Getting into Amp building/modding

JiM · Post by **JiM** » 02 Sep 2008, 19:43

For the second option, you can also tape the resistor to a wooden ice-cream stick, and discharge the caps one after the other by touching their connections with the leads of the resistor. The wooden stick is IMHO a lot safer than crocodile clips unless they are completely surrounded by rubber insulation.

The main rule while wotking with high-voltage (and it's worth over-repeating) : only one hand in the amp at any time ! Just stick the other one in the back pocket of your jeans. There's almost nothing as deadly as a high-voltage discharge from hand-to-hand, through the heart.

Obviously, the bigger the resistor value, the longer you'll have to wait for the cap to discharge.

Post by **modman** » 03 Sep 2008, 08:49

The guy I bought my first amp from, discharged the caps this way: unplug power cord while strumming your guitar until the sound dissapears. Is this a valid method?

marshmellow · Post by **marshmellow** » 03 Sep 2008, 09:34

I've heard/read that several times. I wouldn't trust it without measuring afterwards...

TragicTravisty · Post by **TragicTravisty** » 03 Sep 2008, 19:47

i also heard once to plug it in, with the power off but standby on. also, couldnt i just leave it unplugged overnight

?

petemoore · Post by **petemoore** » 08 Sep 2008, 15:56

The pro's sometimes solidly recommend trusting the DMM leads.
I thought a good way to do it would be to have an LED indicator which doubles the DMM leads reliability and lights whenever HV is present...Don't mention it to a pro...they'll cut your head off for just thinking maybe there could be a better way.
Fine is good...as long as you test that the wires I vote as most likely to fail haven't failed.
I have this routine, unplug my amp, measure that the voltage indeed dropped quickly like it always has, put that bleed resistor on there anyway.