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spooki

powering up and down a tube amp

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Hello again: Happy to say I have all my gear in good working order now. Pedals chained to desire, etc. and my two amps in stereo. I am also very happy to say that I am improving much faster now with the never ending learning curve. I guess you could say I'm past the curve of frustration and can't wait to dive in again. It does get easier and more enjoyable.

 

It's been a fun ride again to journey the trip of picking up the guitar after 30 so years.

 

Here is my question. Both my amps are all tube. One of age with no standby switch, the newer one with. Because of my back problems, sometimes I only get a set in of practice for 15-20 minutes tops. I worry about powering up and down and the effects of doing so.

 

Not a big deal on working days. But on weekends this might happen 5-6 times a day if not more. If and when I'm done for a rest on the back, (after 20 minutes of playing). I usually leave them on for another half hour tops. Should I just be leaving them on during the weekends knowing well that I will dive back in an hour or so later? I so envy you guys that can practice and play for hours on end.

 

Strapping up and standing is a huge help. But I'm back on the bicycle of learning once again and still need to see where I'm playing for now. Hence the hunched over back while sitting.

 

So do I power up and down, or let em' sit? Thanks again to all.

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Hello again: Happy to say I have all my gear in good working order now. Pedals chained to desire, etc. and my two amps in stereo. I am also very happy to say that I am improving much faster now with the never ending learning curve. I guess you could say I'm past the curve of frustration and can't wait to dive in again. It does get easier and more enjoyable.

 

It's been a fun ride again to journey the trip of picking up the guitar after 30 so years.

 

Here is my question. Both my amps are all tube. One of age with no standby switch, the newer one with. Because of my back problems, sometimes I only get a set in of practice for 15-20 minutes tops. I worry about powering up and down and the effects of doing so.

 

Not a big deal on working days. But on weekends this might happen 5-6 times a day if not more. If and when I'm done for a rest on the back, (after 20 minutes of playing). I usually leave them on for another half hour tops. Should I just be leaving them on during the weekends knowing well that I will dive back in an hour or so later? I so envy you guys that can practice and play for hours on end.

 

Strapping up and standing is a huge help. But I'm back on the bicycle of learning once again and still need to see where I'm playing for now. Hence the hunched over back while sitting.

 

So do I power up and down, or let em' sit? Thanks again to all.

 

Hope I can help here,and I hope I don't tell you wrong,either,but anyway,...on an amp with a standby switch if you're going to play for about fifteen to twenty minutes a stretch and stop to take a break,I would just put the amp on "standby". On an amp without a "standby" switch(Fender Blues Jr,for example,...I know,I had one before),I would just leave it on and turn the volume way down,...at least that's how I done it. I do this with my amateur radio equipment,even though it's a solid state modern radio,...if I'm going to take a short break,I just leave the rig on and turn the volume down,and when I am ready to start up again,turn up the volume and continue. But,...if you're going to be away from it for a much longer period of time,say two or more hours,I would go ahead and power down! It all depends on how long of a break you take between practice sessions,..if they're short breaks,leave it on and put it on "standby"if equipped with standby switch,...if no standby switch,leave it on and turn your volume down. I could be wrong here,but I would think that powering up and down a lot does more harm than just leaving it on. As with a light bulb,..constantly heating and cooling the filaments in a tube by powering up and down a lot shortens the life of the tubes. When you know for sure that you are completely done for the day,by all means,power down all the way. What make and model are your amps,by the way?

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I think DEWEY's right.

 

I would day, the thing to remember is tubes wear eventually, so what you do or not do isn't the end of the world because really it only means replacing tubes a little sooner than later.

 

Powering up and down does cause wear, as what makes a tube wear is really the metal parts inside...so heat is one thing, heating and cooling can be just as hard on them.

 

Another argument for leaving them on, is that it really takes a few minutes for things to warm up and settle in, to get all the voltages stable and where they want to be. I'd say usually at least 5 minutes, and maybe 20 minutes to be completely stable.

 

Not to mention, when things are "warm", they tend to sound better, even SS do.

 

Either way, I wouldn't worry about it. If anything, having them on and waiting to go is more handy than having to wait, and less where I think than turning them on and playing them cold...especially on the hour.

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Back in the day of the dinosaur, when every amplified device was tubes, we didn't think about such things. Even tube radios in cars were reliable, despite vibration/shock, temperature extremes and frequent on/off cycles. I don't remember a single failure of any of our tube guitar amps, either. TV tubes went on the fritz occasionally, but overall were quite reliable, expecially considering how much a TV is used.

 

Wondering if the common internet-reported precautions were stated by manufacturers, I checked out owner's manuals from Fender, Marshall and Egnater. Nothing of the sort, except for recommendations to warm up the amp for 1-2 (not 10-15) minutes before hitting the standby switch.

 

Sure, it doesn't hurt to be cautious, but I don't think these things are as fragile as some might be led to believe by the ubiquitous internet noise.

I tend to agree, but I don't know of the "internet noise" you are referring to. I don't recall reading or hearing the amp will blow up if you don't do a particular procedeure, but then again (if you can't tell), I mostly spend my time playing on the internet here.

 

I would say though, I think it's rare if you haven't experienced a tube failure, especially if you have been playing long enough to have had tube car radios and tube televisions. Personally, I would say that ALMOST every amp that I have played or used regularly or a lot has had a failure of some sort, and it's usually a tube. Although, I wouldn't exactly call it an amp failure, but rather a tube failure. I don't blame it on anything though, except perhaps my habit of running an amp into the ground before regular replacement, or not using the best of tubes.

