MPS-2500 (lots of large photos inside) FIXED PICS

Audiophiliac · Post by **Audiophiliac** » Fri Sep 28, 2012 3:55 pm

Big thanks to nutxo, this is my latest acquisition. This was one amp that I drooled over more than any other back in the day and have never had a chance to own until now. For anyone wanting to buy something from nutxo, do not fear. He said he would pack the $%@ out of it and he did. Pretty clever cutting styrofoam to fit around the terminals so they did not break.

Anyway, I have plans to get this completely redone. First I will clean it up good to see what I have to work with. Then it will probably make a trip to Altser. I have talked briefly with Matt about getting it re-coated and screened. I have a color scheme in mind that I think will be awesome.

I am contemplating replacing the endplate with one of the later ones.....I think they look more symmetrical....but have not decided for sure. The way it would be mounted, you probably would not see the connections anyway.

I see where the remote turn on wire was soldered into place. I am not sure how it got broken....the guy I bought it from said the caps were replaced a while back. I am not sure that is true. Take a look at the photos and tell me what you think. I was kind of hoping it was a rev. A board, but it is rev. B. Still...an early unit. I do not see any evidence of any other damage on the board which is good.

Just my luck, a MPS2500 and a MPS2240 just showed up on Craigslist locally today. They are both beat to hell, but I might see if I can talk him down and have a spare.

Enjoy the pics!

00goobs · Post by **00goobs** » Fri Sep 28, 2012 5:28 pm

Maybe it's just me, but I see red question marks... I recently acquired 2 MPS-2500s and MPS-2240s. I think my favorite was always the MS2125. I didn't even know the MS2250 existed until I got on the Phorum...

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Post by **ttocs** » Fri Sep 28, 2012 7:05 pm

Starunit10 · Post by **Starunit10** » Sat Sep 29, 2012 4:43 am

can't see pic's

00goobs · Post by **00goobs** » Sat Sep 29, 2012 3:24 pm

Those bus bars look closer together than my MS amps. I'll open up an MPS to see if there is a difference...

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Audiophiliac · Post by **Audiophiliac** » Sat Sep 29, 2012 3:39 pm

Yeah they seem closer than other amps i have seen too. There is a plastic coating on them also. Maybe to protect from them somehow touching? Could be something they changed in later revs.

LowandLoud · Post by **LowandLoud** » Sun Sep 30, 2012 11:20 am

I am no guru but those caps all look original to me.

JayGold · Post by **JayGold** » Sun Sep 30, 2012 11:55 am

Audiophiliac wrote:Yeah they seem closer than other amps i have seen too. There is a plastic coating on them also. Maybe to protect from them somehow touching? Could be something they changed in later revs.

Most if not all MS amps have a clear plastic sheath on the buss bars to protect them from arcing on each other since they tend to flex easily from their lack of thickness.
I'm no guru either, but the caps all seem to be original since they exhibit the PG round decal of "date approval" on them.

At least the remote lead solder job is clean, I've seen much much worse attempts.
The board could use a good cleaning with 99% IPA.

Look like the sink and chassis are in great condition, most have rust and cracked finishes.

zeropoint0.5 · Post by **zeropoint0.5** » Sun Sep 30, 2012 1:05 pm

i just would not power it up in this condition.....

new ps caps and silpads for sure , but if you see that diode

next too the glass fuse, probably something has happened or repaired before.....

If you wanna enjoy this amp, let somebody like Eric D or Valeks check it out first.....

sometimes it's better to have patience then to say

i quess you will enjoy 1000W rms at 1 ohm brigded very well........when it's fine.....

good luck

00goobs · Post by **00goobs** » Mon Oct 01, 2012 4:05 am

zeropoint0.5 wrote:
i quess you will enjoy 1000W rms at 1 ohm brigded very well......

Will these amps really do 1000w at 1 ohm?

Mr. Wild · Post by **Mr. Wild** » Mon Oct 01, 2012 9:43 pm

They are rated at 500W RMS bridged @2ohm. So in theory that's 1000W @1ohm but prolly just dynamic, not RMS.

They are supposed to be stable @0,25 ohm stereo which is a bit rich.

nico boom · Post by **nico boom** » Mon Oct 01, 2012 11:07 pm

Very mint amp with all original caps.
Some repairs have been made ,but [by what I can see on the pics] no big ones.
It needs new caps like mentioned before; if you're not up to it yourself, have it done.
I'm under the impression some members here confuse the the numbers of the MPS2500 with the MS2250....
The MPS2500 really was PG's flagship in the '90s ; around here there were only a handfull available as where the MS275 and MS2125 were "THE THING" at shows. A car with a MS1000 installed was surrounded with a crowd all day long.

