i've attached a pic of the slop resistor for you, but i have a few suggestions/questions

First of all as T Wilcox suggested, you may want to experiment with the OD trim. By adjusting it you can go from slight overdrive to all out chaos, but it starts to get fizzy as you turn it up.
What kind of preamp/power tubes are you running? Different tubes can yield different results

What kind of speakers are you running? The OTS series is kinda picky when it comes to speakers.

Are you running OD and PAB at the same time? If you aren't you may want to try it. Without the PAB on (which in my opinion should be renamed Tone Stack Lift, since that is what it does) in OD mode on an HRM amp you are sending you signal through two tone stacks which can make your town sound either muddy or harsh depending on your settings.

Also, the Preamp (clean) volume will effect the overall gain as well, as V1 cascades into V2. In otherwords if you crank the clean gain and use your guitar volume to get some nice dirt when pushed, when you kick in the OD channel your OD can be very gainy and fizzy as well.

A C-Lator helps alot, but isn't technically necessary although, mine really woke up and sounded awesome with it

As far as the slope resistor goes, the common mod is to switch it to 68k or 100k and to switch the main tonestack bass pot from 500k to 250k, and i even considered doing it until the amp got nicely broken in, got some great speakers, played around with different tubes, and adjusted the OD tonestack with the PAB engaged, adjusted the OD trim, and got a c-lator.

Hope this helps, and let us know the answers to the questions if ya can; AND above all, remember all that matters is that you find YOUR tone and YOU like the way your amp sounds

Gregg

i'm wasn't as handy a few years ago as i am now so i bought one of these and used to use it. with it you can drive up to six amps or devices quite handy, but if the venue you are playing at ahs bad grounding it can be kinda "shocking"

http://www.mojotone.com/guitar-parts/Rene-Martinez-Texas-Guitar-Whiz/Rene-Martinez-Texas-Guitar-Whiz-Signal-Splitter

Making your own can be fun though. I will be making a true bypass switcher to switch my non true bypass effects in and out of the line/loop and i'm looking into winding my own pickups and making my own fuzz.
 i use a series of y-cables now, and i'm sure i lose signal, but it works for now.

Gregg

Mine was a lil fizzy the first few days. Let it burn in before you change anything. The CD player/MP3 player is a great method. Just be sure the volume is turned down a bit due to the impedance difference

FWIW i am currently running a Sovtek Mig 50 and an Ampeg J12-R along with my HRM BM 50 right now and they each balance the other very nicely. The Sovtek is about on its last legs, so i plan on having Nik build me a Plexi 50 modified to run 6L6's to kinda replace the Sovtek and mount it into a 2x12 cab. Like Greg said though, find an amp that balances out your FM50 and you will be a happy camper

very cool! Plexi 50 2x12 will be my next amp!

Hywel, it's two pieces. Hope this helps!

Yes it can i'm going to buy a couple more sets to have on hand just in case. These two were pulled from a mighty wurlitzer apparently. How cool is that?

The ANOS GE Long Plates sound beautiful in the HRM BM!!! I originally had A GE Long Plate in V1, A JJ in V2, and the Mullard CV 4024 in V3 I also installed TAD 6L6WGC-STR's in V4 & V5. With the JJ in V2, there was a ton of gain available, but it was a bit harsh and grainy. I put the other GE Long Plate and V2, and voila! Nice warm full overdrive!! I biased the Power tubes to 40 mA and i have to say the amp is very balanced now. Nice and bright, but not too bright, very warm, and "3D" as they say with a lot of depth, and the OD tone is outstanding. The Weber 1265 alnico pre-rolas are a perfect match for this amp... i am very pleased!

Here's a more "Hi-Res" Version with the C-Lator as well

Thanks!

i got from GabKits.com, so basically Anthony @ StageCraft and his crew built it, i do believe. i'll take a look at the baffle in the am and let ya know!

indeed, nothing is great and FREE!!

hmm i was looking at the layout and thinking along those lines... i think i'll just take it my tech and let him figure it out 

ah, good point! told ya i prolly wasn't thinking straight 

So, I am probably going to swap out the slope resistor in my Bluesmaster from a 47k to 68k or 100k to tighten up the bass response, but i got to thinking about a slightly different approach and wanted to run it by you guys to see what you think. If I recall, if you wire up a potentiometer using only two lugs (input and wiper) it will act as a variable resistor or rheostat. I was thinking of putting, say a 150k Linear pot on either the front or rear of the amp, and running leads to the spot on the board where the slope resistor is, there by making the resistance adjustable. I figure i can then adjust the pot while checking the resistance and mark the spot on the travel of the pot for different resistance levels so i can have a preset of sorts, and be able to adjust it on the fly to suit my mood. Do you guys think this would work, or would i need to have a resistor, say 100k or 150k on the board and the pot? i'm thinking just the pot would do the trick, but it is late and i may not be thinking straight...

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