I believe you need to find out by applying the filter first and foremost on the BD side, it is the source of the noise.
Yes, SMPS can be very noisy very high up in frequency tens and even hundreds of MHz even if switching frequency is in the kHz region.
But also the digital electronics can be quite noisy too, I have an old CD player with an old style mains transformer PSU and yet very noisy.
You need to find CM beads and small ceramic capacitors for your work, and they all have to be soldered as close as possible to the signal post, not like the red and green caps you have several cm/inches away on that breadboard.
Are the phono connectors on the BD side fully isolated or grounded in the chassis?
Maiko,
The Marantz UD7007 has a separate, dedicated SMPS supply board supplying +/-12VDC, +12VM, +5V with the outputs placed on the same ribbon cable connector. The board is a 2 layer board with all the power supply grounds connected to the some small copper ground plane, and the ground plan is directly placed on the chassis. I expect that the ground noise is terrible and the ground noise is directly connected to the chassis.
Ironically, the analogue power supply ground wire along with the +/-12V analogue power supply wires connects the ground to the DAC board, and right at the end of the DAC board at the RCA signal output, the RCA socket is connected to the chassis. So there are apparently 2 ground paths from the power supply board to the RCA of the analogue board.
Isn't this a design error?
The Marantz UD7007 has a separate, dedicated SMPS supply board supplying +/-12VDC, +12VM, +5V with the outputs placed on the same ribbon cable connector. The board is a 2 layer board with all the power supply grounds connected to the some small copper ground plane, and the ground plan is directly placed on the chassis. I expect that the ground noise is terrible and the ground noise is directly connected to the chassis.
Ironically, the analogue power supply ground wire along with the +/-12V analogue power supply wires connects the ground to the DAC board, and right at the end of the DAC board at the RCA signal output, the RCA socket is connected to the chassis. So there are apparently 2 ground paths from the power supply board to the RCA of the analogue board.
Isn't this a design error?
Indeed!
I've had to isolate:
- The computer
- The USB connection (computer direct to DAC)
- The TV
to seriously improve my audio (NB: the situation probably wasn't being helped by the iMac also connected to the TV via HDMI TV-side).
From there, I also had the idea to use a DIY power cord that I was using for my SS amp on my 4K Blu-Ray player, and then I also tried plugging this into my DIY AC Filter box (it does have chokes), and I then obtained a radical enhancement in PQ as well!
These are what I have been dealing with:
- Clean AC (as the SMPSes greatly pollute the mains, the Linear Reg PSU does also but to a much, much less extent),
- Ground plain pollution - re-worked what constitutes a proper USB connection from the computer to the DAC to deal with this
- VBus -> injecting clean power to the DAC
- Leakage Currents - dealt with one path-way through the new USB connection
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RCA itself is a design error...
I wouldn't be surprised if you found other avenues for Leakage Currents, Shield-Current induced noise and Ground plane noise and other things taken for granted but which are significantly bad for audio.
Follow the continuity from one device's ground plane, ground pin, to the output jack, to the shield then do the same to the other side...
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