Why did Marantz use 4 capacitors for coupling?

[bleachershane]

Just a quick question I've been meaning to fire off for a while...

Still working now and then with the innards of my CD-63SE and one thing baffled me. I've been wondering why Marantz chose to use 4 Elna Silmic 220uF capacitors for coupling (2 per channel) instead of 1 capacitor per channel?

Surely using 2 per channel:
1: degrades the signal twice over instead of just the usual 1 capacitor per channel
2: costs twice as much to implement at manufacturing stage when 1 capacitor surely would've sufficed?

Totally confused by that decision, perhaps someone can shed some light on it...

I know a good few out there just rip out the DC blocking/coupling caps but I'd rather not go that route so I have a few Nichicon Muse ES 220uF 50V capacitors lying around and so I've decided to take out all 4 Silmics and replace them with 1 Muse per channel. Seem sensible?
Also toying with the idea of putting a Wima Metallized Polyester 1uF 50V across those too, is there any benefit? What is best in the world of film/foil capacitors for this job?

[Thomo]

Hi there. All I know is two caps connected as they are in the Marantz make a bi-polar.

Also, I've yet to find a cd63 that needed them in the first place, and there's no doubt that no cap is best for sound.

If you do still want dc blocking caps in, I recommend using the highest quality film caps that you can, for the least impact on the sound. Bass in particular improves a lot with those Silmics out of the way.

Just my 2p

Cheers, Lee.

[bleachershane]

Thanks for the reply Lee

It's a shame Marantz didn't just put in one bipolar cap if that's what they were trying to achieve. Still at least they've left something for us modders to play about with!

The Muse ES caps are bipolar so I think I'll give them a whirl although I am tempted to try the no cap route, will do a bit more research... What is the effect of DC getting through if there were no DC blocking caps?

[Thomo]

Any DC that gets through to the power amp will be amplified. This is potentially dangerous to amps and speakers.

The chances are that your pre-amp/integrated will have dc blocking on its input anyway.

Having said all that, I've yet to find a cd63 that has a high enough DC output to cause problems. Simply measure the voltage on U210 & U214 - these are the links between the opamp output and the HDAM.

Have you changed the opamps to anything better yet? Or have you just got started on it?

Check out the cd63 mods thread - if you're really new to all this, don't worry everyone on that thread is really helpful. There are a few proper experts on there, such as Brent & Ray + others.

The list posted on this page is a really great place to start.

Hope this helps, Lee.

[bleachershane]

I had a feeling DC getting through would be bad, but my tech minded mate also suggested that the pre-amp I'm using may be have DC blocking on the inputs... if it does, away go the Silmics completely! Will of course do some measurements in to make sure no inherent problems with DC with my CD-63SE.

Had the unit a couple of months, and it's really an ongoing project. By far my favourite CD player I've owned so far.

Done the basics so far, disabled the headphone and muting circuits.
Put in a new clock circuit with it's own transformer (no boutique stuff, cheap eBay kit)
Changed the JRC2114 op amps to LM4562 very recently, not had a chance to break them in yet! Still to disable HDAM and also building 2 new power supply regulator boards for the analogue +12V/-12V to go in. Want to get as much done on my next disassemble (not keen on repeatedly connecting/disconnecting that huge ribbon cable that connects to the front panel!!!)

Considering a full recap next, not sure if it's worth doing, but seeing as the unit is near 15 years old... Deciding what caps to use where (Panasonic FM, Rubycon ZL/ZLH/RX30, etc)

This is indeed the best place and the first place I go to ask for opinions, get advice and info!

How much have you done with your own one?