Richard,

  I went to the Roland/Boss site to try to get some more info on the effects that are in this pedal, specifically, I'm looking for some kind of chart or table that tells you what kind of effect it is and what kind of parameters I can edit. There is nothing apart from the very brief and nearly useless info in the owner's manual. When I try to do a search on the site for info on the GP-10, it says "No Data Available.

That's very odd for a pedal still in production IMHO. 

 

Dante,

That's a good thing to not have to create new patches for a different speaker cab.

Depending on what kind of feet you want on the cab, you can find a good selection at Antique Electronic Supply. If you want those big rubber ones, you'll probably have to drill into your cab, but looking at your amp corners on there, I think the Fender style sphinx glides will work perfectly and you don't need any extra holes. You just use one of the existing screw holes on the corner.

Very cool 

Interesting, MJMP will no doubt know the answer, hope he comes back on board soon.

Ok, so I've checked some older photos and my other MP-1s and there seem to be two types of transformers. One with black insulation and one bobbin, second type is with 2 bobbins and blue insulation. The blue ones have STEED logo on it. I still have a suspicion that this is a factory made tranny.

So...had practice last night with the new cab. I had it kinda low, just sitting on a 4-wheel dolly, but I was 10-15 feet away, so it was hitting me.

How did it sound? Pretty dang close to the two 1x12s actually. I think a bit more sound is coming out the open back due to the tandem speakers moving around in there, but the tone itself is surprisingly similar. Go figure...of course, I used the exact same two speakers  (Eminence 1218 legend and WGS G12C/S), which are both v30 knockoffs with a smoother top end than the brittle top of real v30s.

Yamaha uses a combination of the Legend 1218 and a Tonker in their 2x12 cab. I may consider a Tonker later

The dang cab fits absolutely PERFECTLY in the back of my little Ford Fiesta, so I guess I gotta keep it I put the cab, my pedalboard, amp head and backpack full of mics/cords in the back and just used the entire back seat for 4 guitars. I'll get a pic of how nicely it all fits back there.

All in all, it's heavy, but not terrible...the H&K Grandmeister fits perfectly on top when you flip the cab vertically (gotta put some feet on that side...hence, the dolly). I'm happy I didn't have to tweak anything, I'd hate to have a bank of patches for each set of speakers. Here's a couple quick pix of the cab sitting on another cab and the back before I wired it up

Update - these Lorantz speakers are fu@@g awesome  . I just had a play through my new cut down rig with my oldest guitar (that I still have), Anson MIJ strat (heavily modified), has a late 70's SD hot staggered strat in the bridge, my old Navarra LP (the predecessor to Ibenez) bridge gold humbucker in the middle, and the original Anson SC in the neck. And just using my standard MP-2 patches, the sound is awesome. I love these speakers (and I've heard a few) and they just keep getting better.  If you are considering new speakers, give these go, you won't be disappointed.  So I went for the 12" 100w as they match up well with my various power amps.  The most popular apparently are the 75w 12".  They are about 1.5kg less weight and have a little more top end (according to the spec sheet).  Moreover Lorantz make a greenback version that allegedly matches the original freq curve. https://www.lorantz.com.au/product-category/loudspeakers/12-inch-guitar/

Hey ddt, no worries, others hear may know more  .  So according to the MDRT instructions, not changing the resistor on the tube board (R9) to 300k will mean the high voltage will stay at 190Vdc and not achieve the desired increase, in this case to 220Vdc and for the MDRT 240Vdc.  However, some may prefer it that way?  SC for example likes his MP-1 stock as he prefers the sound.  He even went so far as to source a very early original MP-1 transformer as ADA did change them a bit in later units, probably when they changed the rear jack to inst level and got rid of the inst/line level top switch and went to v2.x firmware.  The increase in high voltage provides for more dynamic range and opens up the sound.  SC preferred the original tone/sound and, in some ways, I agree with him.

Fantastic! Thank you so much for the info.
Looks like the R9 240k resistor remained in place in this MP-1, so basically it's unfinished business.