Marantz CD63 & CD67 mods list

I'm going to leave the 7220 in place for now, I don't want to take too many steps at once. I've read that the filter can bring good things, IF the supply-decoupling is o.k. So i'll have to experiment with that later. It's placed in a socket for now, so bypassing it is very simple.

It's not difficult to do some reclocking with the 63/67 DAC, I wonder if it would be equally beneficial with a delta-sigma DAC.

Ray
 
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I have by-passed the hdam circuits, upgraded the op-amps and fitted a low jitter clock. I was reading an earlier post regarding the dc blocking caps. Marantz use two electrolitics back to back. Firstly, can I replace these say with a wima 4.7uf non-polorised and secondly can I connect them directly to new rca,s, therefore bypassing the muting circuits? Is it neccessary to remove the supply for the muting? I'm not a techy so be gentle with me!
 
Thanks for that Simon. The first time I by-passed the hdam circuit was when you did way back in January 2006 when the thread started. I think with the op-amp upgrade this is a very noticable mod. Iv'e modded several since then but iv'e never got round to the dc blocking caps. I'm a little scarred of lifting them completely. What caps and value would you suggest and do you think it worthwhile by-passing the muting circuit?
 
I'd always bypass the muting circuit because it's a free tweak and some people have heard a difference doing so. I've never noticed much of a noise issue after removing muting.

In a player running op-amps I'd be inclined to remove the DC blocking caps completely (or jumper them out/bypass with wire etc. It's a good idea to check the DC levels on the output (whilst on but not playing music, using a multimeter set to DC volts). If the voltage is in the tens of millivolts ie. about 0.05V or less I'd not worry about it. The thing is, almost all equipment down the line (amp or preamp) will have a capacitor or other measures to deal with incoming DC. If you have a DC-coupled amp and expensive speakers then obviously you don't want to do this as it could damage your speakers.

If you must have a cap in there then of ones I've personally heard I'd not hesitate to recommend Mundorf MKP, Clarity Cap SA or Mundorf Supreme in order of increasing price and sound quality. Go for 4.7uF.

Simon
 
I have another question which I don't think has been covered in this almighty thread. I know the cd63 uses the same vam1201/2 as the cd67 but can the whole unit be interchanged? The reason I ask is that I have noticed that the cd67 has an ic on the control board underneith the laser assy, whereas the cd63 uses transistors mounted on the side of the board. I would appreciate any help with this question.