Now that I've been using tube amps for a year or more, I saw in my Mesa manual, and read somewhere else, that you should always turn tube amps on and off via the standby switch. So I've been doing that, i.e. always having the standby switch set to standby before turning the amp on or off.
The other day I forgot and flipped my amp off using the on/off switch and heard a loud pop as she powered down. I don't recall reading about that, so do you folks think it's typical or unusual?
Most all of my tube amps have a standby switch which lets the tubes warm up before using. But a couple of them don't, like my Gibson THOR. When I play through it, I just make sure I turn the volume all the way down before I hit the power switch - otherwise I will get the "pop".
I´d stick to the manual, but wouldn´t worry about a pop - at least it´s not unnatural.
But as long as you are aware of the correct routine, the amp is safe in your hands I think.
However, I find it strange that many people are lazy on the stand by routine, but still complain about tube prices.
It really is a difference, specially with tubes of a lesser quality.
I have built a 20w DR combo for our guitar player, and trained him to use the switch.
If he powers down now and forgets to use the stand by switch, he gets that frightened look on his face, like the amp is gonna blow up :mrgreen:
The old rule that I always lived by ,was turn on using the standby and off with the on/off switch.
Rick
Quote from: rahock on November 08, 2013, 05:33:37 AM
The old rule that I always lived by ,was turn on using the standby and off with the on/off switch.
Rick
I think a lot of people have no clue which order to use the switches...so they may be self-defeating in some cases.
The theory in the on w/standby was to build heat gradually and warm things up and not push cold components. The off with the on/off switch was supposed to release the heat quicker, which is what I was told, is what you want to do. The cool down will be gradual enough though the off switch to pose no danger. After you turn it off with the off switch, then you flip the standby , so it will be ready for the next time you start the amp.
Rick
That's what I was told many years ago too.
Quote from: Dave W on November 08, 2013, 09:38:39 AM
That's what I was told many years ago too.
Back when we heard that story, electricity was still pretty new. So, I know it worked with old electricity, but with this new electricity that they're using these days, it might be different ,and I have no idea if it would work right for metal :P.
Rick
Quote from: rahock on November 08, 2013, 04:25:20 PM
Back when we heard that story, electricity was still pretty new. So, I know it worked with old electricity, but with this new electricity that they're using these days, it might be different ,and I have no idea if it would work right for metal :P.
Rick
I remember old electricity. The electrons ran uphill both ways.
And we were damn thankful we even had electrons. Yep, those were the days ;D
Rick
Standby off - power on - standyby on - use - stop using - standby off - power off...
Works by me...
The THUMP will eventually kill some speakers, sometimes... had a Marshall that did that...
Quote from: rahock on November 08, 2013, 05:33:37 AM
The old rule that I always lived by ,was turn on using the standby and off with the on/off switch.
Rick
+1
I flipped the Standby on first, then after a warm-up period, flipped the On switch. If I was leaving for a few minutes I left Standby in the on position and flipped the On switch off...leaving it in Standby. When leaving for the day, I flipped the Standby switch off.
Quote from: Pilgrim on November 10, 2013, 04:18:49 PM
I flipped the Standby on first, then after a warm-up period, flipped the On switch. If I was leaving for a few minutes I left Standby in the on position and flipped the On switch off...leaving it in Standby. When leaving for the day, I flipped the Standby switch off.
I'm thinking not all standby switches are labeled the same. I currently have two tube amps with a standby function. Amp number one, has two switches. The first is a two position line reversing on/off switch with top and bottom positions "on" and center position "off". The second is the standby switch with bottom position "off" , meaning no sound comes out of the amp, and the top position is "on" , meaning in this position, sound does come out of the amp. The standby switch does nothing unless the on/off switch is turned on. So, "standby off" actually means the standby function is "on" (no sound), and "standby on" means no longer in standby function (amp on and ready to produce sound).
Amp number two , has one rotary switch with two "on" positions and one standby position. No need for two switches. A yellow light indicates the amp is turned on and in standby mode(no sound comes out). Turn the switch to "on" and a red light comes on, the yellow light goes out and sound comes out of the amp. No guesswork to figure the meaning of on and off.
Rick
I sold my old Bassman head and I don't remember which switch left the red pilot light on.
And typing "which switch" reminds me of a Danny Kaye routine...which included the line "Which witch switch should the Ipswich witch twitch?"..a play on an old tongue-twister. I miss Danny Kaye. http://www.wowowow.com/liz-smith/liz-smith-danny-kayes-centennial-year/
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.
Quote from: lowend1 on November 11, 2013, 10:19:54 AM
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?
Quote from: lowend1 on November 11, 2013, 10:19:54 AM
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!
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.'
Quote from: amptech on November 12, 2013, 02:05:46 AM
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.
Quote from: Psycho Bass Guy on November 12, 2013, 02:40:14 AM
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?
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.
Quote from: Psycho Bass Guy on November 12, 2013, 09:14:25 AM
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.
Quote from: drbassman on November 12, 2013, 09:26:07 AM
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.
Quote from: dadagoboi on November 12, 2013, 10:17:29 AM
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?
Quote from: drbassman on November 12, 2013, 10:32:10 AM
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.
Does turning down your volume stop the pop?
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?
Quote from: Psycho Bass Guy on November 12, 2013, 03:48:00 PM
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.
Quote from: drbassman on November 12, 2013, 04:46:19 PM
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.
Quote from: Psycho Bass Guy on November 12, 2013, 06:43:19 PM
That's what I said to do. I think we got our wires crossed somewhere.
Right, I was doing that and eliminated hearing the pop when shutting down. I was just curious to know if the pop is sign of a problem or a design quirk. As for crossing wires, I think they are in my brain, not the amp! Chemo saves your ass but fries your brain! Ain't medicine wonderful? Yep, it is!
Chatted with the techie from Mesa (in California) today. He said the pop is normal with the Prodigy and that I should hit the standby switch first before powering down. I asked him if this was a design thing and he said yes, but obviously didn't want to tell me just what. Probably just as well, he would only have confused me! I'm trusting him at this point and plowing forward. The amp is working great.
Tried a bass out at the shop today on one of those new Fender Bassman all tube amps and guess what happened when I shut it off? POP! I felt right at home. :)