Today I was practicing alone before band practice and I had about an hour between the two sessions. I shut down the rig and began to think; What is the consensus regarding standby mode vs just shutting the amplifier down and turning back on again an hour later, 2, 3? In fact what is the most amount of time you would leave a tube amplifier on standby vs just shutting down? I know, at least I think I know, that standby just reduces voltage going through the tubes thus improving life of the tubes.. but what does turning the amp on do to tube life; Anything ? Thanks for thoughts.
Quick question on tube amps
- Thread starter alund
- Start date
glpg80
Well-known member
Datasheets back in the day said not to leave the heaters on and plate voltage removed (standby for guitar amps) longer than 10 minutes, max.
The surge turning on and off your amp is harder on tubes than going to standby though. If I’m going to be away longer than 15 minutes, I turn my stuff off. Other than that, I hit standby.
Standby is just a glorified mute button that does impact tube life. Treat it as such.
The surge turning on and off your amp is harder on tubes than going to standby though. If I’m going to be away longer than 15 minutes, I turn my stuff off. Other than that, I hit standby.
Standby is just a glorified mute button that does impact tube life. Treat it as such.
this works for me..
311splawndude
Well-known member
This is pretty much what I came to say. I've definitely left the amp on a lot longer. That magic spot between the 'surge' of powering off and on vs. just leaving it on may have a lot to do with the amp (meaning how good of power section it has) and the actual quality of the tubes themselves. Cheap tubes in a Bugera amp for example vs NOS power tubes in a Mesa + level type amp.
Also - don't you mean "Standby is just a glorified mute button that does NOT impact tube life"?
glpg80
Well-known member
Oh no it does impact tube life. You’re indirectly heating the cathode by running current through the tungsten heater wire. The tungsten wire is exactly like old light bulbs and that wire has a rigidity lifespan if current is flowing. The cathodes are also coated and that coating has a finite lifespan that is greatly reduced when electrons are stripped from the cathode when plate current is present, but the exposure to heat also doesn’t help the cathode coating either, albeit not as badly as when the plate current is present.
The only time tube life isn’t impacted is when it’s in a box not exposed to daylight and not turned on.
MadAsAHatter
Well-known member
Two of the biggest myths with the standby switch is that it's a mute button and it protects the tubes/makes tubes last longer. Both of these come from misunderstandings.
People misunderstood the label standby to mean mute when it actually meant standby while the tubes are warming up. So it most certainly is not a glorified mute switch. A true mute switch sends the audio signal to ground. When switching in and out of standby (using as a mute) you're actually switching high voltage in and out the circuit which puts stress on components each time you do it. Why would you want to stress the circuit like that?
Thinking it makes tubes last longer comes from a misunderstanding from an RCA tube manual recommending standby switches for tubes. The manual was actually referring to tubes used with extremely high voltages on large radio station transmitters, not guitar amp tubes. In fact tube manuals say to leave tubes in standby for no longer than 15 minuets or so. Leaving the amp in standby for extended periods (longer than 15 minutes) will put extra stress on and can damage tubes.
The original intent of the standby switch was to solve the problem of how to prevent these new things called capacitors from being hit with voltages outside their max rating and shorting out when using higher voltages from larger power supplies in guitar amps when first turning the amp on. Tubes aren't very good at loading down high voltages when they're not at operating temperature and take a few minuets to get warmed up. When first turning on the amp it would essentially be like the tubes weren't even there and capacitors would be hit with high voltages. The standby switch would remove the high voltages from the circuit while the tubes warmed up and protected capacitors from frying. Once the tubes warmed up you could take it out of standby allowing the high voltage into the circuit. The tubes now at operating temp would properly load down those high voltages so that voltages going to the capacitors would be within their operational range.
Flipping to standby will silence the amp and removes higher voltages going across the tubes. Misunderstanding the standby switch one would think this would help extend tube life. But staying is standby for extended periods is not good for the tubes/amp. And every time you take it out of standby you're immediately throwing high voltages into the tubes and circuit. Doing this back an forth isn't good for the amp/tubes either. By using standby in this manner what you're actually doing in the long run is putting more stress on the tubes and amp circuit; thereby, shortening the lifespan of the tube and possibly causing harm to the circuit.
So to recap
Standby switches are not mute switches and do not protect tubes the way some people think and shouldn't be used in this way. Use the standby switch when first turning the amp on to give the tubes a few minutes to warm up to operating temperatures. If you're taking up to about a 15 min break leave the amp completely on and mute it with an actual mute switch, tuner pedal or just turn the amp volume down. If your break is longer than that turn the amp completely off. Then when you're ready to play again turn it back on as normal in standby and let the tubes warm back up for a few minutes.
*Edit* I want to add that everything above is related to standby switches as they were originally designed and meant to be used. In most cases this all still holds true. As we know quality of components change, things can evolve past their original design and a builder may have designed their specific standby switch to operate slightly differently. So this may not hold true for every single amp out there. If in doubt consult the manual or contact the company to be sure.
People misunderstood the label standby to mean mute when it actually meant standby while the tubes are warming up. So it most certainly is not a glorified mute switch. A true mute switch sends the audio signal to ground. When switching in and out of standby (using as a mute) you're actually switching high voltage in and out the circuit which puts stress on components each time you do it. Why would you want to stress the circuit like that?
