Hi everyone,
I have a question about tube saturation. We know that tube amps sound best when cranked but how high is cranked? In other words, at what volume does tube saturation occur? Does the volume have to be maxed all the way or is half-way or three-quarters high good enough?
Thanks and I hope this question is not too silly.

It varies, on my amp, I'd notice it increase right from 2 all the way to 10.

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my 5150 that i had, at about 3.5 and i had a great sat. tone

So not even half way cranked?

This is actually a good question because what is exactly cranked? This too i've wondered for awhile. I used to play my Bv300 in my room occasionally on half (5/10 i guess) and it sounded pretty good.

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Dude, 3.5-4 on the Post Gain on that amp is pretty fucking loud.

I've never turned my amp up past 5. The 150 or the 300. The 300 was shaking the entire house so i think that is probably loud enough.

3ish is when it starts to get too loud for normal everyday fucking around. Although on a day when i want to rock out (in my apartment) i'll put it around 3 or 4.

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To get the powertubes really cooking you REALLY have to push that master volume, even wallquaking volumes aren't gonna produce any powertube distortion, only very seriously high levels will do that. I have an Engl Fireball and have pushed it to 11 o clock(FUCKIN LOUD) and didn't feel any powertube breakup, I only tried it at around 2-3 o clock(got neighbor complaints from 3 stories below me) and it was a fuckin Sunday at 2 pm) and I STILL didn't get any powertube breakup, you need to push it much more. (funniest thing is that I bullshited them into thinking I was an audio engineer student and I had to finish my amplifier-project for college, the suckers fell for it but I only played for a few more minutes at 1 o clock. )

Since everyone here has high gain amps noone notices that 99% of their sound is coming from their preamp, not poweramp tubes. The real way to hear how loud you have to push an amp to get powertube breakup:

Go try a Marshall JMP or any other 70's or early 80's rock amp, and see if you can crank it til you can get acceptable metal sounds, if the store owner lets you! True powertube breakup is extremely difficult to achieve, most apartment dwellers with 50W tube amps like me aren't going to be experiencing it at home anytime soon.

Or even easier, try an Epiphone valve junior, put it the volume up nearly on full to get some actual distorted sounds, that's how far you have to dime the volume to get powertube breakup.

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Thanks for that valuable information, guys! As for me, I'll stick with my low wattage tube Marshall for now. That way I can crank it and get more power out of it. I'd rather not get a high wattage stack and use an attenuator. I'm "sceptical" of those things, even though I must admit I never used one! But I read they weaken the sound and make it sound "hissy" too.

Tube saturation is when you turn level up loud enough for your tone to distort.

You can saturate two sets of tubes.
Pre and Power

Signal reaches the pres first. If you distort these you wont have to turn your power up to hear an overdriven guitar.

You can turn your pres down to a suitable level and turn your power up full and it may distort depending on amp specs.

Some people like to get a combination of both.

The higher you turn up your pre the less it takes to overdrive your power.

It so sweet when you get the right amount of distortion. Its so sweet.

Thing is power tube distortion sounds extremely different from pre distortion. Pre distortion is most suitable for high gain metal, because everyone loves that compressed tone. But if you're a fan of those loose raunchy fuzzy sounds from the 60's and 70's, you really want powertube distortion then.

It's weird to see so many metalheads saying that you have to crank your amps to get good sound, when for popular metal-y tones the best results are yielded from a high gain preamp, without overdriving the poweramp.

Combining both yields spectacular results, and also spectacular sound pressure levels.

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Awesome, guys. Thanks for explaining how it works.

By the way, which current Marshall model would you say is the best for Metal? Only tube amps please.

The JVM looks really nice, it's the best Marshall so far IMO.

Yeah that new JVM looks appealing. Then there's the 2000DSL, JCM900 and 800's.

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you might want to look into using a hotplate.

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Or better yet a Weber MASS.

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I've heard a lot of good stuff about the JCM800.

So what's a hotplate and a Weber MASS? Ah, what a cabbage I am!

They're attenuators. They bog down the signal coming out of your poweramp to make it quieter, letting you push the master volume of your amp without blowing the windows out. They go in between your amp head and cab/speaker, or they can act as a dummy load for direct recording or testing purposes.

Most conventional attenuators like the Weber Load Dump, THD Hotplate, Dr. Z Airbrake, or Marshall Powerbrake use capacitors, just a bunch of small electrical components that take part of the signal from your amp and convert it into heat energy(hence they can get very hot!) so not all the power gets to the speaker cab, therefore it makes your amp quieter.

However at moderate to high attenuation levels, capacitors start to eat away the tone coming out of your amp a LOT. The Weber Mass has a real speaker motor inside, so the amp interacts with it like if it was a real speaker, so it actually vibrates inside of the mass instead of using capacitors to turn everything into heat energy, and you don't lose any of the tone. Plus they have treble adjustments, which are crucial to maintaning the integrity of the signal going into the cab.

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A huge resistor.

