon
 
3/13/2004 3:11 AM
KB

I think it's a good idea jon. An LM 317 HV works real well and even a 7812 or 7815 depending on how high you want it or how much headroom. The 317 HV won't fry as easy as a stock LM317 and you could easily connect a adjustable pot and some reverse diodes for protection. The zeners are ok for a quick cheaper regulator but not as stiff as an LM317 which btw of course would have to be heat sinked as they will get a tad hot when soucing current. IMO the MOSFET would be overkill but would work extemely effective and quite effecient but a tad more expensive. The cool thing about the adjustment is you can toy with the amount of headroom on the op-amps to get exactly what you want as with a 7812 or zener your fixed so what you got is what you got. Hey, what the hell ya building ther jon btw :). If it's a secret shoot me an email. I've been venturing into the fuzz face thing a bit but time is kicking me right now.,  
 
KB
 

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