Every now and then an amp build squeals. Craig’s SL-18 was one such amp and after checking his photos it was clear why: what amp builders call ‘lead dress.’ In several areas, the wires were unnecessarily long, and allowed the preamp to pick up the signal from a later part of the power amp circuit.
“Thanks for the great information as usual. Unfortunately I got buried in work for a month – you know what that’s like – but eventually I managed to take your advice and shorten the unnecessarily long wires and can tell you that it has improved things hugely. I can run everything flat out now when I’m playing something that needs it – brilliant!”
Very kindly, Craig suggested that I post the photo to show future SL-18 amp builders how not to do it.