Power Amp in on Marshall 2204?

[JustMike]

 I tried it just before the MV and it works, but not enough gain. So if I back it up to pin 2 on V2, am I not in the tone stack now? I want to be able to plug in an external preamp to the Marshall power stage.
 Thanks!

[stingray_65]

Mike,

I can't give much insight to your problem, but I do know that the guys here will be able to help you with a bit more info.

I do know that impedance matching is important to this sort of thing, so maybe if you tel us what kind of pre amp you;re using would be helpfull.

Ray

[JustMike]

 I've tried it with a Boss GT-6 and a B.K. Butler Blue Tube. The sound is clean, but not 50w Marshall loud.

[sluckey]

I tried it just before the MV and it works, but not enough gain.

That's the best place to connect an external preamp input. You'll need to provide the desired gain with your external preamp.

So if I back it up to pin 2 on V2, am I not in the tone stack now?

yes

[Tone Junkie]

I would say look in the schematic archive and find how marshall did it with there stand alone power amps and copy that.
Bill

[Boots Deville]

I just looked up the GT-6 to see what kind of outputs it has.  The nominal output level of the "output" is listed as 0dB and for the "send" it's -10dB.  If you're using the "Send" for some reason, try the "output".

Then I noticed the info I've attached - did you try those different output modes?

Sometimes stand-alone power amps have an input stage before the PI.  Refer to the AX84 link for an example.  That may be what you need here.

http://www.ax84.com/static/corepoweramps/Standalone_PP/AX84_Standalone_PP_Poweramp_Schematic.pdf