Re: Filter Response ?
Pass D1 uses 1,5k parallel to 2,7nF = 40,5kHz f_o for the 2mA PCM63. So 3V peak per branch.
I use 6,5k and 680pF = 44kHz f_o for my TDA1547 just giving 0,1mA. Just 0,65V - so 1,3V on XLR. Enough for no use of the volume adjuster of the D1.
Simply calculate your values for your DAC used.
promitheus said:What is the frequency response of the I/V stage from the D1?
I will be using upsampled data and want the filter to be above 48Khz.
Pass D1 uses 1,5k parallel to 2,7nF = 40,5kHz f_o for the 2mA PCM63. So 3V peak per branch.
I use 6,5k and 680pF = 44kHz f_o for my TDA1547 just giving 0,1mA. Just 0,65V - so 1,3V on XLR. Enough for no use of the volume adjuster of the D1.
Simply calculate your values for your DAC used.
That´s how much I calculated last time so I wasn´t wrong.
I am planing on designing a PCB for the I/V stage. I want to replace the 4 opamps in my DAC to this.
Is anybody interested?
I want to use silver mica for the small caps.
Panasonic FC for the electrolytics.
I probably will use 4,7 uF MKP caps for the output.
I am planing on designing a PCB for the I/V stage. I want to replace the 4 opamps in my DAC to this.
Is anybody interested?
I want to use silver mica for the small caps.
Panasonic FC for the electrolytics.
I probably will use 4,7 uF MKP caps for the output.
the schematic
Hi,
I put "my" schematic - it is more a schematic of the one and only, because I just combined P1.7 and D1 circuits – online http://www.audiomap.de/forum/index.php?az=show_mesg&forum=116&topic_id=15097&mesg_id=15147&page= . Sorry, but again in German language and in another forum. I have problems to put my stuff into here (don´t know why), so I refer to the other forum which offers somewhat easier data download.
The key massage: find your own bias current! The sound is changing really radical from 3mA up to 10mA through the 2SK389. Also the DAC current will for sure change the best current value. Put one trimming resistor 150Ohm plus 63Ohm in line in for R2 and adjust the bias current. Then set R1 to U_b/2 and listen…
Test it, the sound is perfect!!!!!!!!!!!!!!!!!!!!!! Pics of my hardcore P2P work under the link in the quoted words above.
Regards
Klaus
Klaus said:
More to follow but for the curious guys already some pics... (sorry in another forum in German language) http://www.audiomap.de/forum/index.php?az=show_mesg&forum=116&topic_id=15097&mesg_id=15097&page=
regards
Klaus
Hi,
I put "my" schematic - it is more a schematic of the one and only, because I just combined P1.7 and D1 circuits – online http://www.audiomap.de/forum/index.php?az=show_mesg&forum=116&topic_id=15097&mesg_id=15147&page= . Sorry, but again in German language and in another forum. I have problems to put my stuff into here (don´t know why), so I refer to the other forum which offers somewhat easier data download.
The key massage: find your own bias current! The sound is changing really radical from 3mA up to 10mA through the 2SK389. Also the DAC current will for sure change the best current value. Put one trimming resistor 150Ohm plus 63Ohm in line in for R2 and adjust the bias current. Then set R1 to U_b/2 and listen…
Test it, the sound is perfect!!!!!!!!!!!!!!!!!!!!!! Pics of my hardcore P2P work under the link in the quoted words above.
Regards
Klaus
it works again!
Our system admin maybe has changed again the security settings, now it works again. Nice!
The pic shows the mini sized D1 clone I/U + buffer stage. Fully symmetrical (4 "channels") and two voltage regs a la P1.7 in the middle. The 610/9610 lock somewhat pressed in, because I originally layouted for smaller FETs. The sound is unbelievable nice. I trust in Nelsons circuits and just copy them.
Hopefully the other day a nice, small PCB would be available for this stage. Small to bring it into given packaging situations. By adjusteing two R´s and the filter cap it can easily by adapted to each DAC with symmetrical current output.
Regards
Klaus
Our system admin maybe has changed again the security settings, now it works again. Nice!
The pic shows the mini sized D1 clone I/U + buffer stage. Fully symmetrical (4 "channels") and two voltage regs a la P1.7 in the middle. The 610/9610 lock somewhat pressed in, because I originally layouted for smaller FETs. The sound is unbelievable nice. I trust in Nelsons circuits and just copy them.
Hopefully the other day a nice, small PCB would be available for this stage. Small to bring it into given packaging situations. By adjusteing two R´s and the filter cap it can easily by adapted to each DAC with symmetrical current output.
Regards
Klaus
Originally posted by Klaus I use the Panasonic FC electrolytics + MKP bypass because they sound extremely open, dynamic and w/o any sonically problems for ca. 2€.
It is my humble opinion that the Panasonic electrolytic types
are quite good for audio if you need for than about 10 uF, and
of course you bypass them with the film cap of your choice if
you want. And they are cheap and available.
Hey Klaus,
That forum looks dead and finds nothing before 9/2004 ... does this still exist?
I put "my" schematic - it is more a schematic of the one and only, because I just combined P1.7 and D1 circuits – online HiFi Heimkino Forum . Sorry, but again in German language and in another forum.
That forum looks dead and finds nothing before 9/2004 ... does this still exist?
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