The best cheater-amp however defenately was the MPS2500 if you knew how to properly wire it up and it left people in disbelieve about "only ONE amp's " clarity and power that way.
Have it restored to it's full glory and ENJOY this amp!
Nico

zeropoint0.5 · Post by **zeropoint0.5** » Tue Oct 02, 2012 12:28 am

00goobs wrote:
zeropoint0.5 wrote:
i quess you will enjoy 1000W rms at 1 ohm brigded very well......

Will these amps really do 1000w at 1 ohm?

i was told before......and not by the first the best person

the original ms2250 will give 1K rms at 4 ohm

the ms2250TA will give 1K rms at 2 ohm

the mps2500 will give 1K rms at 1 ohm

i have not tested this myself. but i know somebody who has a mps2500. when i have the chance,

i will let it bench test at 1 ohm brigded !!! but yes i would do believe it will do 1 K rms at 1 ohm , yes.

i would not hesitate to use a mps2500 at 1 ohm brigded....but i would not use it without a shroud.....

00goobs · Post by **00goobs** » Sat Oct 13, 2012 4:33 pm

Is there anything different component wise on the input stage to use an MPS2500 over an MS2125? (If total output weren't a deciding factor.)

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lilviper · Post by **lilviper** » Fri Nov 09, 2012 7:01 pm

whats wrong with the caps?

I know they age, but is there a big push to replace them every x years?

Post by **ttocs** » Fri Nov 09, 2012 8:18 pm

problem is that when the caps go bad, THEY REALLY GO BAD! These vids were all done on purpose to pop the cap by putting too much power on it. But when a cap goes it can make a really good sized explosion and end up burning the board and making an amp into nothing more then good for parts.

http://www.youtube.com/results?search_q ... 9y4l3ZhZPs

PG just didn't get the right/good stuff and after about 10 yrs you will need to keep an eye on them. Often they will start to expand and you can see it stretching the heat shrink around them. They will eventually start to leak fluid out of the bottom and that fluid can short out and cause a big pop.

We recomend at the very least that you cut a piece of paper into a strip and slide it under the cap. If it comes out wet/damp then you definitly need to change them out. But if its an amp you plan on using for a while I would just swap them out to begin so you know they are safe.

nico boom · Post by **nico boom** » Fri Nov 09, 2012 8:26 pm

lilviper wrote:whats wrong with the caps?

I know they age, but is there a big push to replace them every x years?

THERE'S PLENTY OF INFO ON THIS FORUM ABOUT THIS MATTER ALREADY; I ADVICE YOU TO READ IT FIRST.

lilviper · Post by **lilviper** » Fri Nov 09, 2012 8:44 pm

nico boom wrote:
lilviper wrote:whats wrong with the caps?

I know they age, but is there a big push to replace them every x years?
THERE'S PLENTY OF INFO ON THIS FORUM ABOUT THIS MATTER ALREADY; I ADVICE YOU TO READ IT FIRST.

right..

lemmie find mr. search

lilviper · Post by **lilviper** » Fri Nov 09, 2012 8:46 pm

ttocs wrote:problem is that when the caps go bad, THEY REALLY GO BAD! These vids were all done on purpose to pop the cap by putting too much power on it. But when a cap goes it can make a really good sized explosion and end up burning the board and making an amp into nothing more then good for parts.

http://www.youtube.com/results?search_q ... 9y4l3ZhZPs

PG just didn't get the right/good stuff and after about 10 yrs you will need to keep an eye on them. Often they will start to expand and you can see it stretching the heat shrink around them. They will eventually start to leak fluid out of the bottom and that fluid can short out and cause a big pop.

We recomend at the very least that you cut a piece of paper into a strip and slide it under the cap. If it comes out wet/damp then you definitly need to change them out. But if its an amp you plan on using for a while I would just swap them out to begin so you know they are safe.

Ok... that makes sense.. my MS2250 blew 2 of the 4 caps on the PS in 1996, i sent it back and they fixed it on warranty. looking at the caps in my amp..all 4 have the same markings. i bet they replaced all of em

Post by **ttocs** » Sat Nov 10, 2012 5:03 am

take a peace of paper under them and see if comes out wet or dry. But if it were my amp I would break the bank and replace the caps to be sure it doesn't do anything that it would not like... If you are after someone to tryout jl

Post by **Eric D** » Sat Nov 10, 2012 10:06 am

The caps used in these amps were great quality at the time they were purchased by PG and installed in amplifiers. PG did not skimp by buying them.

PG also had no clue that 10 years later they would start leaking and failing. I have come across some other products using these same caps, and they had the same problems with leaking.

I found a computer power supply with these leaking caps. I also found a few motherboards with the same brand and series of cap (just smaller) which were leaking.

Also, my guess is this is a MS2125, not an MPS2500. The older MPS2500 used 35V rail caps to my knowledge, and the MS2125 used 40V rail caps.

Later MS2125s moved to 50V caps, and MPS2500s might have moved up to 40V, but that I am not certain.