Question for an amp w/o a "Standby"

Discussion in 'Amps and Cabs' started by edward, Mar 21, 2008.

  1. edward

    edward Supporting Member

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    Hey all,

    Just a question regarding an amp w/o a standby switch (a Fender PRII for reference):

    In a session break, is it better to power off, or should I leave it on for the 30-45 minutes I won't be playing through it? And if I leave it on, does zeroing the master vol help anything? Thanks!

    Edward
     
  2. soldano16

    soldano16 Member

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    I was told lowering the volume does nothing.
     
  3. John Ward

    John Ward Member

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    Just turn it off when you take a break. PRII have a ground switch on the back and a tech could rewire that switch in about 10 minutes so you would have a standby.
     
  4. bonchie123

    bonchie123 Supporting Member

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    This is totally my opinion, but I don't think it matters. While I don't doubt the standby switch is useful on amps and may save some tube life when powering up, in the overall scheme of things its not a big deal and whether you use it or not, or if your amp has one or not, you'll be fine.
     
  5. trisonic

    trisonic Member

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    When I was growing up all my Dad's gear was tube powered - I don't recall a Standby switch on a Radio, Radiogram, TV etc.
    You know what I mean....

    Best, Pete.
     
  6. scottlaned

    scottlaned Member

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    I have no standby switch, and I leave the master all the way down when I'm taking short breaks all the time. If its going to be 30 minutes, I'll turn it off though.
     
  7. justonwo

    justonwo Member

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    I think the idea is that tube rectified amps have a short delay before the rectifier heats up. That means the power and preamp tubes aren't hit with any significant voltage on the plates for a short while. This delay allows the filaments to heat up. The other argument I hear is that small amps without a standby typically have lower plate voltages that make cathode stripping less likely.

    Amps with diodes will hit the plates with full voltage as soon as they are turned on . . . unless there's a standby.

    I know there's some debate out there about whether cathode stripping is a real phenomenon in guitar amps, but this is the most common argument I've heard. (Of course, there are many tube rectified amps with standbys, too). Since I haven't read any rigorous studies on the subject and haven't done any tests myself, I can't say for sure.

    I will say that my Champ seems to do ok.
     
  8. mcdes

    mcdes Member of no importance

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    im thinking about the same question at the moment, i got a heritage ac30 with no standby and no master volume, at the moment i leave it on, but am worried about tube life.

    because its mic'd up, it has slight pop when turned off sometimes, which i dont want so i just leave on and turn volume pedal off.

    more thoughts on this topic would be nice.
     
  9. edward

    edward Supporting Member

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    OK, so if I leave it on, unplayed of course, does this wear the tubes just as if I *were* playing it? Or is power on without play/volume not really taxing the tubes as it would if I were really playing?

    Keep in mind that I am not really after maximum tube life, but I do wish to avoid unnecessary wear if I can avoid it. Thanks guys!!

    Edward
     
  10. MartinC

    MartinC Member

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  11. StompBoxBlues

    StompBoxBlues Member

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    It's all opinions. What isn't "opinion" is the physical characteristics, facts. It is a fact that turning off and on again will cause the hot tubes to cool down, and heat up again when on next. How important this is is debateably.

    So, my opinion, from years of experience with electronics is, you want to avoid temperature swings. Most often (not just musical instuments) fauilure occurs on things when turned off then on again. Wear and tear from heating (and they get HOT!) and cooling down to me would mean, keep it on when taking a break. Another thing, MANY folks here mention that they think a tube gets "optimal" after like 20 minutes playing, which means, if you think that, that the first 20 minutes after a break your sound isn't optimal. As far as master volume, I think it works just as well to turn guitar (or volume pedal if you have one, or turn on tuner if it mutes) vol off.

    On the "turn it off when taking a break" I can only think of electricity expenses (which presumably you aren't paying) as being on the plus side. What other benefits? I think tube wear and tear is worse with changes in temperature.
     
  12. edward

    edward Supporting Member

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    Thanks all. Keeping it "on" seems to be the simplest thing to do, especially absent any real facts to deter me from doing otherwise. Appreciate the feedback, guys. :)

    Edward
     
  13. MartinC

    MartinC Member

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    Yep ... I don't think that's going to do any harm.
     
  14. trisonic

    trisonic Member

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    Just like to add to my earlier post on Domestic Appliances from the '50's and '60's.
    Valves were plentiful and well made back then - I can't remember biasing an old Marshall when swapping tubes - but then I was using real Mullard valves.....I'm sure their tolerances were much, much tighter back then.

    Probably the right answer is this: If the amp designer wants you to use the Standby in a certain way, follow their instructions - I have a large modern 100 watt amp and tend to let it warm up for at least half an hour on Standby before use, if I can - the designer loves me! If your amp doesn't have a Standby switch don't worry about it either.

    Certain old Marshalls sizzled loudly on stage even when on Standby - any other people of my age remember this and how frightening this was when you strolled across the stage and there were maybe six stacks doing it? I'm not sure in my memory whether this was specific to certain models.

    Best, Pete.
     
  15. fullerplast

    fullerplast Senior Member

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    Absolutely! Often, the most stressful thing an amp (and the components) goes through is power up and standby on. That's when the large voltages arc across switches and when the largest inrush currents occur, larger than at any other that the amp sees. Slo-Blow fuses accomodate that initial current, otherwise they would often blow. If you have a standby switch, that's when the switch (that is not spec'd for the high DC rating) will arc and that's when the filter caps get hit the hardest. So just like a light bulb, if something is going to fail, it will most often happen on power up. Just keep the amp on....it will almost always be easier on the amp. Possible exceptions are amps that idle very hot and do not have adequate cooling.
     

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