Page 1 of 2
Mucked up M50
Posted: Wed Sep 22, 2010 3:40 am
by Kurt Wild
Hi! This is my first post here cause I recently managed to purchase an M50
The seller says it works fine but I'm a bit sceptic. First thing i noticed about it the RCA jack gold ground connection rings are missing. I wonder if they have been taken out for a purpose or by accident? I imagine this might be an issue.
Second thing, behind the RCA jacks, resistors R102 & R202 have been replaced by second order RC-networks. Instead of original resistor R102 it has resistor-capacitor to ground-resistor-capacitor to ground. Same thing with R202. I wonder what this mod is for?
Now if someone could point me at a M50 circuit diagram I would be very grateful.
All ideas and insight welcome as well.
Posted: Wed Sep 22, 2010 6:03 am
by tonym
this happens to alot of PG amps....easy fix.......
rca's are about 10-12 buxs each ....some phorum memebers have some for sale most lilky also...
Posted: Wed Sep 22, 2010 7:59 am
by mhyde71
think i might have the rca adapter you would need to replace that one if you would like.
and yes they are 10$ each, + ship?
now i do have some stuff going to norway (think thats your flag youre waiving), but could drop one in there and i am sure that one of the two guys i am mailing stuff to wouldnt mind dropping in post for you once it gets there in your country.
if that could be of help for you i dont know.
I have had amps still work just fine w/ those neg sleeve covers missing...but not sure how good an idea it is though
Posted: Wed Sep 22, 2010 8:06 am
by stipud
Without the RCA grounds you will get a lot of noise inducted into the system, since they are no longer grounded and will not reject any interference. It should, however, make sound.
With the M and MS amps especially, PG would to make lots of ad-hoc modifications to the circuit boards like what you are seeing. Later revisions of the board would add proper placements for these fixes, to make them permanent.
Now with an amp that old you definitely need to make sure the input and rail capacitors are changed as well, as over time they start leaking electrolyte onto the circuit board, which can short out and cause your amp to burn up, even when the car is turned off!
Posted: Wed Sep 22, 2010 8:09 am
by mhyde71
i see- thx tom
okay very good...perhaps it never made diff for me given i have the rca's grounded to HU behind dash then? idk... maybe than, eh?
so yeah i have that rca adapter piece that looks like you might be in need of...
m
Posted: Wed Sep 22, 2010 8:10 am
by stipud
mhyde71 wrote:i see- thx tom
okay very good...perhaps it never made diff for me given i have the rca's grounded to HU behind dash then? idk... maybe than, eh?
so yeah i have that rca adapter piece that looks like you might be in need of...
m
They should be grounded on both ends for the noise rejection to work properly.
Posted: Wed Sep 22, 2010 8:12 am
by mhyde71
ah ha- interesting
okay well makes sense now that i gave it a moments thought...

Posted: Sun Sep 26, 2010 11:17 pm
by Kurt Wild
I tried out my M50 and sure enough there was tons of hiss and noise esp when adjusting the volume. The RCA grounds are there for a purpose..
Also the channel balance was off. The left channel was much fainter. The overall sound quality was bad or at least strange. Very tinny sound with no bass really, except for a muddy boomy upper bass. Sounded kinda out of phase.
Maybe some WD40 on the gain pot would fix the balance, but the bad overall sound leads me to think maybe the caps need changing. Or is it just the missing RCA ground?
I live in Finland btw, not Norway. I would sure appreciate new RCA jacks if it could be worked out.
Posted: Sun Sep 26, 2010 11:55 pm
by gridracer
Do not use WD40 for electronic equipment it attracts dust use an electrical cleaner for that type of thing. I use CNH electrical cleaner partsexpress sells some to.
Posted: Mon Sep 27, 2010 12:15 am
by blind_ex
mhyde71 wrote:now i do have some stuff going to norway (think thats your flag youre waiving), but could drop one in there and i am sure that one of the two guys i am mailing stuff to wouldnt mind dropping in post for you once it gets there in your country.
looks like Finland to me
jezz, you yanks dont know any other flag than yours do you??
Posted: Mon Sep 27, 2010 12:16 am
by tonym
blind_ex wrote:mhyde71 wrote:now i do have some stuff going to norway (think thats your flag youre waiving), but could drop one in there and i am sure that one of the two guys i am mailing stuff to wouldnt mind dropping in post for you once it gets there in your country.
looks like Finland to me
jezz, you yanks dont know any other flag than yours do you??
its the only that that counts.....
Posted: Mon Sep 27, 2010 12:21 am
by blind_ex
tonym wrote:blind_ex wrote:mhyde71 wrote:now i do have some stuff going to norway (think thats your flag youre waiving), but could drop one in there and i am sure that one of the two guys i am mailing stuff to wouldnt mind dropping in post for you once it gets there in your country.
looks like Finland to me
jezz, you yanks dont know any other flag than yours do you??
its the only that that counts.....
yeah right, thats what You think.......

