So I have this connected now. I had a preconfigured Pi 3B+ running Ropieee so I simply fitted the DAC, booted up, picked the DAC on the Ropieee web page, disabled USB and rebooted. I am just listening through a quality head amp and headphones and it is really quite good. More pleasing than the same Pi feeding an Explorer 2 into the same rig. It is a big thumbs up from me.
One observation is supplying spacers as per the assembly video would be useful. Other than that I am a very happy customer!
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Thanks for doing a write up on facebook:
Here is a review that was just posted on diyaudio:
http://www.diyaudio.com/forums/vendor-s-bazaar/321303-applepi-dac-performance-raspberry-pi-dac-post5520363.html
I was part of the ApplePi tour and want to share my impressions of this DAC.
HARDWARE
I tested the hat with Rpi 3B, IanCanada IsolatorPi, and Allo Kali. Each board had separate power: I fed the Pi with an iFi iPower and the other three boards each got a GStew modified Jameco linear wall wart. Listening environment was a rather analytical nearfield desktop setupāa Tripath amp into some Axiom 2 way bookshelf speakers, and a humble full-range setup using another Tripath amp with Aura NS3 drivers.
First surprise: This DAC seems to be immune to PSU noise! Other DACs I have tested are all very sensitive and exhibit hum and hiss to some extent, even with an isolator board, Kali, and four separate power supplies with earthed ground rails via John Swenson Ground Tweak. Using these careful measures, I have been able to reduce noise by, say, 95% with the other DACs. But I can still hear a tiny bit near the speaker when music is stopped and I crank the volume knob to max.
In contrast, ApplePi is silent. Even if I float the PSU grounds by unplugging my earth wires from the negative terminalsā¦it stays silent! The other DACs would be intolerably noisy this way. Iām impressed. This could make getting good sound from a Pi a heck of a lot less hassle and expense.
(edit: Since this test I have booted the iPower out of my setup completely, and going completely linear in combo with the IsolatorPi killed noise at the speakers almost 100% for any DAC Hat on my Pi stack )
SOFTWARE
I played music through the ApplePi with both Moode and Volumio. I was not able to get 16/44.1 files to play natively on ApplePi with Volumio, though Leo told me this works for him. It did play 24-bit files quite nicely, but everything in 16-bit I had to upsampleā¦and IME Volumio upsampling sounds sort of lifeless. Thus, I spent most of the time playing my music collection (which is 95% Redbook FLAC) via Moode, which worked flawlessly, natively decoding all bit depths and sample rates I tried.
SOUND
One huge advantage this DAC holds over all others I have tried is the beastly 2.5V outputāit just makes both of my amp/speaker combos sing, almost like having a preamp. This results in some of the best, most effortless bass control I have heard in my systems to date. I wish every source component had such gusto. In both my systems, ApplePi made my little flea-powered Tripath amps able to push significantly more air from the woofers without distortion. (Note to self: buy a real amp). IME good gain staging just makes everything downstream happier. Take note: the board gets quite hot. Leo said he has made some revisions to help dissipate heat better with the production boards.
Entering into highly subjective territory, now. My listening impressions parallel my experience with Alexās DIAL_DAC to a great extentā¦the sound signature shared between the sibling Burr Brown chips is evident. Analytical and smooth at the same timeādetailed without harshness. Especially with 24/192 files, transparency is excellent.
I feel that the powerful, controlled bass and detailed treble are the most apparent and expressive parts of the music with the ApplePi. At this point I have to reveal myself as a total sucker for midrange body and warmth. Thus, the ApplePi doesnāt push all my buttonsā¦in fact, Iād say it stands in slight contrast to the meatier tonality of the TDA1387 DACs which usually sit atop my Pi stack. Which flavor youāll prefer will surely depend on the other gear in your system as well as your personal taste.
Nice job, Leo.
Orchard Audio will be releasing a standalone DAC based on the ApplePi DAC architecture. For details see here:
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We are celebrating the opening of our online shop. Get 10% off ApplePi DAC:
https://orchardaudio.com/shop?olsPage=products%2Fapplepi-dac
Case for ApplePi DACā¦
Thanks to one of my customers (Rick D.) I can say that the HifiBerry Universal Case, fits the ApplePi DAC perfectly:
https://www.hifiberry.com/shop/cases/universal-case-black/
I would highly recommend getting these heat sinks for the DAC chips:
https://www.newark.com/fischer-elektronik/ick-smd-a-8-sa/heat-sink-dip-ssop-tssop/dp/34M6428
In addition to the heat sinks I additionally recommend drilling a few holes in the top cover to improve airflow.
The case will not work with ApplePi Volume-Clocker.
Here are some pictures:
I was looking at those and wondering if they would do the job. Great spot by Rick!
For those who may be interested check out GALA, it is essentially a fully stand alone version of ApplePi DAC with SPdif input.
20% off all ApplePi products until Nov 30th. Get yours now:
https://orchardaudio.com/shop?olsPage=products
For a limited timeā¦
ApplePi DAC - 30% off
ApplePi Volume-Clocker - 15% off
Check it out:
https://orchardaudio.com/shop?olsPage=products
Edit: questions withdrawn as I realized everything was pictures on your website. I just had to swipe.
