Very low level noise on CD880

tubee · 23rd November 2008, 01:10 PM

I modded a cd 880 with kwak clock 7, reclock to dac (5.8Mhz) and dem reclock. Replaced lytics with sanyo oscons near dig chips and dac. Also exchanged 6 dividercaps 3 per channel from 0.1 to 1 uF MSB, 1uF the one after, and 0.47 the next. Rest kept 0.1 uF.

When playing music i hear very faintly a sort of lispeling noise (like a FM tuner) around low level music. In special when bass tones come in.

The separate IV/buffer pcb (a professional mod) is above the dac, connected with non shielded cable from dac. When i turn and move this pcb no change of low level noise.

I changed dem again to a cap, no change. So must be the divider caps or chip decoupling.

Anyone a suggestion what this could cause?

tubee · 24th November 2008, 11:26 PM

Scoped around: Without clock: Gnd is allmost quiet, as good as.

With clock: 100mV of clock remains and spikes on the gnd screen. Horrible. Tried different gnd of kwak spots, no difference.

Will try a tent clock and if possible on separate x former, choked, and see if it can be canned.

A simple magnavox player was used to compare, that one is allmost silence. Must say the dem pins shows a lot better signal on the cd880 with dem reclock. But 100 mV noise.....

I previously modded a cd304mk2, wherein the kwak could get a nice separate place inbewteen cast aluminium. There i had no problems.

23rd November 2008, 01:10 PM	#1
tubee diyAudio Member Join Date: Jul 2004 Location: Netherlands	Very low level noise on CD880 I modded a cd 880 with kwak clock 7, reclock to dac (5.8Mhz) and dem reclock. Replaced lytics with sanyo oscons near dig chips and dac. Also exchanged 6 dividercaps 3 per channel from 0.1 to 1 uF MSB, 1uF the one after, and 0.47 the next. Rest kept 0.1 uF. When playing music i hear very faintly a sort of lispeling noise (like a FM tuner) around low level music. In special when bass tones come in. The separate IV/buffer pcb (a professional mod) is above the dac, connected with non shielded cable from dac. When i turn and move this pcb no change of low level noise. I changed dem again to a cap, no change. So must be the divider caps or chip decoupling. Anyone a suggestion what this could cause?

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24th November 2008, 11:26 PM	#2
tubee diyAudio Member Join Date: Jul 2004 Location: Netherlands	Scoped around: Without clock: Gnd is allmost quiet, as good as. With clock: 100mV of clock remains and spikes on the gnd screen. Horrible. Tried different gnd of kwak spots, no difference. Will try a tent clock and if possible on separate x former, choked, and see if it can be canned. A simple magnavox player was used to compare, that one is allmost silence. Must say the dem pins shows a lot better signal on the cd880 with dem reclock. But 100 mV noise..... I previously modded a cd304mk2, wherein the kwak could get a nice separate place inbewteen cast aluminium. There i had no problems.

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