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Amp off vs standby for long break?

Okctodd

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Jul 27, 2020
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Okay, I know it's tubes cycling hot/cold that does damage to (tubes and SS). I've been practicing for 2.5 hours; I'm gonna take 90 minute break, maybe more. Should I power off or leave it on standby for perhaps 2 hours? Am I pissing away more electricity and or tube life by not just powering off for 1.5 - 2hours?
 

DutchRay

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Mar 15, 2015
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463
Tube life will not be seriously effected by leaving the amp on Standby, but it will still need electricity (although less than when you leave it On). I found that tube amps change tone a bit when they've been operating for an hour or so, some like the cold amp sound, some like the warm amp sound. My Deluxe Reverb get less gainy after about 45 minutes, so when we take a short break I usually leave it in Standby but if the break is more than 15 minutes I'll shut it down. I see no reason to leave a solid state amp On when not in use.
 

PaulD

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Jun 25, 2007
Messages
590
There is an awful lot of misinformation and bullshit around about standby switches, they are completely unnecessary on guitar amplifiers and leaving an amp on standby for extended periods of time can indeed have a detrimental effect on valve life due to a phenomenon called cathode poisoning which affects the oxide coating on the cathode. There is no real problem with using them for short periods of time (half an hour or so) but for longer periods I would recommend turning the amp off (or leaving it on with nothing plugged in if you don't care about using the electricity!).

As for all the bullshit about switching the power switch on and waiting several minutes before switching the standby on - it is exactly that, bullshit! Just switch them both on together and switch them both off together, it will do no harm and there are some sound technical reasons why it is actually better for the valves to do it this way. There is some good information on the subject here http://www.valvewizard.co.uk/standby.html
 

Phoenician

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Oct 12, 2020
Messages
60
Standby switches make a handy mute switch.

Out of habit, I turn the amp on while in standby and later flip the standby switch after I’m plugged in and ready to go. I flip it off while changing guitars or leaving the room. I flip the standby off when I’m done playing and I’m putting the guitar away. I turn the amp off when I’m unplugging and packing up.
 

PaulD

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Jun 25, 2007
Messages
590
Standby switches make a handy mute switch.

Absolutely but a simple mute switch that grounds out the signal path is a far better way to achieve this than switching off the HT voltage which is what a standby switch does. Another issue with standby switches is that more often than not the manufacturers will use a normal mains rated switch which were never designed (and are usually not rated) to switch high voltage DC current. When switching high voltage DC you get an arc between the switch terminals whenever it is switched on or off, this can cause premature failure of the switch. I have replaced many failed standby switches over the years, some of them on amps only a few years old, and I always advise customers to leave them switched on. If they require a mute function I will suggest modifying the amp to replace the standby switch with a mute switch, it is typically a fairly simple mod.
 

Phoenician

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Oct 12, 2020
Messages
60
Absolutely but a simple mute switch that grounds out the signal path is a far better way to achieve this than switching off the HT voltage which is what a standby switch does. Another issue with standby switches is that more often than not the manufacturers will use a normal mains rated switch which were never designed (and are usually not rated) to switch high voltage DC current. When switching high voltage DC you get an arc between the switch terminals whenever it is switched on or off, this can cause premature failure of the switch. I have replaced many failed standby switches over the years, some of them on amps only a few years old, and I always advise customers to leave them switched on. If they require a mute function I will suggest modifying the amp to replace the standby switch with a mute switch, it is typically a fairly simple mod.
Does the mean you leave the standby switch on all the time and just use the power switch for on and off?
 

TM1

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Jun 27, 2003
Messages
8,135
I've worked on Tube/Valve amps for 31 years and I think using the Standby does more harm to the output tubes/valves with the power surge than just letting them stay on..
 

LyleGorch

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Aug 17, 2018
Messages
108
On one of my amps, its off, standby, and on. The guy who built it said standby 15 secs. then on.
 

Unbound Dot Neck

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Jun 14, 2004
Messages
1,615
Accidently , left my 65 DR in stand by over night, all the original electro power caps leaked badly
Its was time.. silly me
 

ourmaninthenorth

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Mar 28, 2009
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6,760
Does the mean you leave the standby switch on all the time and just use the power switch for on and off?
I was given similar advice many years ago that PaulD is suggesting, standby always on, and power for on and off.

No idea as to the technical reason, but it's simply become a habit with standby switches.
 

garywright

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Aug 17, 2002
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14,236
with Leo Fender supposedly being so frugal why do you think he installed an unnecessary feature?
 

PaulD

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Jun 25, 2007
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with Leo Fender supposedly being so frugal why do you think he installed an unnecessary feature?

The most likely reason is that the voltage rating of the filter capacitors on the early Fender's was marginal and using a standby switch may have helped to avoid the caps going over voltage during warm up (perhaps the cost saving of using lower rated capacitors outweighed the cost of the extra switch - who knows?). There is some good information and a discussion of the reasoning on the Valve Wizard website that I linked to in post #3.
 

LeonC

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Aug 30, 2002
Messages
426
Folks...you also need to recognize that all standby "circuits" don't use the same type of design. In most modern amps, the standby switch interrupts the high voltage (B+) line supplying the plates on the tubes. But not all standby circuits do that. For example, virtually all old Valco-made amps (Valco, Supro, Gretsch, Pencrest, Atlas, Vega, National, etc. etc.) used a totally different technique and had nothing to do with the B+ line (it involved canceling out the signal to the grids on the power tubes). Early on, other brands of amps used other techniques in their standby circuits. So, as with most things in life, you don't want to make (or listen to) sweeping generalizations...
 

PaulD

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Jun 25, 2007
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Folks...you also need to recognize that all standby "circuits" don't use the same type of design. In most modern amps, the standby switch interrupts the high voltage (B+) line supplying the plates on the tubes. But not all standby circuits do that. For example, virtually all old Valco-made amps (Valco, Supro, Gretsch, Pencrest, Atlas, Vega, National, etc. etc.) used a totally different technique and had nothing to do with the B+ line (it involved canceling out the signal to the grids on the power tubes). Early on, other brands of amps used other techniques in their standby circuits. So, as with most things in life, you don't want to make (or listen to) sweeping generalizations...

A switch across the phases that cancels out the signal would be considered a mute switch not a standby switch. The term "standby switch" as it relates to guitar amplifiers is generally accepted to mean a switch that turns the HT supply on and off.
 

LeonC

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Aug 30, 2002
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426
A switch across the phases that cancels out the signal would be considered a mute switch not a standby switch. The term "standby switch" as it relates to guitar amplifiers is generally accepted to mean a switch that turns the HT supply on and off.
We can call these "mute" switches if you like...but they were typically labeled "Standby." Recognizing that they work on entirely different principle is something that only people who understand the underlying circuitry will recognize.
 

J T

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Oct 20, 2005
Messages
10,188
On my 94 Matchless, there's no such thing as a "standby". It's just On or Off
:cool:

IMG_20220120_134137706 copy.jpeg
 
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