The Best DAC is no DAC

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#1,401
I prefer converting the waw files to DSD and storing in the HDD in DSD format instead of using a computer with powerful processor to convert on the fly, I guess using more powerful processor the PC PSU pollutes more the SQ and now the high space HDD are cheap I use 3.5" because I prefer external linear PSU due to switched PSU pollutes a lot the SQ.

http://www.diyaudio.com/forums/pc-based/290025-resample-pcm-up-dsd2048-service.html
 
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#1,402
Adding "weight" to the filtered DSD output sq.

the no-dac produced a lighter overall balance with a little less weight - Ray
Click to expand...

This reminds me of how my single board DDDAC first sounded. There were two solutions to my DDDAC sounding a little light in weight.
1. Add an analog buffer to the output of the DDDAC - which is what I did and it sounded great.
2. Parallel multiple DDDAC boards - which gets tall and expensive

The equivalent to the "multiple board" DDDAC solution is to run the DSD pulse streams to multi-bit buffers (ex. SN74LVC125AM) to provide 4, 8, or even more outputs through parallel output resistors. The resistor value of the single RC filter is multiplied by the number of output bit streams all going to a single capacitor.

For example, if 8 outputs are used for each DSD bit stream, then eight 3120ohm (390x8) resistors would terminate into one 10nf capacitor. The combined output impedance from the 8 logic buffer outputs would be lower into the RC filter which, theoretically, would provide more "weight" to the music.
 
#1,404
carlsor said:
This reminds me of how my single board DDDAC first sounded. There were two solutions to my DDDAC sounding a little light in weight.
1. Add an analog buffer to the output of the DDDAC - which is what I did and it sounded great.
2. Parallel multiple DDDAC boards - which gets tall and expensive

The equivalent to the "multiple board" DDDAC solution is to run the DSD pulse streams to multi-bit buffers (ex. SN74LVC125AM) to provide 4, 8, or even more outputs through parallel output resistors. The resistor value of the single RC filter is multiplied by the number of output bit streams all going to a single capacitor.

For example, if 8 outputs are used for each DSD bit stream, then eight 3120ohm (390x8) resistors would terminate into one 10nf capacitor. The combined output impedance from the 8 logic buffer outputs would be lower into the RC filter which, theoretically, would provide more "weight" to the music.
Click to expand...

Thanks for the info Carlsor, some food for thought.

My no-dac project has an analogue output stage - A Broskie BCF.

That said, perhaps I wasn't specific enough with my comparative comments; the no-dac sounded less weighty than the Beresford in the Beresford's 'home' system and I don't have the same perception in my own system.

Ray
 
#1,405
merlin el mago said:
I prefer converting the waw files to DSD and storing in the HDD in DSD format instead of using a computer with powerful processor to convert on the fly, I guess using more powerful processor the PC PSU pollutes more the SQ and now the high space HDD are cheap I use 3.5" because I prefer external linear PSU due to switched PSU pollutes a lot the SQ.

http://www.diyaudio.com/forums/pc-based/290025-resample-pcm-up-dsd2048-service.html
Click to expand...

Makes a lot of sense when your DAC is directly connected to your server PC and if the DAC is not perfectly isolated (most of them), so this is what I do as well for now.

There's an alternative: do real-time up-conversion to DSD and segregate the computer server from the DAC using HQ Player in client-server mode, i.e. in conjunction with Miska's networkaudiodaemon running on an NAA device (eg BeagleBone Black) and both connected with Ethernet (and Fibre optic if you can), and the BBB then connects to your DAC either by USB or I2S if possible.
 
#1,406
My DAC isn't directly connected to my PC, I use 3.5 HDD powered with external regulated linear PSU connected to my laptop, between my laptop and No Dac I have Amanero USB-I2S and between the Amanero and No Dac I have DIYINHK I2S isolator, Amanero powered Salas BiB shunt regulator, DIYINHK powered Salas Reflektor-D. As player I use Daphile free with very good SQ.
 
#1,407
no-dac sound "weight" idea - correction

I changed the wrong RC values in my previous post which resulted in a combined RC filter with the same resistor and capacitor values as the filter driven by one digital output.

Using a 10 bit digital buffer (74LVC827) - a correct example of what I was suggesting is each buffer channel output feeding a 390 ohm resistor all of which terminating in a single 0.1uf capacitor. This is the equivalent to combining 10 single DSD digital filters which may make a difference in sound impact. This would depend on the down steam load. But if the sound is "weighty" enough then I wouldn't bother with this.

In order to get rid of the 1.65V DC offset I modified my AD815 buffer/gain circuit to get rid of this DC offset without requiring the use of a coupling capacitor. This circuit can be used before or after the DSD digital bit stream filter. I just ordered a set of modified PCBs to test this idea.
 
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#1,408
I2SoverUSB input voltages

While I am waiting for my I2SoverUSB board I'm trying to figure out the best method to supply external power supplies (or not) to the (I2SoverUSB) board.
On the JLSounds I2SoverUSB specs pdf page there is the option to provide both the USB and the generators and the reclocks with separate external power supplies.

Is this the way to go or is the generator and reclocks PS (pins 11 & 12) the critical one and the USB PS (pins 1 & 2) can be fed by the USB cable from the laptop?

Thanks
 
#1,409
marcus1 said:
While I am waiting for my I2SoverUSB board I'm trying to figure out the best method to supply external power supplies (or not) to the (I2SoverUSB) board.
On the JLSounds I2SoverUSB specs pdf page there is the option to provide both the USB and the generators and the reclocks with separate external power supplies.

Is this the way to go or is the generator and reclocks PS (pins 11 & 12) the critical one and the USB PS (pins 1 & 2) can be fed by the USB cable from the laptop?

Thanks
Click to expand...

At the very least I would provide the 'clean' side (i.e. the reclocking) with its own high quality power supply.

Ray
 
#1,410
carlsor said:
I changed the wrong RC values in my previous post which resulted in a combined RC filter with the same resistor and capacitor values as the filter driven by one digital output.

Using a 10 bit digital buffer (74LVC827) - a correct example of what I was suggesting is each buffer channel output feeding a 390 ohm resistor all of which terminating in a single 0.1uf capacitor. This is the equivalent to combining 10 single DSD digital filters which may make a difference in sound impact. This would depend on the down steam load. But if the sound is "weighty" enough then I wouldn't bother with this.

In order to get rid of the 1.65V DC offset I modified my AD815 buffer/gain circuit to get rid of this DC offset without requiring the use of a coupling capacitor. This circuit can be used before or after the DSD digital bit stream filter. I just ordered a set of modified PCBs to test this idea.
Click to expand...

This looks interesting, both the 'parallel drive' and the AD815 mod; perhaps you'll share more in due course?

Ray
 
#1,411
merlin el mago said:
My DAC isn't directly connected to my PC, I use 3.5 HDD powered with external regulated linear PSU connected to my laptop, between my laptop and No Dac I have Amanero USB-I2S and between the Amanero and No Dac I have DIYINHK I2S isolator, Amanero powered Salas BiB shunt regulator, DIYINHK powered Salas Reflektor-D. As player I use Daphile free with very good SQ.
Click to expand...

OK, so you seem to be saying your DAC is well-isolated from your computer.

In that case, do you hear a difference between playing an offline converted PCM->DSD and sending a real-time up-converted PCM->DSD file?
 
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