Looking for a DS-4 control pedal if anyone has one available.

Ok that's an old one, get a OPA2134AP for U4, don't change U9. Now the TL072 is not obsolete at all but the OPA is better.

I think it’s version 1 ca.2003

No worries  , IIRC the most fiddly part of the mod, and where it helps having another pair of hands (I helped MikeB do it) to gently leaver the back mounting plate away enough at the corner to get the new rear jack socket located, which is how we did it.  Otherwise you have to undo all the rear connectors (quite a few) from the back plate so the whole back plate comes away, and then re-assemble them all, tidier but takes much longer.  Upside is once it's done, replacing the front jack should you need to in the future is easy, just have to make sure you source the long collar switchcraft (or equivalent) jack socket so it handles the addition thickness of the MP-1 front panel. The front jack IIRC is a switchcraft L12A (well it is for MP-2 and I assume the same for MP-1).

Hey Gang,

    I've been following these posts, and this whole thread has been entertaining. Richard, you've pretty much covered all the bases regarding what's been going on here, and yes, you are almost spot-on about the V2.0 upgrade. That upgrade came about because of a few bugs in the original release of the MP-1. There were a few parameters which didn't react well if you went over certain input levels and the MP-1 would make a couple of really unpleasant noises. So they got those issues tamed down in V2.0.

    The fact that it coincided with the release of the "Vintage" Split-Stacks was just timing. In the late 80s, more players were talking up a storm about earlier Marshall speakers sounding much warmer and (in their opinions), better than the speakers Marshall was putting out at the time. So in response to this, Dave Tarnowski and Co. started measuring EQ curves from these old speaker cabs and came up with a small EQ filter circuit that they started putting into the Split-Stacks and named them "Vintage" split stack cabs. The truth is they still had the same budget-friendly 50 watt Celestions that the stock cabs had, they just had this extra little circuit in them so you could switch from vintage,(warm), to modern, (not-so-warm) speaker cab tones.

    The extra presets included in the MP-1 had a few new tones that utilized the stereo chorus and split stacks to create a wider soundscape with the guitar and a single MP-1 rig, which it does very well by the way. If you added independent delays to each channel like I did, then you started getting into pro rig territory. Add a dry center channel and you're there with all the monster guitar players of the 80's, Van Halen, Vai, Lukather, Huff, etc. Instant Wet/Dry/Wet rig. V2.01 added a few more tones but mostly with the stereo chorus for further stereo rig tones.

    As for Nuno, I do recall his rig used a Boss Tuner, Distortion, and EQ pedal on the floor in front of him. I'm not sure about the distortion pedal though. I think it was the Boss SD-1 Overdrive, or maybe SD-2. It was definitely the yellow one, and not the DS-1 distortion.

Thanks a lot for all the information- really helpful, cheers.

I will go with the rear mod then- thanks again for your advice

Hey Gerry, I think those are pretty hard to find (unless someone has a spare).  IIRC they mount to the PCB.  Given that it's the one part of the MP-1 that takes allot of ware and tear, I reckon it's a better idea to do the rear jack mod as that replaces the front jack with a standard (longer thread variant) socket, which can easily be replaced in the future.  Maybe someone who's done the rear jack mod has the original in ok condition they could let you have?

Hey Gerry, yes 1 - 29 are the same in v1.x and v2.x, they just added a bunch more.  Also I suspect (Harley will probably know) the Vintage Split stacks came later and co-coincided with the v2.0 EPROM release so they put in a bunch of patches for them (bank 6) as well as some new ones.  It's always an issue when you pick up a 2nd hand MP-1/2, do you keep the patches from the previous owner or start from scratch. The last EPROM update was v2.01, as I said previously, worth doing, not expensive and relatively easy (i.e. buy 2.01 EPROM and swap it in.)

Hi, does anyone know where to buy the front instrument input for the ADA-MP1? Mine works, but is a bit loose, and I have read this is a common problem with these units.

http://www.marshalljmpmodshop.net/ has none in stock
I know that he also sell's a mod to convert the rear input from line to instrument, but I would be happy for now to just get the front input fixed or replace.

Thanks.