What would happen if one was left on standby for a long time. I was taking the cover off one of mine and just as I was lifting it off I thought “Gee…I was pretty drunk last time I used this, I hope I turned it off.” Fortunately it was turned off, but what’s going on when in the standby mode? How long is too long?
I’m an electrical incompetant so go easy on the tech speak.
P.S. I played it last weekend , so, about a week.
Would that have killed it?
Seasoned it to tone perfection?
I don’t actually know the answer (and am in fact a little vague what standby on a tube amp actually does aside from isolating the amp from the speaker), but I googled this up, which will have to serve until someone comes along who knows what they’re talking about:
Like it says in the thing Squeegee posted, you’d most likely shorten the life of your tubes. You’d probably have to have them replaced (and that’s not something you’d want to try yourself unless you really know what you’re doing).
Depends on the amp. I have a Fender Blues Jr, and changing the tubes isn’t difficult, and I’ve done it. Mechanically it’s a bit of a pain, but there’s little fear of touching hot voltage and getting fried or anything, and this has been my experience in other Fender amps. Which of course doesn’t speak to all amps, and someone changing tubes should probably know what they’re doing, since lethal failure is sometimes an option. So, yeah: be careful.
[QUOTE=River Hippie]
… what’s going on when in the standby mode? How long is too long?
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Valves/tubes need to be hot* to function. In standyby the main juice** is turned off and only the heaters are left on, keeping the valves at working temperature without running unnecessary current through them***
OK I’ve relegated some stuff to footnotes.
- specifically the cathodes, they need to be hot to squirt off (sorry, emit) electrons. Proper 1920’s style electronics here, none of that valence band crap.
** the high tension voltage circuit, you did ask for the non-technical version.
*** Quiescent current depends on the amp’s class and biasing, go see the Great ongoing guitar thread for details.
Thanks for the answers!
Didn’t occur to me at the time but I should have just posted this thread in the OGT in the first place.
Electron tubes rely on thermionic emission to function. That is, they have to have the filaments or heaters on to give up electrons. Used to be that common procedure was to leave a tube powered device instrument “on” to reduce “Current inrush” on power up. This is the same phenomenon that kills the usual incandescent bulb when you turn it on and it flashes out. Standby mode usually leaves on the power to the filament without hv to the cathode. It’s a trade off, and ymmv.
Pitter Patter;15091822]Electron tubes rely on thermionic emission to function. That is, they have to have the filaments or heaters on to give up electrons. Used to be that common procedure was to leave a tube powered device instrument “on” to reduce “Current inrush” on power up. This is the same phenomenon that kills the usual incandescent bulb when you turn it on and it flashes out. Standby mode usually leaves on the power to the filament without hv to the cathode. It’s a trade off, and ymmv.
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The primary issue with leaving an amp on standy mode a long time is the waste of energy. Tube life won’t be affected much at all if you leave an amp on standby for a whole week. During standby, the tube heaters are turned on, but the amplifer circuit is off. The purpose of standby is to allow the tube components to heat up before turning on the amp; the sudden current flow on cold tube causes thermal shock and reduced tube life. Standby also allow one to keep the tubes warm between sets or smoke breaks at the studio or whatever. Some guitarists argue that tubes sound best after being hot at least an hour or two. I think there’s some truth to that on some amps. I even met a studio sound engineer who suggest leaving tube amps on standby in the studio for a full day prior to recording.