Gain

[Chuck H]

I think you and I are already building similar amps My current favorite design, and my personal amp, is three stages with no master volume into an LTP driving a pair of EL84's. I run the amp with the volume on eight or nine most of the time and use a "bright cap" type of circuit on my guitars volume pot so that I can get chimey cleans by turning down my guitar. As it happens, A bigger than average OT combined with a deep combo cabinet loaded with a Vintage 30 makes for a very acceptable "do all" tone that fits well into most live mixes and still has bottom and top end dynamics. Even if I had post distortion EQ (which I don't) I wouldn't really have a reason to adjust what I have now. That was an important criteria for me with this design. Sound familiar?

This amp will (at it's best) imply metal type tones. The saturation and harmonics are there. The EQ is lacking a little scoop and bottom end. As might be expected from a 2XEL84 amp in a 1X12 combo cab. But if I plug it into my deep 2X12 closed back cab I can easily do everything except the most outrageous metal tones.

I'm not driving the three stage preamp as hard as I could. At all. But there's no way I could get that uber gain sound without hammering the PI and power tubes with this amp.

I did have a Marshall that I spent a couple of years modifying (off and on) and was indeed trying to get the most out of three stages behind an EQ and a master volume. I was never able to get modern gain levels from the preamp without bad sounding side effects from driving the stages too hard. So I settled for slightly less than uber gain for the sake of tone quality. That's one reason I'm interested in any design that can do it.

[Enzo]

The language is often driven by people lacking much knowledge. I think part of the problem is that for the average player, turning up the gain results in distortion. So to him gain MEANS distortion.

Even here we do this. How many times has someone talked about increasing the bias on a tube, when they really mean increasing the current. 38ma is not the bias, -55 volts is the bias. 38ma is the idle current. But to the unwashed masses of shadetree amp techs bias and idle current are the same thing.

[Chuck H]

Just want to make something clear. Reading threads on this forum will reveal that even educated members here use the term gain in reference to distortion all the time. That doesn't mean we don't understand that there is a difference between voltage gain and distortion. We're just using the common nomenclature for the purposes of efficiency. It all started when major amp companies chose to use the word "gain" on the knob that increases distortion, but not loudness and kept the designation "volume" for the knob that increases loudness, but not distortion. We perpetuate this perversion because it's accurate to the circuits we discuss in modern guitar amplifier design. If not always technically accurate.

[Enzo]

Oh, guilty as charged here.


I find myself calling it the "gain channel" on an amp to refer to the non-clean channel. Obviously ANY channel has gain.

[loudthud]

I've never played an Orange amp. They just have little icons by the knobs. One has a fist, is that Punch? One has mountains, it that Echo? Treble and Bass clefs are self explanitory, what are some of the others?

[Enzo]

Ooh, that would be fun to invent new ones.

I foresee a kid walking in... "Yeah, I can't get enough mountain on my fist channel."


Picture of a motivational speaker for Presence.

A cold, wet puppy for tremolo.

A handful of peanut shells for cru... oh never mind

[wizard333]

the extra stage gives the freedom to dump a bit of gain here and there for tone shaping.

This is very true. I go about it a different way, using a tone stack with an extra control and unusual values to offer a wide array of tones, along with a tone shaping push/pull, and sometimes a rotary or a 3 way if I have the room.

My personal preference on an amp is that it be able to go from pretty clean to pretty distorted purely by pick control, without touching a guitar's volume, and so I require them to do that as well as very high gain for those who want that, though it isn't my personal preference. I've found most 4 and more stage designs don't do that well at all. They can be made to do it better by defanging them, adding a push/pull to switch out the stock Cks and add a little high end to compensate, but to my ear they don't get as organic as a 3 stage. IMO the crunch channel on the SLO is much more interesting than the distortion channel (trying not to say "gain channel"!) but most people probably live on the distortion channel. The crunch channel on that amp is IMO fantastic, but its a 3 stager unless you hit the effects recovery tube hard enough to drive it. What I find great about it is that it sounds like a cranked JMP at much more reasonable volumes. The other channel gets too squishy and at the higher end of the gain control, fizzy/squeely for my personal taste. I add that capability to channels I do because I know there are those people out there who, no matter how much distortion an amp has, will say "give it more", but it isn't where I personally play. I just make sure it's there and sounds right for that type of thing. If it can do a passable "One" by Metallica and "Still of the night" by Whitesnake, it passes inspection.

