NAD 1987X 50W Plexi RI with Pat Sullivan Mod???

[Gridlock]

NAD 1987X 50W Plexi RI with Pat Sullivan Mod???

I just bought this amp last night from GC. It was advertised with the Pat Sullivan mod but no one there could tell me what the mod was. The amp appears to have a power scaling knob on the back panel (in one of the speaker outputs) and a small toggle switch on the front panel. The back knob seems to cut the power and doesn't perform like a master volume. The front switch seems to cut the power even more but the sound degrades.

It has great-warm tones at low volumes using the back power scaling (I think) knob.

This maybe my favorite Marshall yet. I get to crank the amp tomorrow when the wife's away and it should confirm my thoughts.

Is anyone familiar with this mod? I could not find any info on the web.

Any info would be appreciated.

Thanks,
Doug

[surfnorthwest]

Well congrats on your new amp. I have never heard of Pat Sullivan so I have no idea about this mod. The pot on the back of the amp, are you sure its a form of power scaling and not a master volume?

The toggle switch could be a mod that switchs the amp from 50 to 25 watts. Bottom line is if the amp sounds good for your needs, mods are usually pretty easy to reverse if you don't want them.

[Gridlock]

Thanks Surf. I am not really sure what the pot on the back of the amp does. I am assuming that it is power scaling since it did not really react like a master volume at lower volumes. I couldn't really crank the amp yesterday but will get a chance today and maybe I can figure it out. I traded my Mesa DC3 for this amp. I am an all Marshall guy now and have owned Marshalls since 1977.

I would have never considered a non master volume amp without a master volume or power scaling mod since I rarely get a chance to get loud. I’m glad that I decided to try this amp and work out a fair trade with GC. The guys at the two Guitar Centers near me are pretty good and will usually work with me without me taking a major loss in the process.

The amp sure sounds good as is. Very warm when I jump the two channels, have the modded toggle on the front panel up (full power I assume), and almost straight into the amp with just a tad of reverb using my Holy Grail. I used my Fulltone OCD with good over-driven tones at lower volumes. I would have never thought a non-master volume amp could sound so good at lower volumes.

Thanks again.
Doug

[surfnorthwest]

The amp sure sounds good as is.

There you go then.

The mod is going to drive you crazy until you know what it is, I would be the same way. Enjoy the amp and when you a get a chance to take to a good amps tech let him take a look see and tell you what's going on. If it were my amp I would bring it in anyways to have a look see at the tubes and bias since you don't know the history of either.

[Gridlock]

Not knowing what the mod is will definitely drive me crazy. I have a shop close that sells vintage gear and I trust the techs. I’ll drop it off next weekend for a check up.

Thanks again. You guys are great.

[DSL100 Dude]

Congratulations on a super cool amp!

Can't say as I know a darn thing about the mods that are on there but it seems to me that you are already finding some sweet tones out of it. I too would think that it may be more likely that it is a PPIMV which is considered a VERY GOOD THING. A LOT of fellas have their NMV amps modded with a PPIMV.

[Herbvis]

It could be a PPIMV

[Herbvis]

Probably a PPIMV

[Gridlock]

I had the amp checked out by my local guitar/amp shop shortly after buying it and the tech said that it was a PPIMV mod. He said that the mod was done very well. He did replace the two volume pots that were a little scratchy with better quality pots. The mod works great and I doubt that I would have bought the amp without the MV mod. It would just be too loud for my needs. The amp is a 1994 pre loop model; it sounds great, and is a keeper. Thanks for the input.

[Gridlock]

It is a small world thanks to the internet and these forums. Pat Sullvan, that person that modded my amp years ago contacted me after a friend of his saw my post in either this forum or the Marshall Amp forum. Pat seems like a great guy. He gave me details what the mods were on my amp and how to used them (one mod in particular).

Prior to speaking to Pat, I had and the amp checked out by a very good local tech and he said that the mods were very professionally done and that good components were used.

Funny thing, my amp shows up approx 1200 miles away from where the mods were done years ago and I get to email and speak to the amp-guru in person years later (my amp is a 1994 model).

Thanks Pat for your help and thanks Surf for helping us make contact via this forum.