Proper Usage Of Standby Switch

[Spherion]

I've researched a bit and am seeing some contradictory opinions regarding the proper usage of the standby switch on tube amps.

I've read that you put the standby switch on, wait a few minutes, turn power on and reverse the order when shutting down. I've read that you power off with the standby switch still on.

From what I can tell the order specified below is the proper way. Is this correct?

"The purpose of the "standby" switch is to allow the output tubes to heat up fully before they see any high voltage. The tube's "cathodes" can be worn out prematurely if not fully heated and the tube is conducting.

Powering On

1. Verify STANDBY switch is set to ON position.
2. Set POWER switch to ON position.
3. Wait 1 - 3 minutes.
4. Set STANDBY switch to OFF position

Powering Off

1. Set STANDBY switch to ON position.
2. Wait 30 second to 1 minute.
3. Set POWER switch to OFF position.

This practice will give your set of tubes a much longer life."

 

[Boogiebabies]

I think you have it backwards their chief. Switch procedures.

Power on - Standby off for 1-3 minutes, then On.

Power Off - Standby off for a cool down, then turn the power off.

 

[Spherion]

See, the Triple Rectifier manual says the opposite. I'm so confused!!

Quote from Manual:

"7.) Flip the POWER switch to the ON (up) position and wait at least 30 seconds for the power tube filaments to warm up with the STANDBY switch in the Standby (OFF/down) position. This cold start procedure prolongs tube life substantially if it is followed each time your amplifier is powered up.

8.) Turn the OUTPUT Control off or to a very low setting before flipping the STANDBY switch to the ON (up) position. This will prevent accidental settings that are too loud for the room or your ears. These amplifiers are capable of extremely loud volumes and should be used with care to avoid damage to your hearing. Starting each power up with the OUTPUT Control zeroed will help to eliminate painful and/or embarrassing situations.

9.) Flip the STANDBY switch to the ON (up) position and enter the world of Rectosis."

 

[AdmiralB]

The only thing to be concerned about is power-up. Turn on the mains switch and let it warm up a minute before going off-standby.

On shutdown, it makes no difference. I shut down the mains and leave standby in 'operate', because I know it will fully drain the filter caps.

 

[Boogiebabies]

Sorry, I did not get to finish.

If you flip the standby to on too quickly it causes cathode stripping and wears the tubes out. The heaters prevent some of this. I generally like my tubes to have a few minutes to cool down naturally before killing the power.

 

[Spherion]

Okay, so the procedure would be as follows?

"Powering On

1. Verify STANDBY switch is set to OFF position.
2. Set POWER switch to ON position.
3. Wait 1 - 3 minutes.
4. Set STANDBY switch to ON position

Powering Off

1. Set STANDBY switch to OFF position.
2. Wait 30 second to 1 minute.
3. Set POWER switch to OFF position. "

It kinda seems like the standby switch being OFF is backwards. You'd think that turning ON the standby switch would warm up the tubes as opposed to the opposite.

 

[MusicManJP6]

Sounds about right to me, boogiebabies...

 

[Boogiebabies]

Sounds about right to me, boogiebabies...

Me too. Also, as the Admiral pointed out, turning it straight off will discharge the caps. You may hear a fart or burp from the speakers, but it's fine.

 

[AdmiralB]

Yeah, it's fine to just turn it off. There's no difference in the cool-down.

Also, I never use standby for anything other than warmup. On breaks, leave the amp on and muted. Extended standby causes cathode poisoning and shortens tube life.

 

[srf399]

Also I don't move the amp until the tubes have cooled down

 

[AdmiralB]

What's the longest or best/recommended amount of time to leave in standby for warmup before turning amp on?

what is cathode poisining? never heard of that...

A minute or two is fine. I wouldn't leave an amp on standby longer than ten minutes or so...won't hurt the amp, just the tubes.

Cathode poisoning is a condition caused by heating the cathodes but not pulling any electrons from them. The cathode tends to build a 'crust' that reduces its ability to emit.

 

[mrd]

I usually just flick my standby on for a minute, then full power after that. When I turn off, I turn off hi volts, then the mains afterwards.

