Need any info on Phoenix Gold M50

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The only info I have is that you should give it to me 🙂. Just kidding, they are very cool amps. I've never owned one but have heard good things about them and I like the way they're designed on the inside. I did own one of the smaller fan cooled zx amps and it sounded very nice.

Pretty sure your amp can run 1 ohm loads in stereo or 2 ohms bridged with good airflow/ fan cooling. I think the specs are 25 x 2 into 4 ohms, 50 x 2 into 2 ohms and 100 x 2 into 1 ohm. They usually put out more than they're rated so I'd guess around 275-300 rms when totally loaded down. I'm actually thinking of selling my ppi a600.2 amps and getting two phoenix gold m amps but I'm so loyal to ppi, they've never let me down and sound so good.
 
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A lot of the PG amps of that era had problems with leaking capacitors that could do extensive damage. The damage wasn't always visible until the caps were removed. If you're going to buy one that hasn't been recapped before significant damage was done, it may be difficult to repair.
 
Morning all, the M-50 is a sweet little amp. So what info are you looking for ?

PG typically does not release documents, but I have e bunch of years looking at these and others, perhaps I can help... Lets talk some soon...🙂


Addendum: leaky caps are typical for these since they are from the mid 90's. If not taken care of the electrolyte leaks onto the board and shorts across the gold plated board and can cause the board to actually burn up. The simple fix is to replace them and to use RTV on their bottoms to prevent the electrolyte from shorting across the leads and board. PG used high grade caps made by Panasonic, but after 10 or 15 years of service and tons of vibration on the leads they leak at the leads onto the board. Pretty common repair issue for older PG amps.
PG used double sided boards and the board could be damaged on both sides if the liquid leaked through to the bottom side. Most of the time the corrosive damage was kept to the top side where 12 volts was allowed to pass through the liquid and across the board area. The 12 volts seems to aggravate the corrosion and the copper plate underneath the gold would dissolve in a very green manner, and then the gold plate would just lift off the board. No traces left no circuitry either. I have seen the PC board literally burn black to carbon and then its board repair time...
 
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Stupid leaking capacitors have been the bane of my existance in IT as well.

Let me guess it is the nichicon's on the far right near the transformer and heatsink that leak. If this amp is from the late 90s to early 2000s that would make perfect sense.

If it is the large panny's (actually matsushita's but whatever) in the middle, that would be the first time I have seen panny's fail.
 
The 16 volt Panasonic's near the toroid are the usual culprits. 2200 ufd at 16 VDC. PG used high grade caps, They just fail on the 12volt side commonly in all early models. I like to use 35 VDC replacements and RTV dam the leads to prevent electrolyte shorting. Its the shorting of the 12 volt rails that does the bad deed and damages the card so badly.
PG was the first to use high grade 105C rated caps back in the 90's. I guess that is why they lasted 12 to 15 years before they failed. That is a long service life for any cap.
I use either Panasonic or Nichicon as replacements, I just add the RTV as a preventative measure to protect the board and glue down the cap so it does not pull on the leads so much, and prevent electrolyte from shorting across the board. < the latter causes the board traces to lift and worse case literally burn to carbon the fiberglass epoxy board...

PG usually used Nippon Chemicon for the large rail caps, and their typical replacements were always Chemicon brand. Nothing but high grade Japanese made caps inside of these amps.
 
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The attached images show the damage in an Autotek amp (the damage is similar to that in the PG amps). You can see that virtually all of the damaged area is within the outline of the cap which can make it difficult to see with the cap in place. The second image shows that the electrolyte has actually penetrated the circuit board. When it does this, the board becomes conductive (as was previously stated). If there are power and ground traces on opposite sides of the board where it's conductive, the board will burn and can leave very large holes. Often there will be very little smoke or odor when the board burns like this. It won't blow the fuse and many times, the user will have no idea that it happened until the amp quits.

Although I'm not a fan of recapping amps without seeing failed caps, if anyone owns an old Autotek (or their close cousins, Hifonics, etc.) or PG amp that they value, they should have them checked. If they use the Nichicon PL or PF caps, they should be replaced. Even if the amp isn't being used, the Nichicon PL and PF caps should be removed because they will damage the board whether power is applied or not.
 

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Great pics, thx Perry



Oh a simple test method:

take a piece of stiff clean paper and slip it under each cap. If after it has been withdrawn from under the cap it appear wet or discolored in any way, you have leaking caps. replacement is pretty much mandatory at this point....hope this helps some....
 
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Yeah, it appears they used both Nichicons (HE models from the pics I have seen) and Panny's on the side with big matsushitas in the center.

Interesting that they don't bulge and instead push out the bung (yeah that is actually the name for the rubber/plastic insert on the bottom of a capacitor).

Either way, that is some nasty damage. Rarely see that bad in IT even with catastrophic cap failures.
 
Electrolytics are a weak point in any equipment more than 10 years old so it's good practice to replace them.

Genesis Series 2 amps used Rubycon YXB caps and the smaller cans also leak, fortunately they are fed via resistors which limit the damage to the board.

Had an amp in recently where some 18mm diameter parts had also dribbled, caused quite an impressive arc on power up.

The Low ESR electrolytes used by Japanese cap manufacturers in the early 90's seem to have had long term compatibility issues with the seals being used, eventually the seals no longer seal and conductive liquid gets onto the board causing serious corrosion and / or arcing.
 
Electrolytics are a weak point in any equipment more than 10 years old so it's good practice to replace them.

Genesis Series 2 amps used Rubycon YXB caps and the smaller cans also leak, fortunately they are fed via resistors which limit the damage to the board.

Had an amp in recently where some 18mm diameter parts had also dribbled, caused quite an impressive arc on power up.

The Low ESR electrolytes used by Japanese cap manufacturers in the early 90's seem to have had long term compatibility issues with the seals being used, eventually the seals no longer seal and conductive liquid gets onto the board causing serious corrosion and / or arcing.


Here again your dead on about this issue. I also tell folks to apply a small dam barrier of RTV across the bottom of all new caps so when they do leak they are not dead shorted underneath. The RTV dam will block direct shorting for a while, and increase any mean pathway of any short that does appear with time. The longer the pathway the less current it will carry and the less damage it will cause to the board in the long run...hope this helps some..🙂
 
Sorry to have brought up an old thread but i just acquired a PG M50 amp. I just replaced all the caps with Chemicon and Pana FCs. Used RTV across the bottom of all the new caps. I turned it on and found the left channel is giving out about 3.3V DC.

Anyone have a schematic or service manual for the M50 that will help me in getting it fixed?

Thanks.
 
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