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Marantz 2500 Refurb

Thanks marantzfan!

All is well spec-wise with the 2500. Tone controls have the proper range, preamp noise level below -90dBv on both channels and .06% and .08% THD+N. The frequency response sweep is well matched between channels. The sweep of freq response, THD and phase with the tone controls set to "OUT" and "IN" are enough different that I knew they were different but REALLY dang close. All those polypropylene caps in the tone control circuit makes that possible I believe. I already could not detect any difference in listening tests.

The power amps make 295W/297W at clipping, both channels driven into 8 ohm loads so plenty of headroom there. THD+N at 125W is .04%/.06% and at 1 watt is .175%/.234%. The higher distrotin at 1 watt doesn't surprise me as this beast has a ton of gain available so has a high noise level. So the error percentage is more indicative of noise. The noise level is -46.8dBV/-46.2dBV but relative to 250W is -85.6dB/-85.0dB.

In summary I believe it to be just fine. This is not the receiver for listening to classical music at very low levels! Even at a 1 watt type of level it sounds great though. Pretty neutral tonally considering the sound of the early 70's units such as the 2230/2245/2270 ones. It's not so sterile it becomes tiring to listen to. I have not heard a cleaner FM sound from anything, it's almost like listening to a CD or record directly.

I'm so glad the saga is finally over and I'm very thankful for the comments, assistance and encouragement from all. Special thanks to Tom AKA Catrafter for his kind posts. I hope this thread will be of help to future rebuilds. Feel free to PM me with questions if you're a brave soul who takes one of these on! :thmbsp:
 
Two other notes come to mind.

The "peak" LEDs come on at about 280 watts and are very even with each other.

The scope display for the FM tuning functions is centered a bit to the right and there's no adjustment for that. When the multipath is optimized looking it and the center tuning is at the right hash mark, about 1cm to the right of center. I wasn't sure if that was normal, never having come upon a scoped unit before. Anyone know about that?

EDIT: I found the pot. It is on the "RR50" board as pot RR52 (2.2K). That board attaches to the back right end of the "switches circuit board" PS01 on jack PS06. That would tback and right as viewed from the receiver front and top. It will center the FM functions' scope display. That adjustment is NOT in the manual.
 
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Almost forgot to post a picture of all of the parts replaced.
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Nicely done refurbishment!

I think you should post the total number of hours you spent on this project and the total cost in parts. Just to give other non-technical members a real world idea of how much real effort goes into this type of work.
 
Thanks for that compliment! I'd like to say I'm going to miss working on the 2500, but I'm sure NOT! :D

I'm playing with a Kenwood that had a bad photo cell / LDR part, converting it to LED. Kind of fun for a switch! I was in the midst of a 4400 refurb last year when I had to dismantle the shop that I'll be picking up on after this one, perhaps I'll start a thread on that one. :dunno:
 
ChrisMarantz said:
Nicely done refurbishment!

I think you should post the total number of hours you spent on this project and the total cost in parts. Just to give other non-technical members a real world idea of how much real effort goes into this type of work.
Click to expand...

Thanks Chris! I didn't track the number of hours but I would rough guess it at 60-80 maybe, about 4 times as long as a 2270 say. I didn't charge near enough for the labor as it didn't look as hard as it was. The parts cost charged was just over $255.
 
rBuckner said:
I was in the midst of a 4400 refurb last year when I had to dismantle the shop that I'll be picking up on after this one, perhaps I'll start a thread on that one. :dunno:
Click to expand...

I'm doing one right now, 3/4 of the way through- I'd be happy not to do another, 4400's are a bear to work on.
 
Just now seeing this thread.

Damn, man, that's one hell of a job! Who ended up buying that lovely machine?

Hope your dog is pain-free. He looks like my own dog, with that cute, older-dog smile. Tom T Hall was right about old dogs (children, and watermelon wine).
 
onwardjames said:
Just now seeing this thread.

Damn, man, that's one hell of a job! Who ended up buying that lovely machine?

Hope your dog is pain-free. He looks like my own dog, with that cute, older-dog smile. Tom T Hall was right about old dogs (children, and watermelon wine).
Click to expand...

Thanks! It went to a guy in PA. I need to find out if he's an AKer but he never mentioned that.

Sarge seems to hardly notice I think, he's doiung very well - thx for your well wishes. Great quote too! :thmbsp:
 
The tragedy of loving a dog is that in the normal scheme of things, they will go before we do.

Glad he's doing well, considering. Love him all you can, and see him thru.

If I could trust the shipping monkeys, I'd love to have you go over some of my broken gear. I'm about to drive 5 hours to see Mattsd for a rebuild on a SX1250 just to ensure it arrives safe. Once done, I'll probably drive back to get it.

Your work on that was amazing. SO many great techs here, alas I am not one.
 
@ onward: Thanks for your kind comments! Ole Sarge gets lots of love for sure, he's laying beside me as I type. I hear ya on the shipping and the cost! The 2500 sold and is off to Pennsylvania, it cost almost $80. One thing I did was to cut two 3/4" pieces of plywood, one for the bottom and one right over the receiver top. First it was bagged and got two layers of large bubble wrap. Solid styrofoam was placed inside the plywood to take up all space. An additional 1-1/2" piece was on top to take up space. We'll see!

@ bk: I think patfont's cap shootout thread has quite a bit more? And..ugh...have to offer congrats to the Canadian's men's hockey team on shutting us/USA out in the semi's. :D
 
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