Left amp on standby for two days

[Pvglover]

Hello

I'm a brand new member looking for help, please.

Very stupidly, I left my DC2 in standby mode for over two days. When I discovered my error and flicked the amp into play mode I found that the channel that had been selected was extremely noisy (like radio static) whilst the other channel seemed OK.

Do I just need to swap the preamp tubes for the affected channel or is it likely that I've done more serious damage?

Any advice very gratefully received.

(BTW discovering this forum is one good thing that has come out of this problem)

 

[Charlie]

I'm pretty sure standby only effects the power tube - I'm sure somebody will chime in with some more knowledge though.

Anyway... you're not the first person to do something like this.



The amp should be ok I'd try swapping some preamp tubes out and see if it fixes the problem.

 

[dmcguitar]

i have left it on over night, and it has done no damage. I believe charlie is right, leaving it on standby will have the idle current running though you power tubes. so its like you left a light bulb on for 2 days you wasted electricity and wore them out a little more, but unless they were dying i wouldnt worry about it.

 

[simonich]

When an amp is on standby the main voltages are NOT on. There is no idle current flowing anywhere. What is on are the heaters for the tubes, which is simply a small DC voltage.

Leaving it on standby won't do any damage to the amp. There has been some discussion here about cathode poisoning due to too much standby time, though YMMV with that experience. Do a search in this forum if you want more info on that one.

 

[Pvglover]

Thanks to all of you for the helpful advice.

My big concern is the "static" noise that the amp is now producing. I did a search on the forum around cathode poisoning, as suggested by Simonich, and this symptom seems to be consistent with a range of significant problems.

 

[Charlie]

I'd get a few spare preamp tubes, which are good to have around anyway, and try swapping them all out one by one and see if that fixes the problem. I'd also check all of your cables just to be sure as well as your power supply.

Good luck.

 

[Anonymous]

yes agree, it sounds as if your tubes are getting microphonic.
change piece by piece to new ones and the noise should be gone

 

[MrScary5150]

thats crazy

 

[fishyfishfish]

I forgot and left my LSC on for a week with the cover on! No problems, but now I am a heck of a lot more careful!

 

[phyrexia]

I left my Mark III on full power for 16 hours the other day and my AC15 on standby for the same amount of time.

No harm no foul.

Is it the lead channel that's making the noise?

 

[Pvglover]

thanks for all the responses. I will change the preamp tubes as suggested.

The problem is with the rhythm channel - which was the one selected during the two days. I think my decision to power the amp up rather than turning it off to cool down perhaps caused the problem(?) The static problem has since proved to be intermittent.

 

[Mullenski]

Did that once and ended up needing a new cap (?). No biggie, but did involve $20 and soldering by a tech.

 

[edward]

A well-designed/executed amp (like our boogs ) should have zero issues with being left on full power, let alone just on standby. If you are experiencing noise, then a tube was on the outs already ...nothing to do with the amp, per say. Remember that tubes do have a usable life, and cheaper/new-production tubes even shorter than NOS. This just may be your "opportunity" to expeiment with some different flavors

Edward

 

[EL84]

Hell, I've left tubes amps in stand-by mode for months on end if not a year. Only turned it off if I had to move it.

 

[soundpurist]

:lol: This is Rick Onslow. I know this tech, he's living in Montreal. I only realized it when i looked up. That's weird i just googled the question...


Q: I left my amp on (not on standby) overnight. What kind of damage this will do to my amp? (Morgan H)

Leaving your amp on continously is not a problem if there is adequate ventilation. It is more damaging to turn the amp on and off frequently than it is to leave it on. Power tubes are like light bulbs and their lifetime is rated in hours. This rating decreases the more they are switched on and off. Radio stations still use very high power tubes to transmit their signal and they leave them on 24 hours a day.

It's a question of metal fatigue caused by constantly changing the temperature of the elements in the tube. As they expand and contract the metal weakens causing the tube to become microphonic and stressing the welding points that join the elements together. Eventually the element can break off or cause a short. When the amp is on standby there is no plate current but the heater filament is still on in order to keep the tubes warm. This causes less of a strain when you turn the amp on and off between sets.

Here's the link:

http://www.rickonslow.com/FAQ-TubeAmplifiers-1-13.html#q9

 

[myqqy]

Great information in this thread, and I agree with the advice to have extra tubes around to swap out when noise occurs. I'm a little OCD now with checking standby and off modes on my mesas..

 

[EL84]

:lol: This is Rick Onslow. I know this tech, he's living in Montreal. I only realized it when i looked up. That's weird i just googled the question...


Q: I left my amp on (not on standby) overnight. What kind of damage this will do to my amp? (Morgan H)

Leaving your amp on continously is not a problem if there is adequate ventilation. It is more damaging to turn the amp on and off frequently than it is to leave it on. Power tubes are like light bulbs and their lifetime is rated in hours. This rating decreases the more they are switched on and off. Radio stations still use very high power tubes to transmit their signal and they leave them on 24 hours a day.

It's a question of metal fatigue caused by constantly changing the temperature of the elements in the tube. As they expand and contract the metal weakens causing the tube to become microphonic and stressing the welding points that join the elements together. Eventually the element can break off or cause a short. When the amp is on standby there is no plate current but the heater filament is still on in order to keep the tubes warm. This causes less of a strain when you turn the amp on and off between sets.

Here's the link:

http://www.rickonslow.com/FAQ-TubeAmplifiers-1-13.html#q9

Exactly...Leaving my amp on all the time came from my radio days. In radio you never turn stuff off....mixing desks, cart and reel to reel machines...it all runs 24/7. A tube on stand-by all the time is a happy tube.