Warning!
Not all Billm mods are created equal! Some amps advertised on eBay as new, with Billm mods, are neither built by me nor use my kits or parts that I specify. I have had the occasion to examine a couple of these amps, and I believe that some of the components used and workmanship do not meet my standards, nor industry/safety standards. I’m not about to teach an imitator how to do a better job, so I won’t go into detail here, but as a potential purchaser, you should make an informed decision. Also, some clone kits use incorrect parts that do not fit well or may cause hum.
Update:
Now I see the main offender claiming on eBay that Blues Juniors are cathode biased and that adjustable bias is DEAD WRONG (his emphasis). Um, Blues Juniors are not cathode biased. Then he includes a quote from Randall Smith (Mesa Boogie) that mentions bias but is otherwise completely irrelevant. I see that I’ve embarrassed the guy into providing isolation washers, but he still isn’t using shielded wire on the input jack.