# Tube guitar amps on "standby".... **URL:** \ **Category:** Cafe Society\ **Created:** [May 21, 2012, 12:00am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561 "2012-05-21T00:00:42Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![River\_Hippie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/river_hippie/32/26_2.png) [@River\_Hippie](https://boards.straightdope.com/u/River_Hippie)\ **Post date:** [May 21, 2012, 12:00am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/1 "2012-05-21T00:00:42Z")
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.😛 ---
**Author:** ![River\_Hippie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/river_hippie/32/26_2.png) [@River\_Hippie](https://boards.straightdope.com/u/River_Hippie)\ **Post date:** [May 21, 2012, 1:31am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/2 "2012-05-21T01:31:07Z")
P.S. I played it last weekend , so, about a week. Would that have killed it? Seasoned it to tone perfection? ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [May 21, 2012, 3:59am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/3 "2012-05-21T03:59:29Z")
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](http://www.thegearpage.net/board/archive/index.php/t-132505.html) up, which will have to serve until someone comes along who knows what they’re talking about: > [@Some guy on the Gear Page](#): > > It doesn’t cause wear, but it does something else nasty called ‘cathode poisoning’ (or ‘sleepy tube sickness’). This is a change in the chemical properties of the cathode coating caused by being run hot but with no current flowing, and eventually leads to it becoming less effective. It’s very slow, and I certainly wouldn’t worry about it over an hour or two… but maybe overnight. > > What I’ve never been able to find out is whether the effect is reversed when the tube is put back to normal operation - in other words, does it recover if you then leave the amp fully on (even if it takes the same sort of time period). > > The real difficulty is to decide when to turn off and when to put on standby if you’re not going to use the amp for a while… there are three factors: if you turn it off, you cause extra heating/cooling cycles (which are definitely bad for tubes and possibly other components); if you leave it running (especially at the sort of high idle currents that many guitar amps have) you are continuously wearing the tubes; and if you put it on standby you’re risking cathode poisoning. There’s no straightforward answer… ---
**Author:** ![Kim\_o\_the\_Concrete\_Jungle](https://avatars.discourse-cdn.com/v4/letter/k/ee7513/32.png) [@Kim\_o\_the\_Concrete\_Jungle](https://boards.straightdope.com/u/Kim_o_the_Concrete_Jungle)\ **Post date:** [May 21, 2012, 5:07am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/4 "2012-05-21T05:07:39Z")
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). ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [May 21, 2012, 5:40am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/5 "2012-05-21T05:40:40Z")
> [@Kim\_o\_the\_Concrete\_Jungle](#): > > 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. ---
**Author:** ![Small\_Clanger](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@Small\_Clanger](https://boards.straightdope.com/u/Small_Clanger)\ **Post date:** [May 21, 2012, 9:57am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/6 "2012-05-21T09:57:19Z")
[QUOTE=River Hippie] … what’s going on when in the standby mode? How long is too long? [/quote] 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\*\*\* > [@](#): > > I’m an electrical incompetant so go easy on the tech speak. 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. ---
**Author:** ![River\_Hippie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/river_hippie/32/26_2.png) [@River\_Hippie](https://boards.straightdope.com/u/River_Hippie)\ **Post date:** [May 21, 2012, 10:01pm UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/7 "2012-05-21T22:01:33Z")
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. ---
**Author:** ![Pitter\_Patter](https://avatars.discourse-cdn.com/v4/letter/p/90db22/32.png) [@Pitter\_Patter](https://boards.straightdope.com/u/Pitter_Patter)\ **Post date:** [May 23, 2012, 4:43am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/8 "2012-05-23T04:43:06Z")
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. ---
**Author:** ![Pitter\_Patter](https://avatars.discourse-cdn.com/v4/letter/p/90db22/32.png) [@Pitter\_Patter](https://boards.straightdope.com/u/Pitter_Patter)\ **Post date:** [May 23, 2012, 4:44am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/9 "2012-05-23T04:44:48Z")
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. [/QUOTE] ---
**Author:** ![Enlightening\_Meditation](https://avatars.discourse-cdn.com/v4/letter/e/ecc23a/32.png) [@Enlightening\_Meditation](https://boards.straightdope.com/u/Enlightening_Meditation)\ **Post date:** [May 26, 2012, 4:46am UTC](https://boards.straightdope.com/t/tube-guitar-amps-on-standby/622561/10 "2012-05-26T04:46:24Z")
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.