Marantz ma-500u thx certified monoblock amplifiers

Dingman · Aug 29, 2014

And as a side note, I just finished with the re-cap of "unit 03" (I have 4 of them).

The CN and C caps that I changed tested out pretty bad. The 100uf measured down around 40 and the 10uf were also quite low@ 6uf with high ESR of about 20. I measured the new caps going in and for the most part, they were far better at proper values with under 1 ohm ESR.

Again, I'm a bit green here but the original caps seem to measure out with high Vloss, high ESR and over 35% error.

If I get bored, I'll re-measure and document it all, for future reference.

EDIT: based on the measurements of the original caps in the gain and protection circuits, I decided to change out some of the caps in the signal circuit - these originals didn't measure so badly compared to the Nichion's I put in their place. Only did the 3 larger caps in the signal circuit.

Dingman · Aug 30, 2014

I should maybe create my own thread, eh?

Well, get this~ on Unit 02, we have:

Blue ELNA for audio filter caps, same values.

BOTH are bulging ever so slightly at the top. In unit 03, it was only one cap. Are we having fun yet?

Dingman · Aug 30, 2014

if they didn't have these things crammed in so close together, I could use a 35 mm, but 35mm won't fit without board mod.

Dingman · Aug 30, 2014

The caps removed from my "unit 02" measured out much better than a previous unit.

After the re-cap, I forgot to take pics until after I remounted the heat sink - oh well.

ivandezande · Aug 30, 2014

http://www.nichicon.co.jp/english/products/pdfs/e-ks.pdf

Here's some if you could step down to 8,200uF. Good luck finding them in stock however, I need some as well and there are absolutely no other 71V 30mm caps that uF go up that high and are made for audio. let me know if you find a solution, cause I sure can't other than buying the min. order of 123 of them!

Dingman · Aug 30, 2014

For me, I think the solution will be drilling out new holes in the board, looks like there is enough room for that.

mhedges · Sep 6, 2014

Dingman said:
For me, I think the solution will be drilling out new holes in the board, looks like there is enough room for that.

I'd use 105C rated Panasonic caps as mentioned earlier in the thread.

Dingman · Sep 20, 2014

mhedges said:
I'd use 105C rated Panasonic caps as mentioned earlier in the thread.

Thanks, and yes, the problem caps were replaced with higher voltage\temp rating than the originals (errr, most of them were higher rated, a couple were the same rating but quality caps).

I still have no solution for the 10,000uf rated caps. So, these amps have been removed from the system for now.

Dingman · Nov 5, 2015

Forgot to update~ I installed the fake caps. They tested OK, so I used them. But the amps have no life, sound sterile and still are not being used more than just occasionally.

amaraenzo · Jan 12, 2017

Dingman said:
Forgot to update~ I installed the fake caps. They tested OK, so I used them. But the amps have no life, sound sterile and still are not being used more than just occasionally.

Hi there, I recently bought two Ma500 and after reading this thread and the one on DIYAudio, I am thinking about replacing the 6 caps mentioned in the other thread. I was just wondering how your "cheaper" caps held up since 2015 and where you got them from. I can't seem to find much info on them...
Also, I have not received my MA500's yet so I'm sure I'll find out more on them once I have the amps and caps sitting in front of me!

Thanks for any comments you can make!

Dingman · Jan 12, 2017

Well, I haven't really used the amps much. The fake ELNA's haven't blown but I haven't opened them back up to look for bulging or anything.

I got the caps from the bay, I can find the seller if you wish, but I'd find other caps, just because.

amaraenzo · Jan 13, 2017

Thanks Dingman. I'll do some research on my own and try to find the caps myself!

tarior · Jan 13, 2017

Since someone else revived this old thread, I'll thow in my $.02. There was nothing wrong with your original Elna filter caps. The "bulging" on the top of the cap is just a plastic disc that has a little bit of a dome shape to it.
As an aside, Mouser and Digi-Key have 10000uF 71V (or higher, 80V or 100V work just fine) caps out the wazoo. Don't buy anything on ebay unless you are knowledgeable enough to be sure that you aren't buying counterfeit product.

amaraenzo · Jan 13, 2017

tarior said:
Since someone else revived this old thread, I'll thow in my $.02. There was nothing wrong with your original Elna filter caps. The "bulging" on the top of the cap is just a plastic disc that has a little bit of a dome shape to it.
As an aside, Mouser and Digi-Key have 10000uF 71V (or higher, 80V or 100V work just fine) caps out the wazoo. Don't buy anything on ebay unless you are knowledgeable enough to be sure that you aren't buying counterfeit product.

Thanks Tarior. Being completely knew to buying my own capacitors and other components, I had been looking at where to source them from. Thanks for recommending those two sites.
Digi-Key has 70v or 75v. What would 80v or 100v mean should I decide to go that route instead of 70v? I understand the difference in the two caps, I'm wondering what it'd mean as far as output, change sound quality, make the amp run harder etc etc... As I said, I'm not super knowledgeable, but willing to learn so any advice or comments are super welcome!

tarior · Jan 13, 2017

When it comes to voltage ratings on capacitors, you can always go up, but never down, and in an unregulated power supply, that also applies to the capacitance value. The difference in sound between an 80V cap and 100V is absolutely nil.

amaraenzo · Jan 13, 2017

Got it thanks! At least it gives me more options now since I don't need to buy 400 of one cap... I can always look and see if they have singles at different voltage ratings

tarior · Jan 13, 2017

You will find 80V and 100V capacitors to be far more common and usually less expensive than 70V and 75V.

amaraenzo · Jan 13, 2017

awesome thanks for the info!

hildebrau · Jan 24, 2018

I have 5 of these MA500's that I need to fix up. I'm terrible at soldering; but I've bought a new soldering iron and really don't have much to lose at this point. I pieced together the schematic drawings. Now I just need to know which caps to order. Can someone put together a suggest list of SKUs from mouser.com? I don't have much confidence in myself to order the most appropriate thing.

I took one apart last night and I'm trying to "amp" myself up to do this. Photos: https://photos.app.goo.gl/zXjp6CBVQpfWI26l2

I have the following in a Google Sheet that is editable (today). I encourage you to add in the appropriate SKU's.

Board ID Original Label Suggested Other label info Mouser SKU
C701 4.7µF / 50v ELNA, CE 105°C, 9805
C705 100µF / 16v ELNA 9810, CE 85°C
C710 33µF / 100v ELNA, CE 85°C, 9814
CN01 22µF / 16v 85 °C, 9805, ELNA
CN02 47µF / 16v ELNA, 9802, CE85°C
CN03 47µF / 16v 9802, CE85 °C, ELNA
CN05 2.2µF / 50v 2.2µF / 100v M +85°C, blue

Thank you!

Marantz ma-500u thx certified monoblock amplifiers

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