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Second thing, behind the RCA jacks, resistors R102 & R202 have been replaced by second order RC-networks.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.
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
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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!
Last edited by stipud on Wed Sep 22, 2010 8:09 am, edited 1 time in total.
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.
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.
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.
Check my buyer/seller ratings http://phoenixphorum.com/gridracer-vt4548.html
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??
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??
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??
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.
Got "schooled" by member shawn k on May 10th, 2011...
No longer really "in tune" with the audio industry, and probably have not been for some time.
Hands down the forum's most ignorant member...
Don't even know what Ohm's law is...
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?
what else can I say I am a grumpy asshole most of the time.
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.
Got "schooled" by member shawn k on May 10th, 2011...
No longer really "in tune" with the audio industry, and probably have not been for some time.
Hands down the forum's most ignorant member...
Don't even know what Ohm's law is...
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
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..
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.
