Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp

I took this from the speaker out of the Mofo attached to the Scourge units in question. It's definitely HF garble wrapped in a 120Hz sleeve at about 1v peak to peak..
Noise gets noticeably worse when the DAC (Schiit entry level unit) is attached even if it's not powered up. However, the noise is present with no input attachments as well with inputs grounded (inputs ground by the pot being turned down). I also attached a small set of amplified speakers and heard the same buzz to rule out the Mofos which appear to function just fine with other input sources. The area isn't inherently noisy as far as I'm aware. Multiple preamp (ACP+, BOZ, etc) all function perfectly in the same spot.

Still feeling I should build up a more traditional setup (supply/regulator/grounded aluminu. Chassis, etc) Would be a bummer if that route got The same results.

The mystery continues


  • 20230315_200141.jpg
    222.2 KB · Views: 24
Last edited:
Ground strap between Mofo and scourge boards....silence!
Even with laptop supply instead of batteries.
I ended up jumpering D-- to V- and seemingly problem solved. Mofo and front end then reference ground through RCA connection.
Grrr....! Now time to put things back together that didn't need to be tore apart in the process.I

Thank You for the look ThompsonTech.
Well, I have all the resisters installed on the Dread... I can't say I ever soldered in 100 of them on an FE before. lol. I also have the few diodes in too. In past years I would have it all done by now, but not so much these days. All the Rs were there plus a couple 3.3R resistors...? Anyway, on to the rest. :)