Posted: Mon Sep 27, 2010 1:02 am
by Kurt Wild
Posted: Mon Sep 27, 2010 1:55 am
by gridracer
Even Canada is 4 points higher than the USA
Posted: Mon Sep 27, 2010 3:19 am
by Eric D
I think it is funny anyone would expect an American to know a flag of any other country. Knowing 51 is hard enough, and few Americans can accomplish that over their lifetime. I am sure I know more other country flags than I do US flags, and that is personally sad on my part.
Posted: Mon Sep 27, 2010 5:42 am
by ttocs
I think it is certainly more common in europe that people would know the flags of the surrounding countrys and that is no different then any american as I am sure we all know the canadian and mexican flag. Now as he said take into consideration that each of the states has its own flag and like he said, why are we expected to know what every flag in the world looks like?
Posted: Mon Sep 27, 2010 1:39 pm
by blind_ex
jezz... It was a joke........
Posted: Mon Sep 27, 2010 3:24 pm
by Eric D
blind_ex wrote:jezz... It was a joke........
I knew it was a joke, and I also think it is funny. I was just trying to make the additional point that Americans should know more flags than the average person out there. Most people think we just have one.
Posted: Mon Sep 27, 2010 4:18 pm
by blind_ex
Eric D wrote:blind_ex wrote:jezz... It was a joke........
I knew it was a joke, and I also think it is funny. I was just trying to make the additional point that Americans should know more flags than the average person out there. Most people think we just have one.
ok I dissagree on that one, well, USA got 1 flag as whole, just because every state got it own flag it doesnt mean that You have to know them all, its like expecting from Brit or Pole to know all crests/emblems of all shires(i dunno wich one is correct - forein here

)..... jezz that would be just insane

Posted: Mon Sep 27, 2010 4:46 pm
by ttocs
ok cool so we do not have to know the state flags now, according to the brit?

Posted: Mon Sep 27, 2010 5:05 pm
by fuzzysnuggleduck
Russia has 83 different "federal subjects" (provinces, territories, etc.). I wonder, they must each have their own flag too, right?
Sweeet M50
Posted: Sun Oct 10, 2010 3:56 am
by Kurt Wild
First of all, a BIG thanks to mhyde for sending me the RCA jack for my M50. Replacing the broken one was very easy and I also replaced the power supply caps with four 16V 4700uF caps. That was easy too.
I had a horrible moment after installing the amp. The sound was SHIT and it cut out immediately whenever I turned up the volume. I was sure my amp was foobar. After a little crying I checked everything and found I had crossed the power and remote cables. The fucker was actually running on the power from the HU remote wire!!
I swapped the wires and OH MY FUCKING GOD IT SOUNDS GOOD! Sounds like an effing cliche but it's like I'm hearing my records for the first time. There's so much detail shooting out the comps the M50 is running I can't believe it. Now I can listen to my heavy metal loud without killing my ears like earlier. Its obvious theres a lot of difference between amps..
Posted: Sun Oct 10, 2010 4:38 am
by mhyde71
nice glad to hear it worked out for you with that rca adapter!
glad i could help!
m
Posted: Sun Oct 10, 2010 10:51 am
by stipud
That power wire looks TIIIINY! You should run 8 or 4 gauge to it!
Nice work on the repair! Congrats on your new baby!

Posted: Sun Oct 10, 2010 9:38 pm
by Kurt Wild
stipud wrote:That power wire looks TIIIINY! You should run 8 or 4 gauge to it!
Nice work on the repair! Congrats on your new baby!

Thanx!
I know, the power wire is 6 square mm, which is between 10 and 9 gauge.
My puny ex amp had a 20 amp fuse and I figured that wire to be adequate. Works fine with M50 too, but its on my upgrade list anyway.
Problem is finding lugs which will accept fatter wire and fit in the M50 terminals. Plan is to add another 6mm wire and stack two lugs onto the terminal like I already did with the grounding wire.
Would you say I may expect to hear a difference after the wire upgrade?
This thing already sounds great and goes loud as hell too! Plus no distortion.