Maxing amps- how long is ok?

[Sea Chief]

Hi- assuming its relatively similar in terms of wear/ 'push' on a set of 6v6's (in my case/ a Dlx Rev) having the gtr vol low or high WITH the amp max vol 10.. I think its generally same wear..

& if I want to keep the amp simply flat-out, & just use the gtr vol (bc I believe yous gets the best tonal results like so) mostly in my case gtr vol 2-5 say.. how long is it safe, or usual say, to keep the amp at max?

With no experience of using an amp dimed (Ive always tentatively put it at 3 or 4, only occasionally going into OD at 7 say) I have no knowledge of the useability of an amp in this max state, & I guess in particular Q is the set of power tubes/ how long they might last, &/or how happy they are being pushed like so.

Thanks, SC

[nosaj]

Hi- assuming its relatively similar in terms of wear/ 'push' on a set of 6v6's (in my case/ a Dlx Rev) having the gtr vol low or high WITH the amp max vol 10.. I think its generally same wear..

& if I want to keep the amp simply flat-out, & just use the gtr vol (bc I believe yous gets the best tonal results like so) mostly in my case gtr vol 2-5 say.. how long is it safe, or usual say, to keep the amp at max?

With no experience of using an amp dimed (Ive always tentatively put it at 3 or 4, only occasionally going into OD at 7 say) I have no knowledge of the useability of an amp in this max state, & I guess in particular Q is the set of power tubes/ how long they might last, &/or how happy they are being pushed like so.

Thanks, SC

Do you drive your car in first gear with the accelerator floored? Just set the amp and guitar where you like it. All things will wear if you use them, quit worrying so much an get some experience with it, if it breaks you know people still will help you here.

nosaj

[Jazz P Bass]

Not too sure what you are on about here.

IF the amp is set to max & the guitar is set to 3-4, then the amp is not maxed now is it?

If you are in doubt, measure the ac reading at the speaker terminal.
Power (wattage)= that voltage/ squared, divided by the speaker resistance.

Power amplifiers are typically run in this fashion. (volume control maxed)
The mixer board then controls the power.

[Sea Chief]

Not too sure what you are on about here.

IF the amp is set to max & the guitar is set to 3-4, then the amp is not maxed now is it?

Hi JP. Well, this is my Q: I don't know. I could say yes the tubes are being pushed to their max even with the gtr not plugged in bc its humming away more (physical signs its working hard), the tubes are producing more heat etc. If I left it like this, w'out the gtr plugged in as a good eg, & I leave it like so.. I assume this is much wprse for the amp than if I left it idle with its vol on 1. ?. I dont know.

I've also been told by an absolute tube amp tech pro, in reply to the same Q/ same eg being amp @ max, that.. "Yes it’s still being pushed, but not as much as when the gtr vol. on MAX": which does leave much room to ponder, and does too rather counter what you've said.

[Sea Chief]

Do you drive your car in first gear with the accelerator floored? Just set the amp and guitar where you like it. All things will wear if you use them, quit worrying so much an get some experience with it, if it breaks you know people still will help you here.

nosaj

Im trying to establish what are safe amp operating perameters, in general.

If I hear time & time again about power tubes failing, and I hear horror stories about failing ytubes taking out resistors or worse an OT, & I know that pushing the amp @ max encourages the tubes' life to drop.. Im simply asking: by how much (general ballpark)? & what are safe limits. Thats all. If my Q angers or annoys you (as it seems), please just leave replies to s'one else?

[tedmich]

Supposedly EVH does a test where he dimes the entire amp, hits the strings and then leaves the guitar for several hours/days. If its still ringing at full chat when he returns is ok for the road.

Gotta keep the tubes coming but every well designed amp should be able to be run full on all the time.

[pdf64]

I could say yes the tubes are being pushed to their max even with the gtr not plugged in bc its humming away more (physical signs its working hard), the tubes are producing more heat etc. If I left it like this, w'out the gtr plugged in as a good eg, & I leave it like so.. I assume this is much wprse for the amp than if I left it idle with its vol on 1. ?

Assuming that the bias is suitable and the amp is not oscillating, the power amp/power supply, being in class AB, responds to signal.
If there's no signal, eg no guitar plugged in, the amp should be considered to be at idle, irrespective of any control settings.
That would only change if there's a significant level of background noise, such as with a high gain channel, in which case the noise would need to be considered as signal, for the purposes of power supply current draw / power tube dissipation.
Hopefully that's not the case here!
Guitar amps need to accommodate being run flat out for prolonged periods, as that's how they're used (by me at least!).
Yes, that will stress components and weak links in the chain may fail, principally ropey power tubes. Hence it can be highly beneficial to buy power tubes from a vendor that tests and guarantees them.
The onus is then on the customer / user to test them on receipt; guarantees are wasted money, if the product is only found to be wanting after it's expired.

