Something doesn't sound right. My amp is a HRM bluesmaster, but I believe it is supposed to work the same way as yours. The master volume knob in the power amp section controls the overall clean channel volume, whether or not the pab button (the green one) is pressed. When the red button is pressed, the level knob in the overdrive section becomes the moster volume. The green button should work in both sections. Check the switches on the back of the amp - they should both be set to the pedal side for the footswitch to work correctly.

Thanks Greg for the feedback....I mean sustain.
I will work on this thang. Like your videos on Youtube.

Has anyone with an HRM adjusted the internal post overdrive tone stack and if so what did you do to it and was it easy to do and did it have the impact you were looking for?

It was quite a hard choice for me, as I'd had no first hand experience with the many variations of the amps, and only had recorded demos to go by. I was swayed towards the bluesmaster because of the promise of the fender blackface sound of the clean channel - I really love that sound, and as it turns out it works really well for that. And I figured with the separate set of tone trimmers for the overdrive channel, I could really personalize the drive channel, as I use it a lot, without having to compromise the settings of the clean channel.

50w vs. 100w - this was also a tough choice. At this point in time I'm mostly an at-home type of player, but like to get into the woolier sounds of the amp, without peeling my ears off. Or my neighbors. And even with my little 4x10 cab, this thing gets much louder than I can take really quickly.

Okay, how did I miss that little design difference...
Why is there no FET input on HRM models?

And what is the mod that I've seen, putting a switch (or pot?) in the upper position of the Inputs??

Yes, I got the 50w Bluesmaster. It's been many years since I've played gigs, but I used to play out a lot, and my favorite amps back then were a pair of blackface amps - first a pro reverb and then later a twin reverb. Most of my gigs were as a rock player, so having a good distortion sound was a must, but even so some 75% of my playing on any given gig was with a normal clean sound. So having a killer clean sound made life a lot funner.

And the bluesmaster has the best clean sound of any of the amps I've had since the fenders left - it's a pure joy to play through. And of course the overdrive channel is simply stunning sounding also, but the clean channel has that rich, chimey high end, smooth but roomy midrange that the best amps have. I'm not totally convinced about the low end yet - there's too much of it, and it's hard to find the right setting on the dials to get enough of it, yet still have it tight sounding - there may be more break in time needed, or perhaps some experimenting with tubes. I currently have tungsol 12ax7's and JJ 6L6GC's in there - just standard stuff I was able to get at the local music store.

And I really need to upgrade my speaker situation - the knockoff 4x10's I'm playing through are in the dull and lifeless department.

I find that the way the first volume control works is pretty close to the way I remember the volume control working on my old twin - pretty much clean up until about 7 or 8, when just a bit of light break up starts. I'm playing a strat with emg's through it, but it also has the mid boost knob which emulates the output level of humbuckers - with that turned up you get quite a bit more breakup. One thing I've found with the overdrive channel - the overall sound of it can be extremely affected by the setting on the initial volume control. If you want to get into the heavier marshall/mesa type sounds, turn that first volume control up to 7 or higher, and have the OD gain pot set somewhere in the middle. Back the initial volume off to about 5, and you'll still have a lot of distortion, but it'll be a lot more polite sounding.