Soekris Dam Dac

[nige2000]

found an explaination why i might be so found on synchronous reclocking
https://www.lessloss.com/faq.html?q=asy ... reclocking

[wushuliu]

Added the flipflop with master clock from the soekris. The flip flop and 3.3v isolation are powered with a wallwart---lm317 kit--> lifepo4. Need to spend more time but the presentation is smoother with a sense of ease to it. I would say the lessloss description seems about right. I am very, very happy with the sound quality. I may try to power the wm8804 with the lifepo next, but think I'll settle with things as they are for now.

[nige2000]

Added the flipflop with master clock from the soekris. The flip flop and 3.3v isolation are powered with a wallwart---lm317 kit--> lifepo4. Need to spend more time but the presentation is smoother with a sense of ease to it. I would say the lessloss description seems about right. I am very, very happy with the sound quality. I may try to power the wm8804 with the lifepo next, but think I'll settle with things as they are for now.

cool
i think of it like a sort of pre-alignment
only killer is knowing the fpga master clock out isnt as optimal as we would like it to be
is reverb decay etc better?

[wushuliu]

Added the flipflop with master clock from the soekris. The flip flop and 3.3v isolation are powered with a wallwart---lm317 kit--> lifepo4. Need to spend more time but the presentation is smoother with a sense of ease to it. I would say the lessloss description seems about right. I am very, very happy with the sound quality. I may try to power the wm8804 with the lifepo next, but think I'll settle with things as they are for now.

cool
i think of it like a sort of pre-alignment
only killer is knowing the fpga master clock out isnt as optimal as we would like it to be
is reverb decay etc better?

I got the WM8804 powered by lifepo yesterday, as well as the main Oppo 27mhz clock. Reverb and decay are a little better, but nothing like when I had the RedNet 3, which was *really* good at that. Now that the batteries are in the mix, what I hear is blacker background, micro detail, and purity of tone. Sound quality is almost indistinguishable I think from vinyl. Truly analog sounding in some respects. Now I'm intrigued by powering the soekris registers with lifepo, but no more room in my enclosure and I am done with this phase of tinkering for the year.

So glad I left the USB stuff behind - even stock I preferred the Oppo's ethernet streaming. I think I am too sensitive the USB 'sound', the underlying hash that no matter what you add to the chain, lingers all the same.

And thanks for all your help, I've learned a lot!

[nige2000]

Yes would recommend doin the vref
Easiest step is three cells two for 3.3 and one for -3.3
Remove vref regs and 1.2v switch mode reg and replace with an ldo powered direct from cell
The other mods are much work

computer audio is deeply flawed
theres just far too much to fix
but it can be done with much expense on time and money
with various power supplies, clocks, usb cards isolators reclockers

[jrling]

Would it be worth it to convert my spdif/coaxial input to the soekris to I2S via a WM8804 or better to stick with spdif? (no longer using usb2spdif inputs)

dont know
i do remember a few guys having preference for i2s sources over spdif
if its cheap to implement might be an interesting experiment

whats your spdif source?

I know this thought process has moved on a bit, but nige's useful link to the informative LessLoss FAQ - https://www.lessloss.com/faq.html?q=i2s has an interesting pros & cons of going the I2S route which clearly is not a universal panacea.

It is not true that using any three cables for I2S unbalanced signal transfer will automatically result in less Jitter at the DAC chip itself. Indeed, it can actually easily be argued that the Jitter induced in Clock extraction from SPDIF can actually be less than the Jitter induced by using three clock cables (which are all antennae). You raise the RF induction by three times the amount when using three cables in comparison to using only one well shielded one.

Must say that I was interested in what SQ results from using the Oppo 103 as a PC Ethernet bridge convertor to SPDIF to DAC architecture. As a way of avoiding USB altogether.
But, of course, there are technical downsides in using Ethernet as a digital streaming transport mechanism, that may outweigh the galvanic isolation brought to the party by Ethernet transfer. Probably getting a bit too much off piste for this thread.