Thinking it makes tubes last longer comes from a misunderstanding from an RCA tube manual recommending standby switches for tubes. The manual was actually referring to tubes used with extremely high voltages on large radio station transmitters, not guitar amp tubes. In fact tube manuals say to leave tubes in standby for no longer than 15 minuets or so. Leaving the amp in standby for extended periods (longer than 15 minutes) will put extra stress on and can damage tubes.
The original intent of the standby switch was to solve the problem of how to prevent these new things called capacitors from being hit with voltages outside their max rating and shorting out when using higher voltages from larger power supplies in guitar amps when first turning the amp on. Tubes aren't very good at loading down high voltages when they're not at operating temperature and take a few minuets to get warmed up. When first turning on the amp it would essentially be like the tubes weren't even there and capacitors would be hit with high voltages. The standby switch would remove the high voltages from the circuit while the tubes warmed up and protected capacitors from frying. Once the tubes warmed up you could take it out of standby allowing the high voltage into the circuit. The tubes now at operating temp would properly load down those high voltages so that voltages going to the capacitors would be within their operational range.
Flipping to standby will silence the amp and removes higher voltages going across the tubes. Misunderstanding the standby switch one would think this would help extend tube life. But staying is standby for extended periods is not good for the tubes/amp. And every time you take it out of standby you're immediately throwing high voltages into the tubes and circuit. Doing this back an forth isn't good for the amp/tubes either. By using standby in this manner what you're actually doing in the long run is putting more stress on the tubes and amp circuit; thereby, shortening the lifespan of the tube and possibly causing harm to the circuit.
So to recap
Standby switches are not mute switches and do not protect tubes the way some people think and shouldn't be used in this way. Use the standby switch when first turning the amp on to give the tubes a few minutes to warm up to operating temperatures. If you're taking up to about a 15 min break leave the amp completely on and mute it with an actual mute switch, tuner pedal or just turn the amp volume down. If your break is longer than that turn the amp completely off. Then when you're ready to play again turn it back on as normal in standby and let the tubes warm back up for a few minutes.
*Edit* I want to add that everything above is related to standby switches as they were originally designed and meant to be used. In most cases this all still holds true. As we know quality of components change, things can evolve past their original design and a builder may have designed their specific standby switch to operate slightly differently. So this may not hold true for every single amp out there. If in doubt consult the manual or contact the company to be sure.
Last edited:
311splawndude
Well-known member
I think we are saying the same thing it was just the context maybe. You are saying using the Standby is better than turning your amp on an off again right? Let's put it in the context of recording in a studio. You play. You stop. You listen. You take notes. You step outside and have a smoke. You come back in and play again. And the break is more than 15 minutes each time. Do you leave your amp on standby each time or do you power off and on?
glpg80
Well-known member
Smoke break? Standby. Out to lunch? Turn off. Between sets where turning on/off is risky? Standby.
glpg80
Well-known member
We can agree to disagree - I know the history of where they came from and it started with fender having shit quality voltage rated can capacitors, nothing to do with tubes.
But their implementation today is just what I said, glorified mute buttons.
311splawndude
Well-known member
10-4
I think we are saying the same thing.
So when you say "Standby is just a glorified mute button that does impact tube life." - you are saying it impacts tube life in a good way for short breaks, meaning better than Off and On for short breaks? Correct?
glpg80
Well-known member
Yeah you’re on the right track. Clarifying my statement, Standby impacts tube life negatively, but is not as negative (risky) as turning on or off where transient currents are introduced that can actually cause failure.
Examples of large transient currents are the magnetic fields generating/collapsing with both PT and OT transformers, or filter capacitor banks needing charging or begin discharging through the power tubes. Anytime you introduce transient uncontrollable currents with tubes in circuit means you increase their risk for immediate catastrophic failure, which compared to wear from standby, is worse obviously.
MadAsAHatter
Well-known member
We agree on the history that the standby switch came from Leo using poor capacitors, I just didn't state that outright. If he use better components we probably wouldn't have them now.
We're agreeing on when to turn the amp completely off and not leave it in standby for a long time. Taking a lunch break turn it off. Listening to playback in the studio or break between sets leave the amp on.
I think we're also agreeing that standby switches are pointless, just saying it differently.
You're calling them glorified mute switches. There's no harm in leaving the amp on and hitting standby using it as a mute for breaks. It's better to do that than turn the amp completely off/on a bunch of times.
I'm getting at there's no reason to have one in the first place and you're fine not using it at all. If you want to mute for a break just leave the amp on and skip standby all together. Use a real mute or turn the volume to zero instead That's better than turning the amp completely off/on a bunch of times.
311splawndude
Well-known member
10-4
"Not as negative (risky) as turning off and on" is also what I was saying.
I agree that turning the amp off and on (instead of using the standby) is worse usually.
Question becomes - what is that breaking point where turning it off is better?
I think you were saying somewhere after the 15-30 minute mark?
I would tend to agree, as most would, but was also saying that it could also depend on the quality of the amp/tubes.
MadAsAHatter
Well-known member
@311splawndude @glpg80
Sounds like we're all are in agreement and making near the same points, just saying it differently.
Sounds like we're all are in agreement and making near the same points, just saying it differently.