Some amps have their switches labelled differently. For instance, the Mark IV you turn on the "power" first, then flick it out of standby, which sort of seems counter-intuitive cuz you'd think you would want to have it in standby first, THEN get the power going. On the Road King it's different too, just two switches called AC Mains and Hi Volts.

Basically, all you need to know, is get power from your wall into the amp, warm everything up, then flip the switch that allows the output transformer to start working. Just make sure you have a load on there, eh?

Anyway, if you're in doubt, just check the manual, every Mesa manual I've ever seen has very specific instructions on how to turn your amp on and off and what NOT to do, etc.

 

[danvortex]

Great infos. Got another question. When playing live, i often let the opening acts use my cab and i turn the power on for about 1/2 hour before we start our set, most of the time the cab is not connected to the amp... I just learned that it is not good to let it on standby for so long so am I better to also turn the standby on ?? Would it hurt the amp to have it all ON without a cab connected to it ??? If yes than how can i get the amp to really warm up before playing our set ? I'm not sure it would be at its best from the very beginning of our show if i was warming it up for only 3 minutes...

 

[AdmiralB]

I wouldn't do that. The Dual Rectifiers - at least the two-channel amps - and the TOV are unstable without a load attached.

Most amps, if there's no input, can run OK with no load attached. Not these.

 

[Charlie]

I'm 99% sure it's ok to turn the amp on *while it is in standby mode* without a load attached.

I never do it though... seems like a really bad habit to get into.

 

[AdmiralB]

I'm 99% sure it's ok to turn the amp on *while it is in standby mode* without a load attached.

Sure. But that's not what he asked.

 

[AdmiralB]

solid thread:

Leaving Amp On During Breaks-Yes Or No
http://www.talkbass.com/forum/showthread.php?t=2365

Except for the part about cathode bias...bias is there immediately with cathode bias, the cap only affects AC, not DC. Fixed-bias amps DO take some time to fully develop bias voltage, and it is cap-dependent, but it's not longer than 30 seconds or so to reach 'safe' levels.

 

[Restless Rocks]

What's the longest or best/recommended amount of time to leave in standby for warmup before turning amp on?

what is cathode poisining? never heard of that...

A minute or two is fine. I wouldn't leave an amp on standby longer than ten minutes or so...won't hurt the amp, just the tubes.

Cathode poisoning is a condition caused by heating the cathodes but not pulling any electrons from them. The cathode tends to build a 'crust' that reduces its ability to emit.

Hmmmmmmmmmmmmmmmm!!!!!!! I don't think that most places I play are going to allow me to shorten my breaks from 20 or 30 minutes down to less than 10 to prevent "cathode crusting" which is a term completely new to me. I would be eager to learn more about this condition. But let's just say that I got my cathodes crusty. Could I not simply strip this crust by powering on my amp with the standby "off" on occasion. Okay yes I'm being a smart *** Admiral but on the serious side could you give us a source of info on this subject? This ole dog loves to learn new tricks.

 

[AdmiralB]

I don't think that most places I play are going to allow me to shorten my breaks from 20 or 30 minutes down to less than 10 to prevent "cathode crusting" which is a term completely new to me.

Don't shorten your breaks. Leave the amp on.

Here's a good illustration of it, although on nixies, the same concept applies to us:

http://www.tube-tester.com/sites/nixie/different/cathode%20poisoning/cathode-poisoning.htm

Like the article says, it's possible to 'burn off' the 'crust' (and occasionally temporarily rejuvenate old tired tubes) by feeding the filaments with significantly higher-than-standard voltage.

 

[Restless Rocks]

Thanks Admiral, interesting info. I'm wondering if the life expectancy of most modern made tubes is such that the actual damage would become noticable before their replacement. Hell I forget to turn my amp on to standby most breaks anyway when I just back my volume pedal down. (The badonkadonk over by the bar is distracting to a guy trying to get the most out of a set of tubes.) Until they make a standby switch that's completely "child proof" most of us will not get the proceedure right all the time anyway. Thanks for the advice. More technical links are always appreciated too.

PM