Why is it called a stand by switch?

el84ster

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I have to disagree with the guy who wrote that sweetwater article, standby will not hurt your tubes. He never explains how or why this would be. Otherwise he makes good points.
 

CB91710

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CS Guitars on YouTube does a great video on stand by switches, explains a lot.

He's a sharp guy and I enjoy his topics.
Unfortunately, I can't stand his thick accent. Very difficult to listen to.
There's an Aussie who does CPAP equipment reviews that I similarly have a hard time listening to.
 

CB91710

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The only use of a standby switch as far as I’m concerned, is the beer break. Keeps the tubes warm and ready to rock when you come back! And keeps it quiet while you’re gone.
Bingo.

Flip the switch and stand by your Les Paul while enjoying a beer so you can make sure the headstock doesn't fly off.
 

Bobby Mahogany

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Learn something every day

I don't give a fuck!
I stand by the "Stand by" switch.

Not too freakin' difficult to understand.
When you go to play your guitar plugged into an amp,
you stand by the Power switch.
So it's like "punching in" at work.
You walk up to the amp and make it known that you are actually there, standing by the amp.
So you activate the "stand by" switch and the amp "knows" you are there getting ready to play.
Then, when you are "really ready", you go from being a "stand by" to being "on" to the gig.

That is all.
Case closed.
(it's always good to close the case when you are done taking the guitar out of the case.)
 

1neeto

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I use it to warm up the tubes, and when I’m done playing I turn it back on to “cool down” the tubes. I know there’s no such thing, but I don’t like the loud pop when I turn off the amp without switching the standby first. Ymmv
 

Recklessrog

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Here is a proper reply to your question with no snide remarks.
The tubes in amplifiers have a finite life, there is a coating on a part called the cathode that when heated is able to give off electrons . When plate (anode) voltage is applied, there is a current that flows through the tube and with no signal, this is called the BIAS. I won't go into how the signal then alters this current as you play, and I'll just stick to the STANDBY function. When you turn on the MAIN power switch, to prevent a phenomenon Known as "cathode Stripping" the tubes should be allowed to have their heaters fully warmed up before the high tension plate voltage is applied. Also, when you are having a break, it is good practice to turn off the Plate voltage so that the tubes are not drawing current and using up the finite amount of cathode coating, this also reduces the heat in the amp which in turn prolongs the life of other components, especially Electrolytic capacitors. THE STANDBY SWITCH IS WHAT TURNS THE hIGH TENSION PLATE VOLTAGE ON AND OFF. Because the heaters are left on at full heat, the amplifier is then ready for instant use by using the standby switch.
If you simply turned on and off the mains power switch, you are stressing the heaters which can lead to premature failure. Same as an incandesant light bulb, the life is mainly determined by how many times is is turned on and off. Left on continuosly, it will last much longer than when continually switched on and off. Probably most of us have seen that a light bulb "blows" as you switch it on when it finally succums to the stress of suddenly heating up.
 
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1neeto

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Here is a proper reply to your question with no snide remarks.
The tube in amplifiers have a finite life, there is a coating on a part called the cathode that when heated is able to give off electrons . When plate (anode) voltage is applied, there is a current that flows through the tube and with no signal, this is called the BIAS. I won't go into how the signal then alters this current as you play, and I'll just stick to the STANDBY function. When you turn on the MAIN power switch, to prevent a phenomenon Known as "cathode Stripping" the tubes should be allowed to have their heaters fully warmed up before the high tension plate voltage is applied. Also, when you are having a break, it is good practice to turn off the Plate voltage so that the tubes are not drawing current and using up the finite amount of cathode coating, this also reduces the heat in the amp which in turn prolongs the life of other components, especially Electrolytic capacitors. THE STANDBY SWITCH IS WHAT TURNS THE hIGH TENSION PLATE VOLTAGE ON AND OFF. Because the heaters are left on at full heat, the amplifier is then ready for instant use by using the standby switch.
If you simply turned on and off the mains power switch, you are stressing the heaters which can lead to premature failure. Same as an incandesant light bulb, the life is mainly determined by how many times is is turned on and off. Left on continuosly, it will last much longer than whencontinually switched on and off. Probably most of us have seen that a light bulb "blows" as you switch it on when it finally succums to the stress of suddenly heating up.
I’m curious. Why some tube amps don’t have a standby switch? I had a 2005-ish Peavey Classic 30 and it didn’t have a standby switch. I would use my tuner pedal as a standby switch, but I always found it odd it didn’t have one.
 

