#1
Okay, so guitars have their woods/body shape, their hardware and pickups, and strings generally to give them their 'guitar voice'. (don't forget the name painted onto the headstock! ). Only two of these cannot be replaced on the guitar, their wood and shape.

So, what items in tube amps give them their tone? Just the straight amp. I know they have their speaker(s in some cases), cabs in stack situations, their tube choice, and thats about it. Can someone enlighten me?

Like, explain to me the difference between a JCM900 and a Fender Twin Reverb in their electronics, and not their end tone.
#2
In very, very, very rough order of importance:
Overall topography of the circuit (the "style" of the amp, marshall/fender etc)
Output transformer
Preamp (tone stack and gain stages vis a vis power supply)
Power amp (power tubes via bias supply)
Power supply (rectifier and filter caps)
Power transformer

The thing with amps is, it's not really modular in the way guitars are. You can swap pickups in a guitar, but you can't just pull out parts of an amp circuit and replace them. Actually, you can, but the parts are much more interactive and complex, such that it's not something the average guitar player can just sit down and do in an hour like almost anything you'd do to a guitar.

As far as your question about the difference between a JCM and a twin reverb:
Unfortunately, I think that in order to understand the answer to that question, you have to be able to answer the question. The schematics to both amps are readily available; take a look at each one and you'll see that there are a lot of differences before you even get to component brands and whatnot.
#3
Quote by Roc8995
In very, very, very rough order of importance:
Overall topography of the circuit (the "style" of the amp, marshall/fender etc)
Output transformer
Preamp (tone stack and gain stages vis a vis power supply)
Power amp (power tubes via bias supply)
Power supply (rectifier and filter caps)
Power transformer

The thing with amps is, it's not really modular in the way guitars are. You can swap pickups in a guitar, but you can't just pull out parts of an amp circuit and replace them. Actually, you can, but the parts are much more interactive and complex, such that it's not something the average guitar player can just sit down and do in an hour like almost anything you'd do to a guitar.

mind = blown
#4
Think of it this way... take a Fender '59 bassman, class A/B amp, 30-40 watts

Make the following changes...

Shared cathode on the Bassman to split cathode
Tube rectifier to solid state rectifier
Higher filtering in the power supply
New output transformer
6L6s to EL34s

Bam, you now have something that very much resembles a 50 watt Marshall plexi.
#5
Quote by Roc8995
In very, very, very rough order of importance:
Overall topography of the circuit (the "style" of the amp, marshall/fender etc)
Output transformer
Preamp (tone stack and gain stages vis a vis power supply)
Power amp (power tubes via bias supply)
Power supply (rectifier and filter caps)
Power transformer

The thing with amps is, it's not really modular in the way guitars are. You can swap pickups in a guitar, but you can't just pull out parts of an amp circuit and replace them. Actually, you can, but the parts are much more interactive and complex, such that it's not something the average guitar player can just sit down and do in an hour like almost anything you'd do to a guitar.

As far as your question about the difference between a JCM and a twin reverb:
Unfortunately, I think that in order to understand the answer to that question, you have to be able to answer the question. The schematics to both amps are readily available; take a look at each one and you'll see that there are a lot of differences before you even get to component brands and whatnot.


Alright, thanks. I have a decent hand in electronics and wanted to know how amps got their voicing and figured the circuits couldn't have TOO much to do with it, more about different pieces of the puzzle like tubes.

If I swapped my pre-amp tubes, they would sound more different on an amp than swapping power amp tubes, but these tubes put to a completely different amp (not like swapping a bassman to a plexi or a HRD to a Deville which have the same basic circuit) would probably induce a larger difference in tone?
#6
Quote by lifesuckstomuch
mind = blown

That's not even getting into it. Those are the 'lego' style blocks. Ground-up amp building is more akin to starting with a vat of petroleum and making your own damn legos.

Here's a picture I like to show people:

That's the inside of a Mark IV dual rectifier. Not exactly like the inside of your guitar, yes?
#7
That seems fairly...easy to understand to me?

I still don't know how electronics give a different tone. Pickups are one thing since they are different magnets. I can understand knobs/tubes because knobs have a control to them (higher treble, less treble being blocked by the circuit) and tubes because they are like light bulbs, in the fact that they can heat up to different heats and provide more current/less current all that fun stuff.
#8
Quote by manhangi
Alright, thanks. I have a decent hand in electronics and wanted to know how amps got their voicing and figured the circuits couldn't have TOO much to do with it, more about different pieces of the puzzle like tubes.

If I swapped my pre-amp tubes, they would sound more different on an amp than swapping power amp tubes, but these tubes put to a completely different amp (not like swapping a bassman to a plexi or a HRD to a Deville which have the same basic circuit) would probably induce a larger difference in tone?

Well, no. The circuit has WAY more to do with the tone than the tubes. Those tubes have to be powered- you need a bias supply. That affects tone. Then the signal going through them has to be regulated- you need a cathode circuit. That effects tone. You have to have a volume knob. That effects tone.

The amp needs to be built 'around' the tubes, because they're particular about plate voltages and such, but they're really a much smaller part of the equation than most people realize.

I'm not quite sure what you're getting at with the second question, but think of it this way: you can take all the tubes out of a fender twin reverb and put them into a dual rectifier and vice versa and the amps will sound just as they did before.