[trem]

RG...Enzo...everybody.....
Thanks again for the (further) reply's.
I am just a "hobby tech" (for lack of a better term) and not sure what is worse:
1. Having just an average IQ and no formal education.
or
2. The fact that I do not play guitar.

I was just "the drummer" who picked up the "ball of amp repair" and ran with it.
So WHAT do you guys get out of a "High Gain Amp".?
Sustain
Guitar volume knob and amp interaction
Dynamics
"Distortion".?
What leads you guys to build a high gain amp.?
Thank You So Much

[wizard333]

What leads you guys to build a high gain amp.?

That I know people want that. I personally don't, but then my tastes tend to be esoteric. I do know that no matter how much distortion an amp has, there are people who say it doesn't have enough. I don't know of any recordings that actually use that kind of distortion, but I know of many, many people who think that they do.

[defaced]

What leads you guys to build a high gain amp.?

For the same reason anyone plays any other amp: it fits with their genre of music.

I like metal. I play metal. Playing metal on anything but a high gain amps sounds kinda silly. The high level of distortion, saturation and compression work very well for that type of music. Sustain doesn't really figure into the mix a whole lot, mainly for the occasional lead solo that takes a step back to a more traditional rock type solo structure, but those aren't really common place. High gain amps aren't generally known for being dynamic. They tend to be quite the opposite, but there are outliers. Plenty of recordings use this level of distortion - pick up almost any modern metal album from the past 20 years.

[Steve Conner]

I remember years ago (Probably about 20 ) my brother and I used to share a guitar rig. An Ibanez Destroyer, a 100 watt high gain amp with graphic EQ and a 2x12" closed back cabinet with some random Eminence speakers.

I liked Megadeth, Metallica and Biohazard, he preferred Nirvana. I would turn the gain up all the way and set the EQ to a smiley face, to scoop out the midrange and get a good "chug" rhythm sound. He said "No, no! You're doing it wrong! Too much gain, not enough mids!" and pushed the bass sliders all the way down and the midrange and treble ones right up, to get a nasty, icepick-in-the-ear grind.

To me that sums up the difference between a "modern metal" amp and a punk or rock amp. You can get lots of gain by throwing a distortion pedal in front of a cranked old tube amp, or squeezing a 3-stage tube circuit to the max, but it'll be a punky, raw kind of gain, the sort my brother wanted.

[guitician]

I remember back in 1980 my brother asked me to make him a guitar amp with lots of gain. I was a beginning electronics tech and was up to the challenge. I scoured "Popular Electronics" for circuits until I found a high gain microphone preamp using a IC. Then added a tone control with a quad IC. This went into a 100w discrete bridge type power amp. My brother was into "Solo" guitar sounds, but "Metal" music wasn't what he was into. This amp BLASTED square waves right into the voice coil.

Fortunately the speakers could take the onslaught. I remember his friends that were into metal music being really impressed with the sounds this amp got, and I recall one of them saying "It sounds better then my Marshall". My brother bought a distortion pedal and kept the gain of the amp set low because it wasn't the tone he was after.

[loudthud]

New Icons:

Ice Pick
Frowny face to smiley face
Mud puddle
Little bells
Trash compactor
Scissors
Bull dog
Buzz saw
Three way switch: Rock, I beam, face with sun glasses and spikey hair

Post your suggestions here before Mr. Smith files a copyright

[trem]

New Icons:

Ice Pick
Frowny face to smiley face
Mud puddle
Little bells
Trash compactor
Scissors
Bull dog
Buzz saw
Three way switch: Rock, I beam, face with sun glasses and spikey hair

Post your suggestions here before Mr. Smith files a copyright

Was going to build my wife a wheelbarrow out of fancy shipping crate.....but then I was advised Randall owns the patent on the wheel.

[Steve Conner]

I'm so using these icons on my next faceplate! For the gain structure switch I'd use the rock, I-beam, and finally a pair of camo pants with a chain wallet.

One of my designs has a three-way power selector, I think for that I would have a kid's trike, a '57 Chevy and a tank.