DAC buzzes and hisses with Denon DVD3910 but not old DVD player

[HeadSh0T]

I just bought a Denon DVD3910 dvd audio/video, SACD, CD,etc player but it won't work my external DAC.

I can hear some music but it's interspersed with buzzing and hissing when playing regular CDs.

My external DAC uses a CS8414 receiver going into a TDA1541A.

It works fine with my satellite receiver box's digital out and with my older dvd player...

I made sure the denon outputs 2 channel PCM.

The DAC inside the denon is the DSD1796 (24bit 192kHz).

I suspect it's the CS8414 receiver because my friend tried his DAC which also uses a CS8414 (going into TDA1543) and he had the same result...

Any ideas?? Should I change the CS8414 to something else?

[300_baud]

Hi, I'm that other friend what he means by same result is that my dac worked properly whereas his is, as he stated, is having some problem. I'm using Elso's SPDIF input circuit btw.

Mo, I do have a spare CS8414 for you to test if you want (it's already on a browndog).

Take care,
300_baud

edit: I should also add he's using one of the recommended input transformers as listed in one of the crystal PDF files.

[HeadSh0T]

yes that's right i'm using a schott input transformer...

i guess i could try another other cs8414. I didn't think they had such a short life-span..

[Extreme_Boky]

Couple of things to check that just might get you going:

1. Make sure there is no DC going to schroff's primary.
2. Try without pulse transformer; with two 0.01uF coupling caps to CS8414 spdif input and/or ground lift at primary...

Have you used the same interconnect cable when you checked your AND your friend's DAC's?
Maybe you have noisy RF wiring between RCA and PCB...

Good luck!
Extreme_Boky

[HeadSh0T]

Thanks Extreme

1. I just measured the DC from the denon. There's 1mV.

2. I tried using the 0.01uF caps. Same thing.

I listened to it again.. This is what happens. As soon as i plug in the spdif cable, I get about 2 seconds of music then everything just hisses really loudly. I can very faintly hear the music in the background.

[Extreme_Boky]

OK!

you are loosing lock because your impedance matching is off or you have noisy interconnect cable / input wiring. You may have doggy CS chip as well...

Check the attachment to figure DC coupling at primary, and RF coupling at secondary.

Pedja Rogic DAC pages also have a link to diyAudio with the explanation how to rout noise if "simple" 1:1 pulse transformer is used - like in your case - without centre tap at the secondary.

definitely try different interconnect cable...

1mv might be error of the measurement - actually it is because using simple circuit didn’t help (with two caps) - so there's no DC.

That's it - if still no luck, try different CS chip (?)

Good luck
Extreme_Boky

[Extreme_Boky]

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