Soekris' DAC implementations

stuff that shouldnt matter but does

put the scope on the clock output couple of days ago and was less than excited about the waveform
got me thinking that sharing one cell with the clock, fpga, microcontroller, usb to i2s device and the + vref rail might not be so hot of an idea

so i added another cell just for the vref so that +/- vref has a cell each and the 'front end" has its own cell

wouldn't mind this one was supposed to be the minimalist version

anyway soundstage opened up a little more, clarity, focus etc
thats not really that surprising after all i was dumping all the front end digital noise on + vref

As im a big fan of providing exceptionally clean power to clocks
for fun i bridged a wire direct from where i inputed the 3.3v rail into the board to the clock ps pad
i wasn't expecting any improvement but the sq resolution had increased
i was so surprised i ab tested a few times to make sure

22858826781_e798eea6dc_c.jpg

i also ran a bridge from clk gnd
i ab tested it too
it might have helped a bit but its not a big enough change to be absolutely positive, im gonna leave it there for now as it sure aint doin any harm
22821661236_8464bc69a0_c.jpg
22455418229_7becba42da_c.jpg

put the scope on the clock again the waveform is much better but not as good as id like
 
TNT,

Your prediction did not take long to come true.

Have removed Vref and ready to install batteries.

Just because they are here and I think in some ways it will be easier I am using a pair of batteries for each channel and wiring up to the batteries with separate wires for each shift register akin to the HIFIARDUIINO's cap mod. The wires have to be so small and a multiple has to be a little better.

I feel certain Nigel will do the same thing eventually.

As he has made clear his work was the result of a (brilliant) mistake that summons that legendary mother of invention, necessity, after destroying a Vref which lead to putting something together quickly. Opportunity to do what he has been talking about from the beginning of this project.

I am trying to explain away my insatiable need for one-upsmanship.
 
I modded the clock PS too but more conventional, just adding some caps.
I've built two cap towers around the clock.

Sound quality went up another level 🙂

so timings important for music 😉

doubt theres much out there to match a lifepo4 cell for clk dutys
generally speaking i find the clk ps far far more important than choosing one clk over another, usually translates into resolution and fluidity of the sound
 
Hey nige, inspired by your work! I'm not at all surprised by the improvements you are reporting - I used lifepo4s for the analog supply and clock of my Buffalo 1 a while back, with similar results. Are you using a dedicated charging chip, or hanging them onto conventional supplies? Ta.
 
Hey nige, inspired by your work! I'm not at all surprised by the improvements you are reporting - I used lifepo4s for the analog supply and clock of my Buffalo 1 a while back, with similar results. Are you using a dedicated charging chip, or hanging them onto conventional supplies? Ta.

a linear bipolar supply for +/-3.3v (doesnt matter too much what it is) in parallel with the battery cells( switch in between cells and ps and another between cells and dac )

similar to alarm systems power backup and car alternator charging etc
 
Hey nige, inspired by your work! I'm not at all surprised by the improvements you are reporting - I used lifepo4s for the analog supply and clock of my Buffalo 1 a while back, with similar results. Are you using a dedicated charging chip, or hanging them onto conventional supplies? Ta.

Glad to hear you are coming around to the "Nigel Method" of float charging the batteries.

You were dismissive a few months back.