I have boxed in the Duelund output capacitors underneath the player . There isn't enough room to fit them inside . To access underneath I simply need to unscrew the box section .the caps are affixed to the inside of box with double sided tape with some insulation over the caps and on the cd base plate.
None of this can be seen unless your eyesight is level with the underneath of the player .
This will be improved once modding is finnished with better and shorter wire and neater insulation .
I cut a small slot in the baseplate for the wires so the base plate can be removed without unsoldering wires .
The wires tuck in neatly to the space at the end of the box once fitted .
The box was the lid part of an electronic box from Jaycar . Perfect for this application .
Wow - you have done a lot of work. I wish we could have spoken earlier - read on.
With a 2 DAC / differential to single ended arrangement such as the 94MKII, the output circuit can be direct coupled with no caps required.
This is always the best way to go if possible - it saves money and no cap is better than any cap in signal path - even Duelunds.
However the circuit needs to be a proper DIF -> SE design and it needs a small trimpot to null any offset at OP. This can be done pretty simply with 3 opamps.
The standard circuit uses 5 opamps per channel and is pretty complex. This is mainly because it incorporates Fet switched de emphasis which you don't need.
The opamps should be biased into class A - but the right amount needs to be tweaked.
The standard regulators are either 317 or 78xx type which don't filter or block rubbish coming from other parts of the player above a few kHz very well.
Once you get to 100's of kHz they almost stop working all together. This is one reason why your PS cap changes make so much difference, they are
doing most of the filtering work of the regs.
For regulators I use very simple discrete series pass or shunt are even better. These regs work right up into the MHz range at filtering incoming rubbish.
They also have much lower noise than 317 / 78xx regs - but I'm not totally convinced the random noise is a big issue.
It's also best to use separate regs for R and L channel.
All this can be made on a relatively small ground plane covered board with room for caps, resistors and with opamp sockets.
The baseline performance is a long way above what the standard CD94 gives you.
Then it's a case of tweaking resistor and cap types, opamp types and amount of class A bias to get everything sounding best or to your taste.
T