Phoenix Gold Phorum

I'm getting started on my build soon. It's going to be a 16ch active 6.2 upmixed system (2 Alpine F1 DSPs).

I have a big stack of MS/MPS amps I'm going to use. 9 in total for this build.
3x MPS-2240s (Front/Rear/Front and Rear Center)
3x MS-275s (Front/Rear/Center Midrange)
3x MS-2125s (Front Midbass/Front Sub/Rear IB Sub)

I'm going to replace the input capacitors. Possibly the rail caps. Just curious if anyone knows of any modifications I can do while I'm in there. I'd like to bypass the tone controls and such. Can anyone recommend an op-amp upgrade? Anyone have any how-tos for modifications? Does anyone have a circuit diagram for these amps?

Also, Which rail caps are you guys using?

There are dozens of modifications that can be made and I do many routinely for customers. For MS amps, the most popular are bass boost delete, high end op-amps, audio grade coupling caps and less routinely, completely recapping the poweramp with higher quality parts.

The above mentioned are in addition to the standard power supply recap and typically optional rail cap recap.

There are no service manuals for PG amps, but there are some schematics available in the wild. With the exception of ZPA amps, every single US made pre-rodin PG amp I've worked on has had a virtually identical poweramp. Power supplies are very similar as well, but regulation schemes and rail voltages vary quite widely. Preamp/crossovers are the biggest difference between amp lines and models. The point being, you can use a M series schematic to understand pretty much any PG poweramp, the design didn't change.

I don't want to be a Debbie downer, but based on the questions you are asking, I don't think you have any business attempting to make upgrades and changes. For a novice, just doing the caps on these amps is a challenge and often ends with non functioning amp and a much larger repair bill than the recap alone. I've said this many times before, but if you don't even know how to find the correct parts, then you don't have the experience necessary.

Good luck,
Jason

Well said!!! I have a PA4300 that I need to send to you.. it’s going to go with the 2) 4020UHC that you’ve already restored.. those 3 amps together look insane.. the 2 that you’ve already restored look insane together let alone..

From what I understand Jason knows his shit.. I personally think it would be best to have him properly restore all your amps at the same time so everything is 100%.. you have a good vision and it would suck to get everything installed and run into amp issues. I know I’ve had my fair share of amp problems.. I had a brand new Frank and a sofa catch fire..

I'm extremely backlogged at the moment, but I'm glad you like those earthquakes and that you were able to work out a deal with my good friend Yusef.

Just so you know, only one of those two earthquakes were completely gone through from stem to stern (the one that is in nearly flawless condition, it had a complete recap including all the wet caps in the poweramp, as well as power supply rebuild on one of the amps and I think that one was the one that got all new output transistors on one board). The other I was just asked to repair. It had had some hackery done to its input board and ±15v power supply. I fixed all the bodged stuff, wound a new transformer for it, and I think that was it on that one. They both were thoroughly tested though and performed flawlessly.

They are beasts of an amp. I really don't much enjoy working on them. Between the 1/0g direct leads and sheer physical size, they are difficult to wrangle and position, however they are some beautiful pieces of old school goodness. I'm happy I could service them.

Thank you,
Jason

I have a lot of pictures of the work if you would like me to post a thread about them. I've been avoiding posting non pg repairs just because this is a brand specific group.

a ms upgrade thread would be excellent.Looking forward to it.

Hello all. I just found this forum and have 2 MPS-2240 amps that were last used in the early 2000’s. I saw Jacampb2 post about going through the amps and repairing them. How do I get in touch with someone to go through my amps? TIA