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Marantz Model 500 converted to all LED's

hadrian333

hadrian333

Active Member
This Model 500 is decked out in all LED's. It uses 6 of the new Northridge Electronics bayonnet AC/DC 6.3V LED's. No soldering necessary and the LED's just fits into the bayonnet sockets and no modification necessary. All the outputs have been replaced with matched pair of Motorola transistors and the speaker relays have been replaced with brand new Tyco power relays. The sound is outstanding!

500.jpg
 
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Very nice....

Beyond the weak output xsters....the meter lamps are almost always an issue too....

Otherwise that is one kick butt amp....

Jk
 
That's a beautiful amp. I'd love to stumble across one of those someday, one of the few vintage amps I really want still.
 
Does it essentially use the same output stage as the 2500 receiver? And would that mod/transistor replacement work in the 2500, assuming the power transformer could keep up?
 
Nope and nope....

mech986 said:
Does it essentially use the same output stage as the 2500 receiver? And would that mod/transistor replacement work in the 2500, assuming the power transformer could keep up?
Click to expand...


The output stage on the 2500 is a stacked power stage....different design and not as on the edge as the 500. The matching of the transistors is good idea but time consuming step, that is less needed with today's transistors. Still a good idea if you have the time or $ to spend.... I matched mine within 5%.

The 500s output transistors were an earlier design that were compromised by the need to supply the military with parts at the time... Actually Marantz had service notice that specified using the transistors from from the 510. (if I have that right). Simply because the manufacture of those transistors could provide the quality required as it was not involved in the cold war... The original transistor manufacture was sending everything it could to the military and leftovers for the consumer market.

The transformer on the 500 is a 2.2kva monster... That allows it to double down at 600wpc into 4 ohms. The 2500's transformer would likely melt at that level.... Without the protection circuits, the 500 would likely be capable of 800wpc for a short peak.... But I would never attempt that on test loads or speakers.... Way too risky for my taste... My test loads are only good for 250w and they are like toaster ovens at that point...


Jk
 
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Looks good...
I know its a long shot but (fingers crossed).. If anyone has a spare front door/lid for their 500 I would be more than happy to buy it off of them?

Something tells me that it could be a very loooong time until I find a spare door.lol:no:
 
RPMz said:
Looks good...
I know its a long shot but (fingers crossed).. If anyone has a spare front door/lid for their 500 I would be more than happy to buy it off of them?

Something tells me that it could be a very loooong time until I find a spare door.lol:no:
Click to expand...

... join the club...:no:
 
jstang said:
Ok I'll bite. Where you did get the bulbs....?

Jk
Click to expand...

I've just put the same LEDs in my 2252B and they look absolutely amazing! The lamps are manufactured and marketed on Ebay by Northridge Electronics: http://stores.ebay.com/Northridge-Electronics?_trksid=p2047675.l2563. The lamps are very well made and look like an OEM piece.

My 2252B is about as minty as they come and the diffuser paper was like new, no discoloration whatsoever. Prior to installing the LEDs I "thought" the display was blue, but after installing them the display really WAS blue. Seeing the LED lamp vs the factory incandescent it's clear that the yellowish glow from the factory lamps prevents the true blue color of the dial to shine through.

I cannot praise the look of these lamps enough. The dial went from a pale, greenish, blue to a brilliant, almost neon royal blue. It does not look overly bright or garish in any way. I tried to take a side-by-side photo of the two tuning meters, one with the LED and one with the factory lamps to show the difference but my camera could not deliver a decent low-light shot. It is by far one of the best "bang for the buck" upgrades I've ever done and I also have the piece of mind that the mint diffuser paper will not get yellowed by the heat from the OEM lamps. Not sure if the effect will be as dramatic on the receivers with the black plastic tuning dials, but on my aluminum faceplate, it is spectacular. Highly recommended! :thmbsp:
 
Those are not the bayonet lamps mentioned by original poster....having stock like plug in lamps is way to go for me.

Jk
 
Nice product....most likely will go for them. But I don't think the 500 is a green amp at 120w idle power before or after LEDs...:D.
 
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