[mrdon]

The DIY Morgan Jones on digi01's pcb has gone off the deep end! Everything worked fine for about a month and then the left channel tube (V2L) started to occassionally spark and pop, but the amp still seem to work fine except for a slight channel imbalance in the left channel. As time went on the sparking and popping increased. Today, I put brand new JJ 6922 tubes in the amp and the sparking and popping moved to the right channel (V2R). After a couple restarts, the sparking and popping spread to the R4R resistor and there was lights and smoke! I immediately shut it down. Upon restart, the right tube did light up but there was no sound out of the right channel only the left. To check to see if the right tube was now ruined I moved it to the left channel and it sparked and popped again and then lights and smokes came from the R4L resistor . Upon inspection, the plastic coating on both resistors has come off and there appears to be smoky residue on the pcb.

Here are some of my troubleshooting ideas:
1. Could it be that the Holco 121k resitors in R4L/R were bad and needed replacing?
2. Could be a problem with the heater wires being grounded to star ground?

Other ideas?