Amp left on for a week..........what damage ?

Dominic

Mistakenly left a good quality amp on whilst away for a week ....still on when I got back
plugged in and its going ' chrrrrrrr,ghrrrr,zhaaaa '
What have I done ?.........is it likely to be just a pre-amp valve ?

ICBM

Properly designed amp: no problem.

What amp is it?

ecc83

I agree with IC, no half decent design would be fazed in the slightest. Fork! Many 'stooodio' nutters leave their rigs powered up forever!

I consider that totally stupid, no technical reason for it and it is very bad for the planet.

BillDL

Dominic said:

plugged in and its going ' chrrrrrrr,ghrrrr,zhaaaa '

Does it have an integrated spring reverb?

richardhomer

Dominic said:

What have I done ?

Probably spent the equivalent of a Dumble on electricity…

bertie

richardhomer said:

Dominic said:

What have I done ?

Probably spent the equivalent of a Dumble on electricity…

and kept the whole house warm

Dominic

ICBM said:

Properly designed amp: no problem.

What amp is it?

One of those cheap CARR amps !!!!!

UnclePsychosis

Dominic said:

What have I done ?...

To add insult to injury you could've probably bought a new amp with the additional electricity costs... 

Dominic

does it really cost much to have an unused valve amp switched on ?

Devil#20

Dominic said:

does it really cost much to have an unused valve amp switched on ?

You're still heating the valves even on standby. In fact that's what the standby does so you don't have to re-warm them up if you take a break from playing. 

ICBM

Dominic said:

One of those cheap CARR amps !!!!!

Doesn't mean it's properly designed - I can think of at least one other expensive amp brand which I wouldn't want to leave on for that long, and which I also wouldn't say was properly designed. I'm not familiar with Carr, but a lot of amps run the power valves so hot that a week (168 hours) might be a significant fraction of the valve life expectancy. Temperature rise inside the chassis could be an issue too, I had a Mesa Trem-o-verb which got to 85ºC inside after a few hours, with no sign of it stopping rising. (I was monitoring it with a thermocouple probe poked through one of the jack holes, because I was concerned how hot it got.) That's about the temperature at which some components, especially electrolytic caps, start to have very shortened life expectancy.

I once left a 60s Vox AC4 on for several days too - they don't have a pilot lamp as stock - and it was perfectly fine afterwards.

UnclePsychosis

Dominic said:

does it really cost much to have an unused valve amp switched on ?

I think a 100W amp will draw "something like" 30W when idling and 150W at full pelt. 

Its not a huge amount, but at the current price of fish... 

ICBM

UnclePsychosis said:

I think a 100W amp will draw "something like" 30W when idling and 150W at full pelt. 

Its not a huge amount, but at the current price of fish... 

More than that. A cranked 100W amp can draw up to about 400W - old Marshalls are labelled 375W.

At idle, just over 100W - the power valve idle dissipation alone will be around 60W (4x 15W), plus a few watts for the B+ chain, plus the valve heaters.

On standby, about 50W - four EL34 heaters at 1.5A plus three 12AX7s at 300mA, at 6.3V is 44W, plus a small amount of loss in the PT, and the pilot lamp!

Something like a Fender Twin has a few more preamp valves but the 6L6 heaters draw less than EL34s, so it will work out about the same.

BillDL

I once cooked a whole chicken in 6 hours with nothing but a 100W tungsten bulb.

ecc83

UnclePsychosis said:

Dominic said:

does it really cost much to have an unused valve amp switched on ?

I think a 100W amp will draw "something like" 30W when idling and 150W at full pelt. 

Its not a huge amount, but at the current price of fish... 

Bit more than that chuck. Heaters draw 37W (EL34s) and a 'coolish' 25mA bias and 450Va gives a total of 85-90W

Dave.

Dominic

BillDL said:

I once cooked a whole chicken in 6 hours with nothing but a 100W tungsten bulb.

Bill Grylls ......or should that be Grills

prowla

Hi-Fi amps are designed to be left on permanently.

bertie

prowla said:

Hi-Fi amps are designed to be left on permanently.

they'll be banned soon then

TheMarlin

I leave my Hifi power amps (monoblock) permanently plugged in and turned on.  They’ve not been off for at least three months. 

It’s the powering on and off that kills components (especially valves), 

ecc83

prowla said:

Hi-Fi amps are designed to be left on permanently.

Not so. They may be  sufficiently well designed and made that they will survive for years but there is no evidence that I know of that there is any benefit to 'cooking' them.

If a transistor amplifier does not reach stable operation and specified distortion within ten seconds of power up it is a bad design.

Valve amps produce SO much more distortion than even mid market transistor hi fi that their thermal gymnastics hardly matters.

"On and off" buggers valves? Radios regularly lasted over a decade before needing attention and were switched off every night. Then it was usually the caps that blew. You could NOT kill those old 6V6s!

Every WMC had a 50W PA amp in a cupboard for the Saturday night bingo and other functions. Those KT66s gave 20 years of faithful service. How 'king long do you WANT the valves to last?

Some here are not old enough to KNOW how long valves last!

Dave.

Wazmeister

It’s a Carr.

End of. Rock solid.