Philips CD304Mk2 dig. out sibilance

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PetrL

Member
2005-09-27 8:35 am
Hi,

recently I bought Philips CD304 Mk2 as transport for my nos DAC. Before I used different Philipses with CDM2 or 4 and was quite satisfied. But the 304's low level detail is unbelievable, probably thanks to the CDM1 transport. The first time the soundstage is as good as from record player!

However there is sibilance mainly on leading Ss in vocals, some instruments may also sound more aggressive. Unfortunately I can't tolerate this kind of distortion. I tried to fiddle (in both directions) on load of pin 14 SAA7220 by changing the first resistor of voltage divider to which the digital trafo is connected. Then I connected the whole divider+trafo via capacitor. But no succes.

Now I don't know what to do next. Replace crapy wire, including 2 connectors, from PCB to RCA connector? Change SAA7220 from another player? Buy another CDM1 player and keep this one as spare? Any ideas?

Petr
 

PetrL

Member
2005-09-27 8:35 am
Well, yesterday I checked the supply voltage of SAA7220 and found only 4.36V, with all drop from 5.01V on the 4R7 resistor just before decoupling capacitors, so the Philips must have intended so (?). This also gives lower consumption than the datasheet's 180 mA. Anyway, in other player I measured 4.8V and decided to short the 4R7. The difference is not night and day, but I think the sibilance decreased to more or less acceptable.

Later I'm going to replace the resistor by a choke, maybe change to SAA7220P/B, and build new dig. output per Katapum schematics here.
 
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