As a general statement, most high wattage tube amps start to run out of headroom when you have the master at around 2-3 o'clock and begin to distort. When this glorious event occurs, angels sing, women weep, and eardrums collapse onto themselves and burst into flames.

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And pregnant women have miscarriages.

I've pushed my Fireball to 2-3 o clock for a bit and didn't really notice a big difference in tone from 12 or 11 o clock or so, just massive volume difference and it was a 60W amp, you'd need to push it a bit more but there's no way I could do that at home.

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pretty much depends on the amps volume taper. some amps get louder quicker.

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The tubes themselves are another factor. KT66's will distort faster than EL34's which distort faster than E34L's/6L6's/5881's, which will distort faster than the 6V6, then 6550's, and then KT88's. These are the most commonly used power tubes in guitar amps. I listed them from least power handling to most.

Amp example would be a Marshall JCM800 2203 Master Volume amp. The only changes would be the bias resistors needed to bias the Pentode type tubes(first 5 listed) vs. the Tetrode/Beam Tetrode tubes (last 3). All other componants are identical(transformers etc...). In this case I do not believe that the 6V6 can be used in this amp do to the pin configuration 9 pins vs. 8 in all the others, so lets leave that one out for the time being.

The KT66 tube has less power handling capabilities than the EL34's which are rated for an average of about 35 watts, meaning less headroom before the tube distorts. The E34L, 6L6, and 5881(military variant of the 6L6) will handle a slightly higher output wattage rating than the EL34, but average usage is pretty much the same. They are cleaner sounding tubes though. The E34L is nothing more than an EL34 that uses 6L6 architecture. In other words, a tube that sounds like an EL34, but can handle a bit more output power before distortion.

The 6550 and KT88 are pretty much identical tubes. The KT88 is the Brit version of the 6550 but was designed to handle monstrous amounts of voltage, up to 800 volts as opposed to the standard 500-600 that the 6550 is rated for. Essentially what this would mean in the example amp would be tremendous amounts of headroom, or clean signal before distortion. Either one of these two tubes would allow the user to get pretty much all of the preamp tube tone that the amp has before the power tubes even started thinking about distorting.

Using a standard Marshall amp a very simplistic rule of thumb would be like this:
KT66 = classic rock tone from 60's and 70's but at lowered power output
EL34 = classic rock/metal tone. You have heard this on pretty much every rock/metal album from the mid 60's through today.
E34L/6L6/5881 = Classic to somewhat more modern tone being a bit cleaner(not too much). The 6L6 is the standard power tube for Fender and Mesa amps. Newer Marshall's use these as well.
6550 = Mid 80's to today more modern tone high output volumes, more preamp signal.
KT88 = Like the 6550 but loud enough to kill the unborn children that reside in your sack.

6V6 somewhere in between the 6L6 and 6550 types. I have only seen these tubes used in older Peavey amps from the mid 70's.

Preamp tubes are rated fairly easy. 12AT7, 12AU7, 12AX7 from least hot to most hot respectively. Each kind will have its own voicing as well as gain hotness from brand to brand. I will not begin to discuss which preamp tubes are best as that is totally a personal descision to each guitarist. In my Marshalls I use NOS tubes in the preamp section. A Bugle Boy in V1, an GE-JAN in V2, and a Tesla military unbalanced (2400-1875) for V3.

I also do not match my power amp tubes. Well not totally true. I match only to achieve a 7-10 ma difference from one end of the power tube array to the other. This allows for more 3rd and 5th order distortions to come through the signal which are the organic distortions that guitarists want. The 1-2ma matching that most guys use these days work, but the amps sound stiff and more hi-fi to my ears. We play dirty guitar amps, not clean hi-fi stereo equipment.

That information is mostly wrong. The EL34 is rated at 25 watts maximum dispassion per tube (35? no.), so is the KT66. KT66 and EL34's have just about nothing in common and sound very far apart sonic-wise. Mullard or whoever had patented the pentode design the EL34 used back in the day, and RCA sure as hell didn't want to pay royalties so they made a license sharing agreement with EMI who has just come up with the Beam Power tube, and came up with the 6L6, who could deliver 19 watts. GEC [the British General Electric company - nothing to do with American GE] then decided to make an equivalent to the 6L6 and, in around 1937, produced the KT66, as a plug in replacement for the 6L6. Disassemble the type designation: Kinkless Tetrode 66. Then later came the 6L6GC. Guess what GC is for? Guitar Combo. These could deliver 30 watts each in AB1 push-pull and handle all the vibrations from the combo chassis.

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...I concur... :|

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Ugh... I came across my old thread about tube saturation.

So, say a 150W amp would have more headroom (more defined notes) than say a 50W amp, right?

That's a good thing for a tight Metal sound, I imagine? As someone said, power tube saturation would be good for the fuzzy, loose sounds of 60s and 70s Rock, if I'm not mistaken.

But then why were attenuators mentioned? As far as I know, attenuators are used when you want to achieve power tube saturation so that you can keep the volume down.

If power tube saturation is not desired then attenuators aren't needed, right? Thanks!