Turn on, turn off

[lowend1]

IIRC, the standby is there to protect the tubes from something called "cathode stripping", and therefore extending tube life. I've always been told that if the amp is not used frequently, the consequences of not using the standby are negligible. FWIW, both of my 70s Orange 120 heads came from the factory without a standby - as did most Oranges from the early days. Also, I rarely use the standby on my '72 SVT, and the original Magnavox-branded TungSol 6550s are still in very good health. YMMV

One thing I HAVE always done whenever possible is allow the amp to reach room temp before turning it on, and if that is not an option, let it warm up in standby mode.

[amptech]

IIRC, the standby is there to protect the tubes from something called "cathode stripping", and therefore extending tube life. I've always been told that if the amp is not used frequently, the consequences of not using the standby are negligible.

Negliable maybe, but as long as using the standby is the preferred way to do it, theres no reason why you should skip that routine?

FWIW, both of my 70s Orange 120 heads came from the factory without a standby - as did most Oranges from the early days.

Well, that's a well known design error. I've standby modded many Oranges. Last one was a guy who had installed a set of EH-EL34's himself, bought online. They broke down in a couple of weeks. (it has non adjustable bias, so they were probably running hot as well) Did a stand by job and biased the amp for a good set of tubes (winged c's) , and the amp's been doing fine now for some years.

Amp's with a rectifier tube are 'slower' than a regular ss diode bridge, it acts like a stand by switch by not presenting full voltage to the anode's of the output tubes before the cathode has (at least) started to warm up. But still it is better to use the switch, it's there for a reason!

[Psycho Bass Guy]

Guitar tube amps tend to be more forgiving of standby switch(ery). Anything with a tube rectifier doesn't really need one anyway because there's no high voltage on the main power bus until the rectifier tube warms up. As many others have said, the correct way to power on a tube amp  is to put it in 'standby,' turn the power on and give the amp 30 seconds to a minute to warm up, then flip the standby switch to 'run.' Upon powering down, leave the standby switch to "run" and even 'play down' the amp as it cools. You'll hear the volume drop drastically and the sound become progressively more distorted as the filter caps bleed down. This helps to prolong cap life and is negligible to the tubes. Several hifi and large tube amps (the SVT CL, all the Trace tube stuff, etc) have relays on the high voltage bus line that don't open until the tubes are warmed up enough for safe operation, so even though they have standby switches, there's no way the amp can be brought up 'cold.'

[lowend1]

Negliable maybe, but as long as using the standby is the preferred way to do it, theres no reason why you should skip that routine?

Point taken. I use the standby on almost all of my amps. In the case of the SVT as well as the one Orange that has been standby modded, the switches are on the back of the head. Positioned as they are - lined up with other amps either alongside or stacked - getting at the standby is a logistical nightmare.

[drbassman]

Guitar tube amps tend to be more forgiving of standby switch(ery). Anything with a tube rectifier doesn't really need one anyway because there's no high voltage on the main power bus until the rectifier tube warms up. As many others have said, the correct way to power on a tube amp  is to put it in 'standby,' turn the power on and give the amp 30 seconds to a minute to warm up, then flip the standby switch to 'run.' Upon powering down, leave the standby switch to "run" and even 'play down' the amp as it cools. You'll hear the volume drop drastically and the sound become progressively more distorted as the filter caps bleed down. This helps to prolong cap life and is negligible to the tubes. Several hifi and large tube amps (the SVT CL, all the Trace tube stuff, etc) have relays on the high voltage bus line that don't open until the tubes are warmed up enough for safe operation, so even though they have standby switches, there's no way the amp can be brought up 'cold.'

Start up makes sense, but should you lower the volume knob to 0 to avoid the pop on power down?

[Psycho Bass Guy]

There shouldn't be a pop at all, especially if you're playing down the caps. If cutting power makes the output pop, there's something wrong. Besides, the volume knob would have no effect on that.

[drbassman]

There shouldn't be a pop at all, especially if you're playing down the caps. If cutting power makes the output pop, there's something wrong. Besides, the volume knob would have no effect on that.

OK, I'm showing my ignorance here.  What exactly do you mean by playing down the caps?  Basically, if I just turn my Mesa off after playing for a bit (no standby switch engaged), as she cools down there's a loud pop after a few seconds through the speakers.  That's not what I expect.  What's the amp telling me here?

Also, if I turn the volume to 0 before turing the amp off, you don't hear the pop.

[dadagoboi]

OK, I'm showing my ignorance here.  What exactly do you mean by playing down the caps?

Just keep playing as you switch off.  Back in the day one of my Coliseums had been modded with power caps that were aerospace surplus.  They were each about 8 inches long and 2 inches in diameter, filled up the inside of the box.  I could play the amp with decent volume for around 30 seconds after switching off.  I've wondered what the next guy that opened that amp thought when he saw them.

[drbassman]

Just keep playing as you switch off.  Back in the day one of my Coliseums had been modded with power caps that were aerospace surplus.  They were each about 8 inches long and 2 inches in diameter, filled up the inside of the box.  I could play the amp with decent volume for around 30 seconds after switching off.  I've wondered what the next guy that opened that amp thought when he saw them.

Thanks Carlo, it means what it says!  Duh.  BTW, do you think I've got a problem if the amp pops on shut down?

[dadagoboi]

Thanks Carlo, it means what it says!  Duh.  BTW, do you think I've got a problem if the amp pops on shut down?

Anthony knows a lot more than I do but on a brand new over $2k amp...Hell, yeah.

[Psycho Bass Guy]

Does turning down your volume stop the pop?

[drbassman]

Does turning down your volume stop the pop?

Yes it does.

[Psycho Bass Guy]

You've got something in the MV circuit that's causing that. Knowing Mesa, it's probably a relay normally used for channel switching being used for output stage protection. Does the amp do it if there's no bass connected to the input?

[drbassman]

You've got something in the MV circuit that's causing that. Knowing Mesa, it's probably a relay normally used for channel switching being used for output stage protection. Does the amp do it if there's no bass connected to the input?

I left it at the club, I'll check and let you know.  It also doesn't pop if I leave the standby switch on and flip the on switch to off.

[Psycho Bass Guy]

It also doesn't pop if I leave the standby switch on and flip the on switch to off.

That's what I said to do. I think we got our wires crossed somewhere.