[nige2000]

Would it be worth it to convert my spdif/coaxial input to the soekris to I2S via a WM8804 or better to stick with spdif? (no longer using usb2spdif inputs)

dont know
i do remember a few guys having preference for i2s sources over spdif
if its cheap to implement might be an interesting experiment

whats your spdif source?

I know this thought process has moved on a bit, but nige's useful link to the informative LessLoss FAQ - https://www.lessloss.com/faq.html?q=i2s has an interesting pros & cons of going the I2S route which clearly is not a universal panacea.

It is not true that using any three cables for I2S unbalanced signal transfer will automatically result in less Jitter at the DAC chip itself. Indeed, it can actually easily be argued that the Jitter induced in Clock extraction from SPDIF can actually be less than the Jitter induced by using three clock cables (which are all antennae). You raise the RF induction by three times the amount when using three cables in comparison to using only one well shielded one.

Must say that I was interested in what SQ results from using the Oppo 103 as a PC Ethernet bridge convertor to SPDIF to DAC architecture. As a way of avoiding USB altogether.
But, of course, there are technical downsides in using Ethernet as a digital streaming transport mechanism, that may outweigh the galvanic isolation brought to the party by Ethernet transfer. Probably getting a bit too much off piste for this thread.

i think they meant in the context of taking in an i2s signal from outside the dac case
where using a spdif cable could be preferable to an unshielded i2s

i2s is pretty common in dac chips
implementation will have much to do with the results

we've done experiments with intona and regen were usb isolation has proven to be far more effective than i2s isolation
which seems to suggest that most of the damage has occurred in the usb to i2s conversion by a sloppy usb signal
which doesn't seem to be fully cured by "audiophile" usb cards
Johns prototype isohub was pretty much a hit at the meet up here a few weeks ago
i think these type devices will be a must for usb dacs

[jkeny]

i think they meant in the context of taking in an i2s signal from outside the dac case
where using a spdif cable could be preferable to an unshielded i2s

i2s is pretty common in dac chips
implementation will have much to do with the results

Yes, agreed

we've done experiments with intona and regen were usb isolation has proven to be far more effective than i2s isolation
which seems to suggest that most of the damage has occurred in the usb to i2s conversion by a sloppy usb signal
which doesn't seem to be fully cured by "audiophile" usb cards
Johns prototype isohub was pretty much a hit at the meet up here a few weeks ago
i think these type devices will be a must for usb dacs

There seem to be two issues that need addressing in USB signalling - common mode noise & signal quality
Common mode noise seems to be a much more common issue than previously credited when connecting USB devices to computers.
Removing this CM noise requires some sort of isolation that works prior to the USB receiver chip. In my experience isolation after the USB receiver is only partially effective. Isolation prior to USB receiver usually entails an isolator that works at USB high speed (480Mbps)

Any USB isolation I have experienced is also improved by having something that regenerates the USB signal with a certain quality & located close to the final USB receiver

[wushuliu]

Yes would recommend doin the vref
Easiest step is three cells two for 3.3 and one for -3.3
Remove vref regs and 1.2v switch mode reg and replace with an ldo powered direct from cell
The other mods are much work

computer audio is deeply flawed
theres just far too much to fix
but it can be done with much expense on time and money
with various power supplies, clocks, usb cards isolators reclockers

Which is why I think using the ethernet streaming with the Oppo is interesting. I don't need to think about PC playback software and how they may impact the sound or
usb or any of that. I just select the music drive to be shared in Properties and let the Oppo UI take care of the rest. I would think this minimizes how much you need to mess
with PC optimizations. With the exception of the hard drive power. I plan on making a power supply for that. Should be simple.

To be vaguely back on topic - one of the lessons I've learned is that retail DACs are a package of hidden compromises, I can't imagine not sticking with diy from here on out...

[jkeny]

To be vaguely back on topic - one of the lessons I've learned is that retail DACs are a package of hidden compromises, I can't imagine not sticking with diy from here on out...

Not all retail DACs :)