Ray from Houston Texas sent his Holland “L’il Jimi” in for repairs.
Holland was one of the earlier “boutique” hand-made amps that appeared in the 1990’s, they went out of business eventually, but, the amp is basically a high quality great sounding amp.
It was squeeling, and, some of the pots (potentiometers) weren’t working correctly.
As it turned-out, the amplifier chassis is aluminum. Aluminum is a great conductor, except, it oxidizes when exposed to air. And the oxidized layers do not conduct electricity. The builder of the amp had relied on the pots making good electrical contact with the chassis to establish the ground reference for the pots. After many (15-20) years, the pots no longer had a good (if any) ground connection. After repairs: Now, the chassis has been buffed to remove the oxidation (in a few key places) and non-ozidizing compound has been applied (to prevent oxides from forming) and the amp sounds great. Top it off with some NOS 6L6GC output tubes and a re-bias and this baby will soon be on its way back to Texas!