The Amp Garage

Dave, from personal experience, I have a 50w #102 and a 100w bluesmaster, neither of them do that crunch , clean/slightly broken up sound well. I've just learned to accept that's the way they are. I have a JTM45 and a rocket that will do the crunch a lot better :) And, they're both a LOT easier and...

Have fun ;) I've got to admit, I'm having trouble conceiving how to engage PAB on clean, and still have it available for OD as a separate click. I did this on a build but the topology was dual MV's and HRM. Thus, enabling a switchable PAB in both modes in which the boost in the OD mode was a simple...

Have fun ;) I've got to admit, I'm having trouble conceiving how to engage PAB on clean, and still have it available for OD as a separate click. Also, the PAB that I am using is applying resistive grounds to Mid and Bass like this: http://ampgarage.com/forum/viewtopic.php?t=15229&start=15 Maybe sle...

I know we're talking different amps, but i just checked a 2nd/3rd gen type and my cleans are sparkly all the way up, and just filthy with the PAB. That amp is a Classic stack with the 22M resistors separating bass top and wiper, and treble bottom and bass top. I understand that the point of PAB is ...

Well, you're not gonna hurt anything to get them super low. Might as well drop em down to 120V so you can see what it sounds like at an extreme ;) To me things just get too inarticulate when they are that low. I would think , though, that you would have nothing sonically to gain under 170V on V1 Th...

Yes sorry 22M. You can ground the junction on the grid side of the cap then. That should get more distortion coming out of the clean stages. I put this on a switch in the back. This got me almost there. It gives me a little bit of breakup on clean side starting at about 2-3 oclock, and has a good b...

Not difficult at all to change the PI. You should be able to parallel in a lot of stuff. The BM has a Marshall tone stack, and PI, basically. I think the plates/cathodes are different, but nonetheless I would start with the PI and see where it gets you, then hit the tonestack, then hit the plates. ...

Have you tried any of the Bluesmaster arrangement? Being that anything you do to the clean side will affect the OD side, and the fact that everything is a compromise, you may consider changing the PI to a Marshall/Bluesmaster. Heck you might even like it better. The BM cleans are great, and the gri...

Thanks Martin. I will try that.

martin manning wrote:Dave, did you try disabling the LNFB? It's easy to do if you have the cap at the plate followed by two 10m in series. Just ground the junction of the 10M resistors.

Thanks Martin. I made mine more like the 124. Cap between the two 22M. I noticed you said 10M. Are we talking about the LNFB at V1B?

Clean channel still no dirt, and when volume maxed, becomes louder than OD channel with level maxed . Am I understanding you correctly? The clean channel maxed is louder then the clean channel maxed into the OD channel maxed? IF that is the case, then I would check every value of every resistor and...

I changed the 18K B+4 dropping resistor to 22K. Attached before and after readings. That dropped B+ 4 and 5 down about 15V, and the V1 & V2 plates about 10V. Not a lot of audible difference. Clean channel still no dirt, and when volume maxed, becomes louder than OD channel with level maxed. I then r...

I believe most people are using PAB as a boost in clean or OD, not for adding distortion to the clean. It will make the OD more distorted, though, and increase the overall volume. That's the way I want to use PAB. I just mentioned PAB, because it is the only way I can get some dirt out of the clean...

martin manning wrote:I'd try reducing the preamp voltages, maybe 15V, and see if you like that better. I'm still not sure that PAB is intended to dirty up the clean as much as to provide a volume boost to whichever channel is in use.

Thanks Martin. I'll give it a shot, and let you know how it works out.

Thanks Martin. Depending on tubes used. My V1 voltages have varied between Pin 1: 190V-194V Pin 6: 196V-201V.