Ms and zpa series amplifier modification database. DIY!!!

[freshkryp69]

Im one of those DIY,,jack of all trades kinda guy's with about $20,000 in snap-on tools and a killer PACE de/soldering station and a small entry level o-scope..and the ability to not leave well enough alone...
I have the amps tore apart now (ms275 and ms2125) and Im in the process of upgrading everything that I can like P/S caps and the rail caps, with audio grade caps...Ive installed irfp054's in the p/s to insure reliability if the input voltage gets to low.and Ill be switching out the bi-polar outputs (kinda hard to fit the oldladies brain in the amps so..lol) soon as I find the best replacements available SQ wise..which are going to be toshiba(2sa1943/2sc5200) or some motorola's maybey on-semi? Im totally open to recomendations and part #'s would be great!!!

Im needing some info on the pro's and con's of totally bypassing the gain stage and taking out all the eletrolitic caps in the signal path making it a pure amp..(kinda like a zpa with no opamps). my HU is a drz9255 with 8 volt preout's..need to make sure the amp will survive with that voltage?? I dont want any eq's in the system,my hu has 2 options of eqing if I need to make small adjustments.
the ms275 is going to run the new scan speak tweeters and the ms2125 scan speak mids..I havent decided on 4 or 8 ohms yet?? that depends on if I can get the rail voltage up a bit to compensate for the lower watts at 8 ohms?? I understand the headroom thing but, I like it loud,but crystal clear..
I remember reading on here and the old P/G forum about doing some of these mods but it seems some posts have been deleted and cant find any of that info anymore? must have been because of who wrote them???anyways.. if any of you guys in the know want to share some info I would greatly appreciate it!!

we need a sticky with a list on what can be done and how to modifiy these badass pg amps and the trustworthy people that can do them. the pro's and con's to the modifications..what parts to use that are the best avaliable like op-amps, audio grade caps,rewound torrids,circuit mods/deletes...a real diy section with step by steps showing how the above average guy thats ok with an soldering iron and a lil know how and guidence from us that do these type of things because we cant leave well enough alone can complete..I think it would create alot of interest and we all could learn some cool shit!
lets get out of the dark myserious world of amp modification and bring it to light..and educate all us P/G addicts..? all worthy P/G models should be included and the stages of mods that one could make to their paticular amp.
how many times have you looked at your amp wondering what could be done to make it better or different from the next guys,how much it would cost..and just put it off because most of us dont know how to do it or have that someone to ask that knowledgable and willing to help..we could change that! we should keep all this info on one topic , not all spread around through 1000's of posts.

Im not trying to reinvent the p/g amp...I just want my ms's and zpa's to be the very best they could possibly ever be..know what I mean??

who's in??

[fuzzysnuggleduck]

EricD has done a lot of this work in the past and documented some of it on soundbuggy.

MS specific stuff (although not a lot of information):

http://www.soundbuggy.com/Eric/Car%20Au ... index.html

An index of all his car audio stuff (including repair and upgrade work):

http://www.soundbuggy.com/Eric/Car%20Audio/

[spaceace60]

new to posting but i have a rt66 and was sent a mod sheet from the Pg tech dept(converting a 6ch to 4 ch!) but can't understand it

Route 66 Signal Routing Mod.pdf

(32.05 KiB) Downloaded 276 times

so if someone could kindly open this file and guide me thru it that would be great! or better yet call me when u do! (814)493-3173 thanks Jim btw my goal is to run the m44 section bridged on front mids(polk sr6500 6.5's and the m25 section on rear 6.5mid/bass(kickers)

[Mr. Wild]

Using audio grade caps for replacing PS and rail caps may not be an upgrade. These caps need to be designed for switching PS filtering purposes, not signal path.

Just a FYI, because I don't really know what kinda specs ""audio grade" caps carry and if they are OK for PS use. If their ESR is high and ripple current low, they might fry.

[smgreen20]

Did you modify the 9255 to get 8v out of it? Normally, it's 4v. If you turn the bass and treble up you can get 9v out of it. Just food for thought.

[kg1961]

hmm i have a normal one on my gear......9255 imo is one of the best