Blew my amp and Noise Reducer! :-(

I blew my Marshall 100DFX and ISP Decimator last night, terrible timing seeing as I have a session this weekend (luckily I have a Mesa rig for primary parts). Anyway, just wondering why it happened...

I was running a line from the speaker connection on the amp through my Palmer PDI-03 (speaker simulator) then into my soundcard. While doing this, I unplugged the guitar, and touched the unconnected jack against the Decimator. The amp blew immediately (power died instantly), when I came back 5 mins later, the Decimator was dead...

Could a charge have transfered from the Amp to the Decimator or vice versa across the guitar line? I didnt think that was possible... I don't want to make the same mistake twice, if anyone knows why this might have happened let me know. Thanks..

Checl your AC power wiring. That sounds like there's an open ground line and/or the phase & neutral wires have been transposed somewhere.

Be careful. If one of your equipment chassis has gotten hooked up to the hot side of the AC line, you could get electrocuted! :eek:

You sound like you know what your talking about... unfortunately I know very little about electrics etc.
I'm running my rig in a rack setup. There is some US and UK gear in there so there are different power supplies (using power convertors). I'm running the Triaxis through its own independent plug an power adaptor as it is grounded and requires some serious power. However, everything else is running off an extension plug board (can handle six plugs).
How would I find out about an open ground line? How about the transposed phase? Sorry for the basic questions, just never had to tinker with wiring before.

Every player should have a line-checker in their kit. It's an AC plug that has three lights in it. You plug it into an outlet and some of the lights will be lit. You compare compare that pattern with a chart on the plug to see if the outlet is wired correctly or not. This lil' darlin' can save your life. I urge everyone to get one of these things and to use it before you plug in to an AC plug anywhere, even at home.

Most hardware stores will have them. Electrical supply shops certainly will. A few bucks is a small price to pay for the safety of you and your bandmates.

Nice one, thanks for the info. I'll get one this weekend.

Originally Posted by: LordathestringsChecl your AC power wiring. That sounds like there's an open ground line and/or the phase & neutral wires have been transposed somewhere.

Be careful. If one of your equipment chassis has gotten hooked up to the hot side of the AC line, you could get electrocuted! :eek:

to me, it sounds like he could have shorted out both his amp and noise supressor by connecting the hot of the plug to the ground of the pedal (since pedals and some amps are normally grounded to their chasis).


just another thought to be thrown out.

did he even check the plug on the outlet to see if anything else worked?

All of the other gear on the plug board works fine and the amp and noise reducer still don't work if I plug them into different independent sockets... The only thing that connectec the two devices at the time they blew was a audio cable (1/4 inch jack). Anyway, I'll be getting an AC checker now so hopefully it won't happen again.