[elipsey]

the tubes are being pushed to their max even with the gtr not plugged in bc its humming

It hums when it's turned all the way up because it's amplifing preamp noise in the early gain stages. The power section is not working any harder than with any signal the same volume as the noise. If the power amp is loud or clipping it's working harder than idle, but that's what it's for. Also, current draw and plate dissipation are not simply functions of the number on the volume knob.

Randall Aiken states that:

It is a common misconception that maximum plate dissipation occurs at maximum power. Another common misconception is that the worst-case dissipation occurs at a full-power square wave. This is usually the source of the 50% max dissipation limit put forth by those who don't really understand what is going on. Actually, a full-power square wave results in the least plate dissipation. This is because the plate voltage and plate current are out of phase, i.e., when the plate voltage is at a maximum, the plate current is at a minimum.

Max dissipation occurs somewhere between idle and full clip. This is why we bias at less then max rated plated dissipation at idle. As long as your tubes are biased correctly, they might not last as long if you play loud, but they shouldn't just explode for no reason unless somthing else is wrong with the amp. Playing at full power stage clipping would be a good way to find that out however. If your Deluxe Reverb is a reissue, it probably has decent protection. I think Fender usually uses fuses on all PT taps, flyback diodes or MOVs to protect the OT, and other things that were never done in the old days. They know people play them loud now, and probably don't want warranty claims. Maybe someone who knows that amp better then I do could comment here.

I've also been told by an absolute tube amp tech pro, in reply to the same Q/ same eg being amp @ max, that.. "Yes it’s still being pushed, but not as much as when the gtr vol. on MAX": which does leave much room to ponder, and does too rather counter what you've said.

This doesn't make sense to me, but maybe he knows something I don't. I think it doesn't matter what number the volume knob is pointing at; what matters is the signal level. Even if you play with balls out distortion, it should still be fine unless there's something wrong with your amp. Lots of guys turn their amp up and use the volume knob on the guitar. This behavior is normal, and harmless as far as I can see.

As for the tube life, if you play loud every day you might use a couple sets of power tubes every year even if it's biased conservatively. But a set of EH 6V6's costs $20 anyway, so who cares?

[Chuck H]

SC... pdf64 has it right. Regardless of whether the other amp tech disagrees (which by what you said he actually didn't). I'll try to put it in plain speak. Not being condescending.

The additional noise you hear when the amp is cranked, but the guitar isn't being played is of no consequence, other than being noisy. That is the preamp noise you are hearing because the preamp is turned up louder. Your power amp is up full all the time whenever the amp is on. Other than the additional preamp noise it is amplifying, your power amp is under the exact same stress with the amps volume knob on zero or the guitars volume on zero and the amp volume on ten. Honest. Likewise, if you turn your amp up to ten and then turn your guitar up to where the amp is just starting to clip the power amp is doing the same work as if you had your guitar on ten and turned the amp volume up until it starts to clip. Both will sound a little different because of how these adjustments affect other things that are unrelated to how much work the power amp is doing.

I know that instinctively it seems that the amp on ten, making all that working noise, is like a balloon that's been blown up tighter. It's a reasonable and understandable perception, but it's absolutely not true. Now...

With your preamp turned up full your guitar now has more potential to drive the power amp harder than when the amp volume is on five or seven. Obviously if you can put more signal into the power amp it will work harder trying to amplify all of it. So, basically, the same amount of clipping equals the same amount of work being done by the power amp. If the amp is clipping more than usual it will be because you are pushing it harder.

Ok, so lets suppose you did want to crank the amp AND the guitar up full... How long can it stand the abuse? Well that depends on whether or not it's actual abuse. My own personal amp is designed to be cranked and clipping full time with a hot rodded circuit that drives the power tubes into a full square waveform. It hasn't failed since I built it nine years ago. Neither have two customers amps with the same circuit. I do go through more power tubes than if I weren't pushing them so hard, but the amp is built for this operation. So it isn't abuse. I can't say about your amp because I didn't design or build it. You did. If you used only spec or better parts when you built up your DR it should be fine with all the abuse you want to give it. Tubes not withstanding. If you have any under spec parts, undersized wire, questionable grounding, grounding scheme or cold solder joints in there then the amp may fail when cranked for long. It probably wouldn't be a catastrophic failure. If you have the stock reissue transformers I've heard that the PT's internal fuse may be prone to premature failure if the PT gets hot a lot. Like it might with the power tubes clipping hard. So if you want to crank it like that, just do it for awhile and feel the PT casing to see how hot it's getting. You should be able to easily keep your hand on it.

[J M Fahey]

In a nutshell: any Guitar amp (and yours certainly does) **MUST** be able to run flat out for, say, 8 hours continuously pushed by a guitar player, which is the maximum abuse it will ever see, imagine a Rock Festival with all bands sharing the same backline gear or a busy rehearsal studio, rented in consecutive 1 hour blocks by a continuous stream of Metal/Punk bands (Punk is the most dangerous of the two, go figure) on a busy Saturday afternoon/night.

