• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Frank's 6sn7 preamp


2008-12-28 4:48 pm
I’m looking for a tube rectified power supply for Frank,s 6sn7 preamp. I have done a search and have come up empty. Parts I have, Hammond 270BX(550V-50mA), 5u4gb rectifier. I would like to try designing one myself but don’t know where to begin.

Any help on a power supply for this preamp would be appreciated. Mean while I'll keep searching.


2006-11-26 9:08 pm
Ok, I believe it's enough.What I've done is a simple CRC (220 uf-50 ohm-220 uf) and after that Salas HV shunt regulator @ 30-40 mA with amazing results.You must have at least 265 V before the regulator to regulate @250V.
Which version of the preamp are you building,the direct coupled or the cap coupled?
I prefer the direct coupled one.
Here's what I'm using:
Only because it's a PT that I had on hand scavenged from an old HAM radio. Some of the cap and resistor values may have changed slightly, but it's basically the same circuit. I think I have a 100uF as the last cap now. I was trying to tune the output voltage to the 250V using the resistors. Probably a waste of power for the tranny as it was made to supply more tubes than I am now using, but again I already had it.
Mine's dead quiet with this power supply.