One thing Iām wonderingā¦ are you running the two PCM1794s each in differential mode and thereby able to run in differential [balanced?] mode thru the opamps to the output?
Both DACs are run in monaural mode with dual differential output stages, providing for a true balanced output.
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Thank you. I purchased the dac with header and power supply.
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It will ship tomorrow, you should have already received a tracking number.
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For those who may be interested here is a great write up by a very happy customer.
It goes though the process of building a system from scratch with the official 7" touch screen.
http://www.cfuttrup.com/touch_upgrade.html
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Thanx! Great. Iām building my 3rd RoPieee device with 7" screen this time with the ApplePi.
P.s. I like the scientific papers published there too.
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Btw, thought Iād throw this out there. Of all the tests I saw of this dac on audio science review, what clinched it for me was the nature of the harmonic distortion.
Yes, it is super low and really should not even be detectible. But what there is of it, the low even order harmonics dominate; balanced out is even better. The nature of the harmonics is very āsingle ended tube -likeā. If there is going to be any distortion (however minuscule) thatās the kind you want it to be! 
Do you have a UK distributor for the dac Leo?
Everything ships from USA.
Man, what a detail moster this DAC is! I highly recommend it.
I received this Monday. But wanting to get a feel for this DAC first using balanced, I held off hooking it up right away. I recieved the mini to full size xlr cables today. So I went ahead and swapped out the Boss dac I was using on a RoPieee plus screen for this. Swapped in some taller standoffs, did some more trimming of the 7" case to accommodate this dacās connectors, and I was ready to go.
A few minutes into listening, the snow squall that accompanied the onset of the polar vortex knocked out power to me and 902 of my closest neighborsā¦ lol Was worried the linemen couldnāt go up in their buckets in the cold and wind. Just when I was sure Iād need to go out to buy gasoline to run my generator to power my furnace and circulators to prevent freeze of the pipes at the periphery of my house, I got the power back (note to self: buy gasoline). Feed the dogs. Feed myself. Then let the auditioning [re-]commence.
The signal path is Roon playing my playlist of favorite songs I know extremely well (a mix of ripped Redbook and purchases from HDTracks all in FLAC) > RoPieee + screen with this ApplePi HAT > Balanced out > Mjolnir balanced in > 4-pin XLR out > HiFiMan HE-1000 (gen 1). A fully balanced signal path from source to output. Love it!
As far as balanced headphone amp is concerned, I only have a Mjolnir gen 1 here. My Woo WA-22 and McIntosh MHA-100 (the latter has balanced in, but is a single ended amp) is at another address. And ideally what Iād mate to this very competent DAC.
The Mjolnir is no slouch tho. With this dacās balanced level out, the volume dial only needs to go to 12 oāclock instead of 4 or 5 oāclock (when I use unbalanced in, so that I can use an analog tone control) for very very loud musical reproduction. But Iāll be totally honest. Its dry analytic, almost ābass-liteā nature isnt the best match for this detail monster of a dac. So after a few hours tweaking the DSP in Roon, I settled on this extremely subtle tonal rebalance you see below. I highly recommend this simple form of single band tonal shaping either cutting highs or lows as necessary for your dac-amp-transducer pairing; play with the center frequency and Q, but keeping Q (well?) under 0.25 is recommended. If gain level goes much over 1 you may find the transients and attack getting cut by an excessive degree.
Edit: I stand by the above. But wanting more presence ābiteā, and to account for a range where the frequency response of the he1k dips more than I prefer, Iāve since adopted using this, still simple and subtle, parametric curveā¦
In any case, dont take this as a criticism of the Mjolnir or the ApplePi. This 1db reduction of the highs is a subjective preference. And I doubt Iād want this with the other two premium amps I own that I named. Tbd at a later time when I move all my Roon & Bridge devices to where those amps live.
I will say thisā¦ with the Mjolnirās accuracy, precision, and well damped nature that is free of all embellishments and colorations, fed by the ApplePi doing an exceptional job recreating the analog signal of the original recording free from any auditory masking with itās super low noise floor and low low distortion dominated by even harmonics many orders out (what little there is of it, balanced out) , jitter immunity, and excellent transient response, this is perhaps the most revealing yet still musical combo I have. The things so often lost/masked, subtle modulations of instruments, the subtle backing tone of a synth in a mix, is as discernible as the primary melodies & percussion of the music. It gives my NAD M51 driving either my MHA-100 or WA-22 a run for its money at a mere fraction of the cost. Nirvana on a budget.
Itās been three hours since I settled on this dsp curve (Edit: I actually powered down at 4am unable to pull myself away, spending about 7 hours evaluating this combo) ā¦ Iāve listened to downtempo, pop, pop-dance, various jazz styles, electronica, you name it. And I havenāt had a single complaint of what was coming out of the HE-1000s. Havenāt had the slightest desire to alter the level of the treble, mid, or bass. For me, a habitual tone control tweeker (Perreaux TC2 is my favorite), thatās huge! This happens only when so many things line up perfectly so that something close to (subjective) perfection is coming thru the transducer.
I highly recommend the ApplePi! On sale, itās a no-brainer!
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