It can also be partially fixed on Mark 1 by fitting a resistor across the line outputs

These resistors will indeed soften the pop significantly (at least on my system). To totally avoid the thump, you'll have to ask bigjohn for a schematic that keeps empeg powered until the amp has been fully switched off in much the same way as Mark-2 will do it.

Henno
# 00120 (6GB+18)