keflover615
Active Member
Don't know if this amp is vintage or not, just want some info on it, not an ebay question.
Marantz ma-500u thx certified monoblock amplifiers
- Thread starter keflover615
- Start date
signal-dude
Just one good watt.......
I have two of them as my backup amps when I do maintenance or upgrades. They run a little warm but do sound good. Basically they have no sound of their own but that's a good thing. Be aware though if they are more than 4 years old they WILL need a capacitor change job. The pair I bought were described as not working in need of repair or parts.
Very truthful on the seller. Found info at DIYAUDIO by a former audio repairman, changed out the affected caps with Panasonic FC's 105 degree caps and the amps worked fine. They both tested 150 watts into 8 ohms clipping and 200 watts clipping into 4 ohms.
They are not vintage per se but are Home Theatre amps on the high end of things. Don't pass them up cuz' of the cap change out, its an easy job. Takes about an hour each amp.
OBTW, just don't overpay for them, they are constantly on the 'Bay. They ALL need a cap job sooner or later.
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Byrdsmaniac
Active Member
The MA-500 was reviewed in issue 22 of The Audio Critic which is available as free download here:
http://www.theaudiocritic.com/cwo/Back_Issues/
http://www.theaudiocritic.com/cwo/Back_Issues/
signal-dude
Just one good watt.......
Yup, seems the accountants forced them to use El Cheapo Wonton Noodle caps that could not take the heat. Rule of thumb here, after 4 years they are on borrowed time. Like I said the amps run warm, the bad caps affected the self protection mode and the amps would shut down with only a few watts output. Check it out for yourself.
signal-dude
Just one good watt.......
As near as I can tell they were produced somewhere around 1999 onwards. I read somewhere,can't find link,I hate when that happens, that they started to crap out around 2004 or 2005.
Found the repair info on DIYAUDIO.com ,in a thread titled,"Marantz MA500,only 50hz output?" Burnedfingers is the fellow who used to fix these guys. His info fixed my two amps just fine.
I have 4 of these and I think all of them are just fine, all seem to work properly.
I did open one up and visually check the caps in question, and they all "look" fine - no bulging of any kind.
But I'm practicing component replacement, so I'm gonna order up the parts and replace those caps in two of the ma500's.
I'll check the caps I pull and compare the two sets of amps in a system to see if they sound any different.
I did open one up and visually check the caps in question, and they all "look" fine - no bulging of any kind.
But I'm practicing component replacement, so I'm gonna order up the parts and replace those caps in two of the ma500's.
I'll check the caps I pull and compare the two sets of amps in a system to see if they sound any different.
As I mentioned, I've finished replacing those "problem" caps.
As I pulled them out, not one of them tested out of range. Heh, I used my new cheapo transistor tester mentioned in another thread. I'm assuming it's correct.
The biggest issue (possibly) is one of the main 10000uf caps is bulging every so slightly at the top. I looked online and the caps aren't that easy to come by, so I did order some ELNA's. But I still buttoned up the amp for a little testing.
Here's the pic of the cap, can you see the bulge at the top and is that something you'd worry about? I'm a newb but learning.
The amp passed the DB test, and I didn't have to adjust the idle voltage at all, it was spot on.
Amp now playing thru test speakers.
4 more 10000uf ELNA's on the slow boat from China. 6 weeks.:sigh:
As I pulled them out, not one of them tested out of range. Heh, I used my new cheapo transistor tester mentioned in another thread. I'm assuming it's correct.
The biggest issue (possibly) is one of the main 10000uf caps is bulging every so slightly at the top. I looked online and the caps aren't that easy to come by, so I did order some ELNA's. But I still buttoned up the amp for a little testing.
Here's the pic of the cap, can you see the bulge at the top and is that something you'd worry about? I'm a newb but learning.
The amp passed the DB test, and I didn't have to adjust the idle voltage at all, it was spot on.
Amp now playing thru test speakers.
4 more 10000uf ELNA's on the slow boat from China. 6 weeks.:sigh:
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FootFungus
Super Member
Are the originals 30mm or 35mm diameter caps?
Not sure, I'll check when I get home.
OK, so this is what you were trying to point out. But I didn't catch it.
The replacements are slightly bigger around than the originals, and won't fit without modification to the board.
I still wonder if it's worth swapping out, the top is only slightly swollen? Is there like a rule that says
"any swelling at all, replace it"
"minor swelling OK, keep an eye on it"
Advice from the professionals would be welcome.
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restorer-john
Addicted Member
Those replacement ELNAS look fake to me.
restorer-john
Addicted Member
Those caps are 100% fake.
Elna don't make a 10,000uF 71volt LAO cap. Not only that, the labelling is different- they don't say LAO on the the cap- it says 'for audio' above the ELNA badge.
I'd throw them out and buy from a reputable source.
Elna don't make a 10,000uF 71volt LAO cap. Not only that, the labelling is different- they don't say LAO on the the cap- it says 'for audio' above the ELNA badge.
I'd throw them out and buy from a reputable source.
I couldn't find another source. So you mean that I need to find one that looks identical, every word?
I do appreciate the help, I'm still green here but do want to know the details.
EDIT: Yes, I see that ELNA doesn't even list a 71v LAO. Bummer.
So maybe I find the right size in 80v and call it good (get from reputable seller!).
Edit: Can anyone find any 10,000uf (either 71v or 80v) 30mm diameter? Heh, some that aren't fake?
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