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For the amp guys!

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Noble Member
Joined: 20 years ago
Posts: 2167
Topic starter  

Say I was invited to a friend's house and this friend happens to have one of the older 1970s Marshall amp and speaker cabs. The ones without the master volume where you had to just crank the thing. And let's just say further that this friend with the Marshall stack is in a pretty remote area and I happen to have my guitar and this friend invites me to plug in.

And after he tells me "Well, you might flush out the flock of ducks that are wintering in the lake down the other end of the road..." he nods and invites me to crank it up.

Like all the way up.

And I stand to the side of the stack so I don't disintegrate and start playing.

Now, with the way tube amps are, if I've got the volume up to 10, does that mean there's no 'headroom' - in other words, no louder I can go?

And if this is so, then is that what some amp guys talk about as 'natural compression'?

Is it as though you're at the 'ceiling' of the amp's output and every other loud thing, like strumming or picking really hard just smashes up against that ceiling and gets compressed?


Illustrious Member
Joined: 20 years ago
Posts: 7833


"A cheerful heart is good medicine."

Honorable Member
Joined: 17 years ago
Posts: 525

That sounds awesome!

"That’s what takes place when a song is written: You see something that isn’t there. Then you use your instrument to find it."
- John Frusciante

Estimable Member
Joined: 18 years ago
Posts: 205

Sounds like you had some fun. ;) re the compression stuff, yeah, you got the idea right on the nose. I think this is why some people say the sweet spot for these kinds of amps is around 6 or 7, but it all depends on your taste really, if you like it better at 10. I've never been able to do this with my gear other than through an attenuator, which doesn't really count. I really need to drag my stuff someplace remote but still with a power outlet around and give that a shot. I'm sure it's a rush.


Wes Inman
Illustrious Member
Joined: 19 years ago
Posts: 5582

With most tube amps you will hit maximum volume around 6-7. After that you just get more "saturation". This is the correct term, not distortion. It is much different than solid state distortion. Solid states tend to have a hard, almost brittle type distortion, where a tube amp distortion is very "rubbery" for lack of a better term. It is a much softer type distortion. Most people prefer this to the hard solid state distortion.

A good tube amp cranked up is very touch sensitive. You have to learn to control all those sounds. But once you get used to this type of distortion, going back to solid states is difficult. :D

In the old days, players would crank their amps up to max to get tube saturation, but then turn guitar volume down to get clean tones. When it was time to solo, or distortion for a crunch rhythm, then crank guitar volume up. To me, this is the most fun way to play. :twisted:

If you know something better than Rock and Roll, I'd like to hear it - Jerry Lee Lewis

Illustrious Member
Joined: 19 years ago
Posts: 5038

Being pedantic: In engineering-land, everything that is non-linear is distortion ... and that even includes saturation and overdrive. The music equipment makers and their marketeers have decided to reappropriate the term distortion to a more specific use, and more narrowly apply it to hard clipping, usually done in specific effects or effects pedals.

But anyway ...

Saturation is soft clipping distortion usually in the output or power stages of amplifiers, and is a more musical, gentle even order harmonic dominated distortion. When the amp gets cranked to 10 or may only 6 or 7 as Wes says, the output tubes will very easily saturate on the wide extremes of the positive and negative voltage excursions of the output waveform. What happens is the the top and bottom of the waveform get "squashed" a bit, as the amp (specifically its tubes, transformer and power supply) can no longer faithfully support reproduct at its output a larger and nearly perfectly scaled version of the input waveform. So in effect there is a compression that takes place as the amp limits the +/- voltage swing at its output. And this occurs in a soft rounding fashion in tube (and nice FET) amps. But does that mean the playing no longer has dynamics (can't get any louder)? Nope, indeed it can sound somewhat louder as one plays harder in the sense that more power does still get pushed out the the speaker. But here's the catch, that additional power will more and more appear in the harmonics of the fundamental tones -- that is the harmonic levels increase, while the fundamental stays roughly fixed at a max level (or even drops a little). And increasing saturation pushes out increased harmonic power. So the dynamics sound different, giving rise to a change in the timbre as one plays harder in saturation. As Wes says, this is the dynamic touch sensitivity of tube amps. Another way of looking at the increased loudness is this: a sine wave (undistorted, unsaturated pure fundamental tone) of a fixed peak to peak amplitude (voltage level) contains less energy than a trapezoidal (somewhat saturated) waveform of the same peak to peak amplitude; and a trapezoidal waveform contain less energy than a square (hard saturated or clipped) waveform of the same p-p amplitude. But the difference in each case is that as the shape changes from sine to trapezoidal to square, the additional energy appears in the harmonics.

-=tension & release=-

Noble Member
Joined: 20 years ago
Posts: 2337

I run most of my amps at their saturation point and I use dummyloads, attenuators, and equalizes. Yes, once you get a taste of and overdriven all tube it's rough trying to play on a solidstate amp.


Noble Member
Joined: 17 years ago
Posts: 1128

thats a fact forrok 8)

even god loves rock-n-roll

Famed Member
Joined: 16 years ago
Posts: 3709

Bet it sounded awful cool ... hope it was worth the hearing loss .... :P Just kidding. Yeah, no substitute for that sound. I believe that is the sound all overdrive / distortion units are trying to emulate.

"Work hard, rock hard, eat hard, sleep hard,
grow big, wear glasses if you need 'em."
-- The Webb Wilder Credo --