Okay, what did my amp do?

[Marko5657]

Line6 HD400 head, been gigging it for a few months now, no prob’s.

Last night, plugged up, tuned up (onboard tuner), but no sound from the cab.

Battery in the bass was good, signal was getting to the head, bass into guitarist’s cab worked, head into drummer’s wedge- no sound. Tried different cables & inputs to the cab (GK 212mbe) etc, no power from the head.

The direct out to the PA worked, so I just put some in the monitors and got by fine.

I left it plugged into my cab, from about 8:30PM to 1:AM. and it never came on.

I have to ASSume the power amp in the head was not working.

Head lives with everything else in the cold band trailer (and the weather got cold recently,) so I took it home, it sat in the house all night, and today, same bass, and it works fine.

Could it be because it can’t handle the cold/moisture in the trailer?

I never had or even heard of anyone having a problem with electronic gear left in the cold. Drummer did say there was lot of moisture on the kit, so maybe a combination of cold and condensation affected it.

In any case, I’m gonna be taking it home from now on so it doesn’t get the cold and condensation.

[craig.p]

I'll vote for condensation being the cause. All it might take is for the resistance between two adjacent circuit board traces to drop a bit because of water mist on the board, and then you have current leakage where there shouldn't be any. PCB technology has come a long way with respect to circuit density but the down side to density is that these circuits can be far more sensitive to "off spec" operating environments. Also there are digital signals present inside many new amps, e.g. for modeling, and so condensation might change the waveforms and/or amplitudes of those signals, maybe even cause one waveform to modulate another waveform, with the net effect that the effective timings would go out of whack. Tough to say exactly what part of the amp got temporarily knocked down, but you're definitely doing the right thing by avoiding sudden temperature swings.

[christw]

Sudden temperature changes and consequential condensation are a risk for any amp. I'd give it a cautionary warm-up period of at least an hour before useage if it's moved from outside temperature to inside temperature. If the problem persists, it's probably something else.

[Marko5657]

Thanks fellas…

Yeah craig.p, this head has FX, modeling, etc, crap I don’t use, but I did get it because it has a tuner (and a compressor is cool, I guess), since I don’t want anything on the floor.

I guess I’ll just bring it home from the gigs so that doesn’t happen again, ‘till I get another simpler head.

Again, thanks.