Pre amp Tubes, V1, V2, V3.... please enlight'n me

[murkat]

Hey guys, please explain to me the "what does it do for the amp"...
V1, and V2, and V3 so i can better understand my amps a little more.
I do not want to assume anymore and wish to be informed. Amps in question, my marshall 2204 and my concorde.
what I know, or at least i think I assume as V1 is the drive, V2 is... I dont know, V3 is the phaze inverter (?) I just would like to know each purpose of and what they do individually and then collectiveley. this way I can place tubes in what V and know what the hell I'm doing....
thamks in advance1
Jay

[Bob-I]

The tubes you're asking about are dual triodes, 2 stages. On the 2204 V1a and V1b are both gain stages, V1b has a gain control on it's input. V2a is a gain stage, V2b is a cathode follower that drives the tone controls. V3 is the phase invertor, aka phase splitter. It divides the signal into 2 halves for the power amp.

I don't know the Concord.

[Fischerman]

To add to what Bob wrote...V1 on your Marshall is the first tube your guitar signal sees and since everything will be amplified so much you want this tube to be low microphonics and low noise. The signal at, say V3 - the phase inverter; is already pretty big and is not further amplified nearly as much as the input signal so you can often get away with a slightly microphonic/noisy tube and not have it be a problem at all.

Also, generally speaking V1 will have the greatest impact on tone. Again, because the signal is further amplified so much as it goes through the amp...the earliest triodes have more effect than the later ones. Many people only use their NOS tubes in V1 and use new production everywhere else because the tonal difference after V1 is often negligible.

Also, the Concorde is actually sort of similar to your 2203 except that the tone stack is in a different spot. Other than that it's same as far as gain stage/cathode followers/phase inverter goes.
Both amps go: Input-gain stage-volume-gain stage-gain stage-cathode follower-PI. The Marshall has the tone stack after the cathode follower while the Concorde has the tone stack after the first gain stage and before the volume control. And the Marshall has a Master Volume just before the PI (after the tone stack).

[murkat]

Thanks guys for the explanations in layman's terms.
Mucho Thanks!