boosting front end of Mark2b causes restriction?

[gonzo]

if i use a clean boost in front of the amp, to boost volume and gain for solos in live applications, i encounter this:

no volume change;
much more compression and gain.

is there some kind of limiting applied in the preamp design, and if so, how do i get rid of it?

 

[LithiumZero]

Boosting the front end of an already overdriven amp will do just that, give you more saturation and compression while not really affecting volume. It just hits the first gain stage harder as if you cranked your gain knob. Boosting the front of a clean amp will result in more volume and a little more grit. Hope this helps

 

[LithiumZero]

If you want to boost an overdriven sound for more volume (solos), put the clean boost in the loop. You won't necessarily get more gain though, just volume.

 

[gonzo]

right, and that makes sense, but i've gotten more clean boost into other amps (with a dirty channel) than the good ole boogie....
so, i know there's something special/different with the gain stages in the boogie design....

ok, so what about dropping the V1 from a 12ax7, to a 12at7, the idea being to clean up the first level of preamp gain, so i can hit it a little harder from the 'outside source' ?

 

[LithiumZero]

That may work or just lower the gain

 

[gonzo]

lower preamp gain would be fine with me....
i'm driving the amp harder with an attenuator, to get more output distortion anyway.

i like that sound better.
i'm pulling the full output off with a palmer pdi-09 for recording.....
so i actually need less gain, and less compression going in....

 

[sbalderrama]

If you are overdriving the output section you arn't going to get much if any volume boost either. You have to have headroom available all through the amp to get a volume boost if the boost is plugged in the front. You can overdrive the preamp and boost in the loop if the power section has headroom available, which is basically how the SOLO function on Mesa's works. The SOLO function loses effectiveness as the amp gets louder though, because the headroom available in the power section goes away.

 

[gonzo]

well, i'm not really going for more volume, because this is specifically a recording aspect.

but, i'll try to explain better...

i want the EFFECT of being able to drive the input harder, from the front side, and back off the preamp gain, and still get that 'touch sensitivity' you get from having the amp all the way to the edge.

then, i push the amp harder at the output, to get the kind of distortion i'm really looking for....

the amp, as it is, doensn't quite get there by itself...
and just pushing it with an overdrive or running the preamp hotter doesn't get me there.

i can ALMOST do it, with the clean channel wide open....

 

[LithiumZero]

Your original post said that you were looking for more volume and gain for solos in a live application so that's where I was coming from. Your last post states that it's strictly a recording situation. Which is it?

 

[gonzo]

strictly recording...
but the idea of it comes from a live situation..

i want to apply that same capability, but dial it in a bit more, for the recording session.

it's kind of like the idea of 'cooking' the amp...
getting the front end of the preamp, in it's most optimum gain structure, to work with the power side.....

i can't find what i'm looking for, with just adjustments of the master, vol1, and lead drive..

so i'm thinking, cleaner V1, pushing a slightly hotter signal on the front side, driving the master harder, and backing off the lead drive a bit.....

there's this subtle changeover that occurs..

when the passive signal from the guitar (i hate active pickups) is slightly boosted...

it's easy to get on the clean channel..

but then, i don't have the depth, the 3D quality i'm looking for, without the extra gain stages.

it seems that the harder i push the PRE-preamp, the more it restricts.


and i'm thinking, the v1 choice of tube, is key.

 

[LithiumZero]

sorry bro...I got nothing

 

[gonzo]

thanks anyway...
appreciate the effort and time...

 

[Dutchman]

Thr Barber Launchpad may get you there.

It's designed to "cook" the input tube.

http://www.barberelectronics.com/LaunchPad.htm

Here's a little more info.

"How To Cook A Tube Amp"

http://www.tpngear.com/forum/index.php?showtopic=169&hl=launchpad

I always have allot of fun with an Ernie Ball Volume Pedal in the Effects loop, with the first gain stage dimed.

Let me know what you come up with, cuz I'm sure I'll want to try it