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I remember tube type TV sets quite well,...but not tube type car radios since they were just a little before my time. I would say that the most common failure was a tube in those old sets. If you have a tube amp for a very,very long time(years perhaps),how often would you end up replacing tubes in a guitar amp? If you used a good quality tube,about how long would they go before replacement? I didn't have my first Blues Jr.amp from years ago long enough to find out,so that is why I am asking. If you didn't push the amp real hard,I bet they lasted a LOT longer!

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I remember tube type TV sets quite well,...but not tube type car radios since they were just a little before my time. I would say that the most common failure was a tube in those old sets. If you have a tube amp for a very,very long time(years perhaps),how often would you end up replacing tubes in a guitar amp? If you used a good quality tube,about how long would they go before replacement? I didn't have my first Blues Jr.amp from years ago long enough to find out,so that is why I am asking. If you didn't push the amp real hard,I bet they lasted a LOT longer!

Gee, that's a good question. I certainly don't know.

 

I can say this: those Telefunken 'smooth plate' 12AX7's last a long, LONG time. I had one particular amp where I put those in, and they lasted through FOUR power tube changes! Also, I had a tube stereo with a pre that used one 12ax7 for each side, and the Tele's it came with had as much hours roughly as 2 other tube changes where I wore out the tubes, but they were still going strong.

 

With my Deluxe Reverb's, I tended to change power tubes because it would start sounding crappy. But, whether I has replaced the pre-tubes myself, or the stock RCA's or GE's, they seemed to go eventually. Pretty much any amp I had.

 

I have noticed, that any amp I had or came across (I only actually have one) with EL-84's, those amps usually beat the crap out of the EL-84's. And, also going though used tube bins, any EL-84's I would come across are beat to hell.

 

I am not a tech, but I am aware that a lot of modern stereo equipment that's tube are made closer to the limits on how they run the tubes than older ones, or rather, it's more variable that some are and some aren't. I also know that when it comes to guitar amps, they are running tubes much closer to the tube max and sometimes over, than compared to older stuff like old radios and TV's.

 

And also, depending on how something is wired and biased, it could cause some tubes to wear faster in some areas at idle than when putting signal through it. I don't know if any guitar amps are this way, but I had a set of Quicksilver stereo amps that cooled down a bit when playing music.

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Hey guys, good stuff and have enjoyed the education and ideas. I must thank Dewey for bringing this alive. It sat dormant for almost a month and now is alive. Sorry to say that I finally went to another site to get some answers. Thanks again and never to late too broaden the span of Q&A's.

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Hi, I've just checked the schematics for your amps and neither of them will really benefit from the use of a standby switch. In fact leaving an amp in standby mode for too long is quite bad for the valves, google 'cathode poisoning'. NOS valves are often less susceptible to this due to purer cathode material, but if there is a chance you could forget that the amp is on then don't risk it. Several hours of standby will reduce the gain and lifespan of your valves.

 

Standby switches are only useful if your amp has a DC coupled gain stage such as a cathode follower. Even then, there is a much better alternative to a standby switch - a reverse biased diode between the grid and cathode perfectly protects the valve. BTW your Univox has an AC coupled cathode follower, so no risk there.

 

Happy Rocking,

Andy

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Im going to pitch my input in here for you.

 

Im an outside broadcast engineer (3 years now) and prior to this I was a communications engineer with her majesty's finest Royal Air Force (7 years) so I've been trained in the use and maintenance of tube amplifiers and I've been working with them daily for a long time now. I currently work with TWT's - mostly 400W and 750W

 

Firstly NEVER leave a tube in standby for any length of time, this is a quick way to ruin your tubes as they 'gas up' and will degrade quickly (relatively speaking). The standby switch IS very useful when used correctly to warm up and cool down your tubes though. When you turn your Amp on you should initially have it in standby, this will allow the tubes to gently warm up with no drive to them, once the tubes have had time to warm up you should take the Amp out of standby and you can start using it.

Now its warm do not put it back into standby if you intend on using it sporadicly (keep it in 'on') - a tube amplifier likes to be left in its operating mode rather than being put back and forward into standby which brings me to my final point... Cooling down. After you have finished with your amp for sure put it back into standby and leave it like this until it has cooled down. Once it has cooled down you can turn it off. Tubes are made of glass and glass does not like rapid changes of temperature so if you follow what I have said you will have many years of use from your Amp!

 

As for warm up/cool down times this will depend on a few different factors. The rating of your Amp, how hard you are driving it (volume played at) and ambient temperature. As a guide I would say 5 mins to warm up and a min cool down of 10 mins.

 

I hope that helps you mate, any questions fire away!

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Think of your tubes as incandescent light bulbs. Turn em on leave em on for long periods they last longer that on and off in short periods of time. So if I fire my amp up and give it a few minutes in standby, if I know I'm going to be playing sporadically through the day such as you do, I'll leave it on until I know I'm done for the days. I just turn the volume all the way down. If I know I'm done playing for the day I'll put it in standby for around 15 minutes before power down. My little fender champ with no standby gets the same treatment. Just volume down and let it cook.

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...

Firstly NEVER leave a tube in standby for any length of time, this is a quick way to ruin your tubes as they 'gas up' and will degrade quickly (relatively speaking). ...

+++1

 

People having tubes for sale may tell you the contrary, but this isn't correct. With the heaters on, tubes should be run with an appropriate plate current, and the latter is interrupted using the standby switch. The cathodes may degrade until the tube will be killed by turning the standby switch on.

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