Luigi customs pcb conversion

[mattjaco1]

Hello,
I recently finished a hot rod deluxe to Luigi customs pcb conversion. It fired right up no issues sounding great. My son played it out for the first time tonight on a 4+ hour Beale street gig here at BB Kings in memphis.
It sounded great, Lots of compliments. However, 15 min into his last set, it started crackling. He shut the amp off for a few min and fired it back up working fine. The band after them played and their guitarist used the amp for another 4 hour set and it worked fiine for him. New power tubes, v2 and v3 are new, v1 was an older Ei 12x7. Any ideas? What could I check?

[mattjaco1]

Anyone?

[xtian]

Standby switch is always a concern. Other than that, bad solder connection, ground connection, etc etc. Try chopsticking everything.

[GAStan]

How much time did the amp have powered up prior to the gig? Is it possible the tubes are still burning in?

[timrobertson100]

Are you sure it was the amp?

[mattjaco1]

Amp had been on maybe 4 or 5 hours after being built. I will have the amp home tonight. We just tried to use it here now and same thing crackle sound in both channels.. we unplugged effects loop and pedal board, different guitar cables. Same issue. It did sound amazing though when working. He was pushing it pretty hard master was around 2 o'clock. I will try a different speaker when I get home as well.

[erwin_ve]

Amp had been on maybe 4 or 5 hours after being built. I will have the amp home tonight. We just tried to use it here now and same thing crackle sound in both channels.. we unplugged effects loop and pedal board, different guitar cables. Same issue. It did sound amazing though when working. He was pushing it pretty hard master was around 2 o'clock. I will try a different speaker when I get home as well.

The hardest thing when troubleshooting is when the trouble is not consistent when you're looking for it.
I'll add my 2 cents: check the bias current /voltage on the powertubes. If one of them powertubes is trouble, you should see large fluctuations in the bias current.

Erwin

[mattjaco1]

Found issue. Blown grid resistor on v5 power tube.