Guitar amp channel question

[Trepan]

In guitar amps, are the various 'channels' really just different hardwired preamps that are (foot)switchable, or is there something more to it?

Thanks!

[head_spaz]

What model amp are you talking about?

I have a Carvin Quad -X preamp that provides four input channels, with a stereo output.

Ch. 1 is clean.
Ch. 2 is bright.
Ch. 3 has crunch.
Ch. 4 is grunge.

Each channel has it's own gain and tone controls.

The amp can be easily configured to play anywhere from perfectly clean to filthy raunch n' nasty at the stomp of a switch.

I had an old gallien kruger practice amp that had two channels... so multiple players could plug in at the same time, but that is a rare configuration.

Hope this helps.

[Trepan]

I'm just talking in generalities. From what I can gather, it's just a bunch of preamps with the same power amp.

I'd seen an amp with 3 channels before, but never 4 I had a nice TubeWorks with 2 channels (clean/distortion) but I always just used an effects processor anyway.

[teemuk]

All those terms like "preamplifier" "channel" etc. are just a semantics issue. Define "channel" anyway. For example, take "distortion channel"; you can built one at least with two alternative methods: 1. Use two separate circuits - one of them configured to clip - or 2. Use only one circuit but alter whether it clips or not.

Basically you can have various configurations of this basic scheme: Different "channels" of the preamplfier can share gain stages, tone control circuitry etc. Different channels can be built by altering gain or frequency response by a flick of a switch - or by means of plugging into alternative inputs with different characteristics of decoupling capacitance and/or resistor divider attenuation. Then again, different channels can have a completely separate circuitry from another. Should, in latter case, those be called different "preamplifiers" or is the whole circuit before the power amplifier stage the "preamplfier".

It's all about how you like to define those terms in the first place: A semantics issue. Get over it, it isn't important. Generally speaking, the whole amplifier is just one circuit that consists of dozens of smaller circuits. In my opinion, it is impossible to say anything more definitive about it.