amplifier standby

[kirkham13]

I was reading a thread over on the GP about standby and its use in tube amps. My understanding is that you only turn it on before shutting off the amp, and then leave it on a couple minutes to let the power drain out. Is this correct?

[strat56]

What you've described is a way to use the standby switch to bleed the capacitors inside the amp of stored voltages.

When turning on your amp the standby switch can/should be left in the standby position for the first 60/90 seconds. This allows the tubes to warm up with just the heater voltage. After 60/90 seconds switch the standby switch to play and full voltage is applied to the tubes and you can play the amp. This is rumored to lengthen the life of your tubes.

Many people also turn standby on if the amp won't be used for a period time, like a break in a live performance to reduce wear on the tubes.

Many people will also argue that when NOS and old tubes were made the manufacturer had no idea what the tubes would be used in and many applications, like TV's and Radio's had no standby switch and that many low wattage amps don't have or had standby switches. In some cases these application without standby switches use/used a rectifier tube that wouldn't allow full voltage across the tubes until the rectifier tube itself was warmed up sufficiently.

You'll get many different opinions on standby switch use. I believe that using the standby switch when turning on an amp only takes 60/90 seconds and if it can extend my tube life, it's not going to hurt anything.

I usually do not put my amps on standby during a break because I can hear a difference in a tube that has been put on standby and is "cold" vs. a tube that has been in play mode for 30 minutes or more and has been throughly warmed up and I prefer the sound of a tube that has been throughly warmed up.

[kirkham13]

So you should put the amp on standby before powering up, and again before powering down ideally?

[Pietro]

I've had some noteworthy tube amp gurus tell me the standby switch is a waste of time on most amps, and that you will increase the life of your tubes if you ignore it... that the only time to use it is if you're taking a break between sets (since so many gear failures happen on power-up and power-down).

Evidently, there is a way to make the standby switch worthwhile, and virtually no amp companies make them that way...

Sorry, I don't remember all the details, as I've been tube-amp-less for a while.

[strat56]

I turn my amp with the standby switch on and wait 60 to 90 seconds and turn standby off. Unless I'm pulling the chassis for something I don't worry about using the standby switch to drain the caps when I'm turning it off so I just flip both switches at the same time.

AS I said you will get many different opinions on how to use the standby switch or if even to use it at all. I'm no expert but my power tubes last a long time.

The technical reason i was given on why it's used on start up is to prevent cathode stripping on the power tubes.

Here's an article on cathode stripping: http://www.chiark.greenend.org.uk/scopes/weyer.txt

[Pietro]

Here's an article on cathode stripping: http://www.chiark.greenend.org.uk/scopes/weyer.txt

i've also heard that this is a non-issue with tube guitar amplifiers.

[dannopelli]

There is all over the board confusion about this. Some guys say to start and stop in standby for five minutes. Of course that is likely overkill.

I think everyone agrees however that since it can't hurt, you might as well power up and down in standby. Some amps won't even fire up unless the standby switch is engaged.

Honestly, I plug my amps up and go to standby as I am setting up the rest of my gear. And I do the same after a gig. At home, my amp goes to standby before I take the guitar out of the case, and I do the reverse when I'm done.

Who knows the truth. But it can't hurt, so that is why I do it. (plus the $80 per hour amp tech in NYC told me to do that, and I have not had an issue since!)

But it is probably best, as Jack does, just to be in Standby for a minute or two, and not leave it on during breaks. Either leave the amp on altogether or not.

[ConnemaraGuitar]

Some stereo tube amps use an "automatic" standby feature that applies voltage to the tube heaters for 45-60 seconds before applying power to the rest of the amp. Timer circuits and relays are used. And no, these do not adulterate the amp in any way since they are confined to the power supply section.

The key point here is the timing: more than a minute of standby when powering up is probably not of any value.

Danno's process is probably perfect, although truth be told, it takes him upwards of 30 minutes to return a guitar to its case, what with the body and neck massage (using a lint-free super soft cloth), gentle wiping of the strings and oiling of the strap (all of which have strap guards installed). Don't tell anyone but I think he buffs out any scratches on the pickguard as well.

This last is offered as good reason to buy a guitar from Danno: it will be in better condition than when it left the manufacturer.

[Pyrrhic Victory]

I always thought standby was for powerup and breaks only.
I've never used it to powerdown. I just shut it off.
Is this wrong? Hasn't seemed to hurt any of my amps so far, but.... don't want to learn the hard way.

[dannopelli]

...Don't tell anyone but I think he buffs out any scratches on the pickguard as well....

MY SECRET IS OUT!

[ConnemaraGuitar]

No reason to believe that simply powering down would be a problem, so long as there is no signal going to the tubes. But if you simply shut off your amp, when will you polish your pickguard? Or freshen the coating on the strings?

I do stand my policy of never departing a building by other than the door through which I entered. Never.