This is my current setup. So anyone trying to modify his Sony ES player from ~1991 to 1994 (previous of Sonys current pulse generation starting with XA50ES) can extract all relevant information from the attached picture
The Zapfilter is really a fantastic sound improvement and highly recommended (apart from a low jitter clock).
The Zapfilter is really a fantastic sound improvement and highly recommended (apart from a low jitter clock).
Attachments
I haven't had a chance to measure the voltages yet by the way.
I'm guessing PLM is probably pulse length modulation. Probably Sony-ese for PWM (pulse width modulation).
I don't think this block diagram alone tells you anything about what ultrasonic crap comes out of the DAC.
The NPC SM5872BS DAC chip in my player has absolutely no analogue filtering built in, and the gentle filtering if the Zap is not enough for the raw PWM coming out - you get noise with the music. This is quite unusual though. It will probably be OK.
You need to know if the DAC is voltage or current output though as you have to configure the Zapfilter accordingly.
I'm guessing PLM is probably pulse length modulation. Probably Sony-ese for PWM (pulse width modulation).
I don't think this block diagram alone tells you anything about what ultrasonic crap comes out of the DAC.
The NPC SM5872BS DAC chip in my player has absolutely no analogue filtering built in, and the gentle filtering if the Zap is not enough for the raw PWM coming out - you get noise with the music. This is quite unusual though. It will probably be OK.
You need to know if the DAC is voltage or current output though as you have to configure the Zapfilter accordingly.
Glenn2 said:
Thanks glenn ;D You mention the RC lowpass filter after the DAC. Since I made the Zapfilter mod some time ago (when I didn't have that much knowledge, learning by doing
I've also upgraded R501,R502,R503 and R504 resistors in the HF signal path with Vishay CMF55 non-magnetic Rs. This resulted can easily be heard: more details in the sound reproduction, esp. in the higher registers.Now the only stock parts left in the signal path between DAC and Zapfilter are C510 and C410 - these are small blue film caps with 470pF value. But.. I've learnt that for high frequency applications there are better suited cap types. Ie Polystrene (best?) and Silver MICA (second best?) with the appropiate values.
What would be best? I think the polystrene but I do not know a source where to buy them. For MICA I've found http://www.thel-audioworld.de/bauteile/glimmer/glimmer.htm but some say they add a "metallic sprinkle" all over the sound. But I am searching for a little bit more smoothness. Would it be good to double the value from 470pF to 1nF, then the corner frequency would be 18095Hz with the 6dB/oct (?) rolloff. With 470pF it is 38500Hz..
Oohh... The ZAPFilter.... Know that one. Both mk1 and mk2. These are a great improvement over most op-amps. BUT!! The ZAPFilter has one huge problem: Single ended output sounds just like single ended!
When you compare with similiar PP output based analog stages, you will be amazed! The improvement is in the same range as going from op-amp to ZAPFilter.
I never really understood why LC choose the single ended output. Anything else from LC is PP. Really strange, especially knowing the limits om Single Ended outputs.
When you compare with similiar PP output based analog stages, you will be amazed! The improvement is in the same range as going from op-amp to ZAPFilter.
I never really understood why LC choose the single ended output. Anything else from LC is PP. Really strange, especially knowing the limits om Single Ended outputs.
Hurtig
I have come to the knowledge,
LC Audio is currently under forced administration/closure.
http://www.cvr.dk/Site/Forms/PublicService/DisplayCompany.aspx?cvrnr=26556732
I wonder why
and people beware!
That useall means that the firm are now past!
dispite there site is up and running, if people order somthing the money is most likely gone forever
I have come to the knowledge,
LC Audio is currently under forced administration/closure.
http://www.cvr.dk/Site/Forms/PublicService/DisplayCompany.aspx?cvrnr=26556732
I wonder why
and people beware!
That useall means that the firm are now past!
dispite there site is up and running, if people order somthing the money is most likely gone forever
I measured the Zapfilter2 supply voltages:
Output of filter caps on PSU board: +22.7V / -22.7V
Output of PSU board: +9.8V / -9.8V
The smoothing caps (2200uF/40V) and those big fat resistors (56R) on the PSU board form an RC filter (1.3Hz). The resistors drop about 13V and dissipate more power than the Zapfilter board!
Output of filter caps on PSU board: +22.7V / -22.7V
Output of PSU board: +9.8V / -9.8V
The smoothing caps (2200uF/40V) and those big fat resistors (56R) on the PSU board form an RC filter (1.3Hz). The resistors drop about 13V and dissipate more power than the Zapfilter board!
Just to point out that my voltages were under load.
If you measure the output pins of the PSU board with the zapfilter unconnected, you will not get the voltage drop across the resistors, nor will get any sag from the transformer, so your voltages are probably correct if you measured this way.
If you measure the output pins of the PSU board with the zapfilter unconnected, you will not get the voltage drop across the resistors, nor will get any sag from the transformer, so your voltages are probably correct if you measured this way.
Hurtig said:
Is it easiy to build a output stage similar to zapfilter for a relative newbie like me ?
Any schematics are welcome, i have veroboard and could source film caps and transistors and what else is needed ? I have read the Marantz CD67 400pg thread and had much interest in the discrete output stage. I know the dac has balanced voltage output sony calls it "Advanced Pulse d/a converter" .
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