Both kinds of users are staple customers for me so I'm quite certain of what I'm saying, see that kind of abuse all year long.

At home, on repairs or new designs, I simulate the same wear for test purposes (you can do the same if curious) running the full discography of AC/DC , Ramones, or similar, running amps well beyond clipping.

Why that choice?
1) that simple, crude Music stands being very distorted yet not annoying and still somewhat comprehensible (you can still make ou the words).
2) is WAY more bearable than a 1kHz tone, which sometimes makes neighbours call the Police or at least kick my door.
3) has lows/mids/highjs , a much more realistic test signal.
In fact somebody tested modern Music with analytic software (how much of each frequency is statistically present in a full song, and at what level) and found it's equivalent to "soft clipped pink noise" , not kidding, and I tend to agree.

If the amp does NOT stand that, as in old Twins, which blew their speakers if dimed, then by that definition they are not capable of continuous Rock use.

Of course, the early Fenders were meant for Country players, and later for "clean" early Rockers so in that context they were usable.

It was the smoky Club Chicago Blues players who started to incorporate the distorted guitar sound by overdriving their inadequate Fender Tweeds trying to reach the back of crowded places with no PA ... the rest is History.

[Justin Thomas]

My only thing is, bullet- or ijjit-proofing an amp so much that it won't explode under any circumstances will take out a lot of the charm of running a raggedy dined amp... For those of us who prefer the Crazy Horse Method of getting distortion, anyway. Ultimately, you just bite the bullet, crank it, and pray for the best...

My personal test is to just start at one, wind it up to ten over an hour, then keep it there for an hour, all while playing guitar through it, of course. If the speakers and trannies are still alive, <AND> the distortion sounds good, I consider it working. Nobody ever lets me play over 5, anyway. But that doesn't stop me in my bedroom.

Justin

[pdf64]

...So if you want to crank it like that, just do it for awhile and feel the PT casing to see how hot it's getting. You should be able to easily keep your hand on it.

I find that 'upside down' amps (as per regular BF Fenders) may tend to run a bit hotter than that; I really wouldn't want to keep my hand on the PT (or speaker magnet) of my build for long, immediately following a good session.

I think that Aiken's analysis, by convention and necessity, assumes a resistive load and standard wave forms.
However, the rather reactive nature of speakers, and highish output impedance of tube guitar amps, will mess with the wave shapes and complicate things.
So the way things actually pan out may differ to the model.

[Sea Chief]

Right ok I seem to have opened a whole arena of thought/ explanation on this, I must try & distill to the essence or I'm overwhelmed.

With your preamp turned up full your guitar now has more potential to drive the power amp harder than when the amp volume is on five or seven. Obviously if you can put more signal into the power amp it will work harder trying to amplify all of it. So, basically, the same amount of clipping equals the same amount of work being done by the power amp. If the amp is clipping more than usual it will be because you are pushing it harder.

Ok this addresses the input signal from the gtr. (is the word "clipping" then associated solely with this gtr input level?). But Im still not getting whether an amp is working harder if its on 10 or if its on 5. (Does it depend entirely/ solely on the gtr input??).

Forget the gtr vol then/ assume on 10 if it complicates things for the purposes of what Im fundamentally trying to establish with the amp (& its stress on the power tubes chiefly). Once I can establish this, then I can add into the equation the gtr vol, and whether any increace here adds load or stress to the power tubes.

Can someone condense the info here for me? Im drowning in info I cant understand 3/4 of it whatsoever. I really need as simple as possible: yes it works harder, no its the same. If gtr vol X: it works more/ the same.. or

1) does the amp work harder for eg at vol 10 than vol 5 [with gtr max]?
2) does the amp work harder for eg at vol 10 than vol 5 [with gtr 5]?

Thx SC

[Dave H]

Can someone condense the info here for me? Im drowning in info I cant understand 3/4 of it whatsoever. I really need as simple as possible: yes it works harder, no its the same. If gtr vol X: it works more/ the same.. or

1) does the amp work harder for eg at vol 10 than vol 5 [with gtr max]?
2) does the amp work harder for eg at vol 10 than vol 5 [with gtr 5]?

Thx SC

Forget about the position of the volume controls. It is irrelevant. All that matters is how loud it is. The louder it's being played the harder it's working.

[Jazz P Bass]

SC
After being acussed of getting snitty, I will try to clear this up for you.

#1: put a meter on your speaker , set it to read Volts ac.

Then you will have all of your answers.

Amp on 10, guitar on 10: probably the amp is maxed.(measure it)
Any other condition will result in less output power.

The 'works harder" part is all relative to the output of the amp.