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Leaving tube amps on, bad idea?

stratzrus

Philadelphia Jazz, Funk, and R&B
Gold Supporting Member
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22,956
Is it bad to leave tube amps on for hours at a time?

I know in the audiophile world tube power amps are left on for days at a time, both for the best tone and with the notion that the process of turning them on and off, heating and then cooling them repeatedly, puts more wear on them than just leaving them on.

Is the same true for guitar amps?

If I'm going to play off and on during the course of the day (two or three half hour sessions in the morning and the same in the afternoon and evening) should I turn the amp off each time I stop or leave it on until done for the day?
 

WillLane

Member
Messages
2,225
If the amp has enough time to cool down between sessions, turn it off. There's no reason to leave it cooking for hours when it only takes a few minutes to cool down.

What you probably don't want to do is play it for a minute, turn it off for a minute, then play it for a minute again, then turn it off for a minute again... etc
 

tmac

Goldmember
Platinum Supporting Member
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2,268
Turn them off when you’re going to be away for more than 30 minutes would be my operator procedure. Don’t leave them in standby either, for more than 30-60 minutes. Just my opinion. I’ve left em in standby overnight and just forgot to turn it off.
 

Suave Eddie

Member
Messages
11,657
Old tube driven civil defense stations were left on for years from what I've heard.

As long as you amp is well ventilated and not in danger of excessive heat buildup it's probably fine.
 

-CM-

Something Clever Here
Gold Supporting Member
Messages
2,059
Is it bad to leave tube amps on for hours at a time?

I know in the audiophile world tube power amps are left on for days at a time, both for the best tone and with the notion that the process of turning them on and off, heating and then cooling them repeatedly, puts more wear on them than just leaving them on.

Is the same true for guitar amps?

If I'm going to play off and on during the course of the day (two or three half hour sessions in the morning and the same in the afternoon and evening) should I turn the amp off each time I stop or leave it on until done for the day?
I've owned Audio Research tube amps since the 90's and have never left them on other than when I am using them. But my Classic 30 did actually malfunction recently, so yes, I guess powering the amp on and off thousands of times probably did it in.

But guitar amps typically have a standby switch which keeps the tubes warm but not powered. Is this true for yours?
 

8len8

Silver Supporting Member
Messages
14,672
You need to determine how long it takes the amp to warm up till it sounds it’s best, and if you’re willing to wait that long every time you turn it on. That, versus shorter amp/tube life span.
 

stratzrus

Philadelphia Jazz, Funk, and R&B
Gold Supporting Member
Messages
22,956
You need to determine how long it takes the amp to warm up till it sounds it’s best, and if you’re willing to wait that long every time you turn it on. That, versus shorter amp/tube life span.
But that's my question, will leaving it on for four to six hours at a time really shorten the tube life span more than turning it off and on five or six times a day?

Also, how long should you leave it in standby when warming up? I usually leave it on standby for a minute or so. What's the best practice?

Old tube driven civil defense stations were left on for years from what I've heard. As long as you amp is well ventilated and not in danger of excessive heat buildup it's probably fine.
That's what I was thinking. I started this thread just in case I was wrong.

I've owned Audio Research tube amps since the 90's and have never left them on other than when I am using them. But my Classic 30 did actually malfunction recently, so yes, I guess powering the amp on and off thousands of times probably did it in.

But guitar amps typically have a standby switch which keeps the tubes warm but not powered. Is this true for yours?
Yes, mine has a standby switch but I've read (and if it's on the internet it must be true) that leaving an amp on standby for lengthy periods of time is bad for the tubes.
 

Bandit127

Member
Messages
121
But guitar amps typically have a standby switch which keeps the tubes warm but not powered. Is this true for yours?
There is much debate about leaving guitar amps on standby for anything other than startup. If there is a concensus it is that it is undesirable. Standby leaves the heaters on and electrons boiling off the cathode while there is no high voltage to make the tube conduct and that being undesirable some sense to me.
 

Bandit127

Member
Messages
121
If you want to know how long to leave it in standby for, power it up without standby and a source running. Time how long it takes to make sound and that is how long to leave it in standby. A minute or so IME.
 

hogy

Silver Supporting Member
Messages
13,968
Back in the day when tube technology was much more common, tube equipment was classified as "continuous use" or "intermittent use".

Things like school PAs, intercoms, radios and HiFi gear were "continuous use", and designed to stay on indefinitely.

Guitar amps were not.
 
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SRT2011

Silver Supporting Member
Messages
2,118
I never leave my tube amps on for hours at a time when not in use, but that's just me.
 

-CM-

Something Clever Here
Gold Supporting Member
Messages
2,059
There is much debate about leaving guitar amps on standby for anything other than startup. If there is a concensus it is that it is undesirable. Standby leaves the heaters on and electrons boiling off the cathode while there is no high voltage to make the tube conduct and that being undesirable some sense to me.
"If there is a consensus is is that" is brilliant! So much more authoritative than "I think" or "in my opinion" and yet the same.

Yes, mine has a standby switch but I've read (and if it's on the internet it must be true) that leaving an amp on standby for lengthy periods of time is bad for the tubes.
What does the amp manual say?
 

WillLane

Member
Messages
2,225
What does the amp manual say? [about the standby switch]
Using the standby switch on an AC30TBX can blow the tube rectifier. I'm certain the manual doesn't mention that. :rotflmao
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Standby switches on an amp with a tube rectifier are generally not needed, as the rectifier won't start passing high voltages until the tubes (like the rectifier) are warm. But most of time, they're harmless or at least should be. For a SS rectifier, I'd use the standby switch until the amp has warmed up so the tubes aren't getting blasted with high voltages before they're hot.

Some people argue it doesn't matter, just like people say it doesn't matter if you leave your tube guitar amp on or not. Since there is so much conflicting information, I say to err on the side of caution. And since I've known some people to leave their amps on and they always sound bad and worn, I feel more comfortable in my decision.
 




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