Has anyone done a Hoffman board for a Dumble 124 or HRM?

[Mike_J]

Having built both of the subject amplifiers I think it would be a good project to create a Hoffman style board for a 124. My 124 gets a noticeable hum at high volumes even though I followed the exact same layout and wire routing Dumble used. Pretty sure it could be made better. Seem to recall he made a circuit that doubles the voltage just to provide voltage to his switches. Hoffman system is much smaller and more efficient to do the same thing. A lot of space is also used up in his FET circuitry for acoustic electrification that has long since seen its day. That doesn't need to be in an amp. An old Fender hi-lo system would be more useful in my opinion. Otherwise I liked the amp from a tone perspective and a friend who is a touring musician thought it was a great amp except for the hum at high volumes.


I will lay it out when I get to that amp if nobody has already done it.



Thanks
Mike