Recklessrog

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I’m curious. Why some tube amps don’t have a standby switch? I had a 2005-ish Peavey Classic 30 and it didn’t have a standby switch. I would use my tuner pedal as a standby switch, but I always found it odd it didn’t have one.
Is it a tube amp? solid state amps don't need one as there is nothing to warm up. If it is a tube amp, then it's for cheapness by the manufacturer, they won't be the ones paying for early tube replacement. Sometimes a little component (called a thermister) is fitted inline with the mains transformer that limits the initial inrush current thereby giving a slower rise in output voltage to the circuits. Not really the proper way to do it with tube amps, but is a cheapskate partial answer to the problem.
 
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efstop

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No one knows why Leo put in a stand by switch, and no one knows why Jim Marshall copied that when he copied everything else on the Bassman.
I grew up with tube radios, TVs and a tube record player. None of those had a stand by switch, and several of my amps have none. The Marshall Origin 5 and Class 5 have no stand by, and I haven't read of any problems related to that since the C5 came out over 11 years ago.

If it makes you comfortable, go ahead and use it. It isn't likely to cause any real damage, except for irreversible cathode poisoning, maybe.
 

CB91710

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Is it a tube amp? solid state amps don't need one as there is nothing to warm up. If it is a tube amp, then it's for cheapness by the manufacturer, they won't be the ones paying for early tube replacement. Sometimes a little component (called a thermister) is fitted inline with the mains transformer that limits the initial inrush current thereby giving a slower rise in output voltage to the circuits. Not really the proper way to do it with tube amps, but is a cheapskake partial answer to the problem.
That's actually backwards.
With a standby switch, the filaments and rectifier (tube or solid solid state) get full power immediately, but the standby switch holds the HVDC back from the plates.
Releasing the standby switch causes full voltage to be released to the plates.
Without a standby switch, the HVDC voltage gradually rises as the rectifier filament heats up (on a tube rectifier).

I've never seen a thermistor in a circuit used to slow the rise of the HVDC, though it woudn't surprise me if it's been done.
 

Recklessrog

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That's actually backwards.
With a standby switch, the filaments and rectifier (tube or solid solid state) get full power immediately, but the standby switch holds the HVDC back from the plates.
Releasing the standby switch causes full voltage to be released to the plates.
Without a standby switch, the HVDC voltage gradually rises as the rectifier filament heats up (on a tube rectifier).

I've never seen a thermistor in a circuit used to slow the rise of the HVDC, though it woudn't surprise me if it's been done.
Laney use thermisters all the time in their amplifiers but mainly to limit the inrush current into the torroidal mains transformer. I don't understand what you mean by "backwards" Nothing I can see in my post is backwards, Maybe you are reading it backwards lol. The correct way of using both the mains and standby switches is..... standby off, turn on mains, wait 30 secs or longer for heaters to warm up fully, turn on standby. Turn standby off during breaks but leave mains on so amp is ready for instant use. P.s. I used to work as a design engineer for a major amplifier manufacturer and spent 50 years in design, developement and repair of electronic equipment right up to mega Watt transmitters, so i think i have more than a slight understanding.
 
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Recklessrog

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Full power all at once not a good thing for capacitors - done!
The standby switch in most amplifiers is after the smoothing and resevouir capacitors so they always get full voltage when the mains is on. With some high power, power supplies, especially with torroidal transformers, a current inrush limiter needs to be incorporated in the line supply circuiit.
 
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efstop

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As I understand it, a guitar amp doesn't use high enough current for a stand by switch to protect the tubes from sudden "high voltage." If your amp is sending 1000V + to the tubes, you have an issue that will likely blow the whole thing to bits.
Stand by? Stand the hell back!
Amplifier tubes are not heated "like a light bulb." They have a separate heater to get the tube hot enough to operate.

Mega Watt transmitters are a different animal from a lowly guitar amp. As such, they no doubt require certain protections in the circuitry.
 

pmonk

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I always turn on my amps in stand by mode and let the tubes warm up a bit before turning stand by off and start palying.

Lesson learned is no more beer breaks
 

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