Leo
Do you think a different power supply would make sound different on Pi? like a iFi one?
I did all of my testing with the 5.25 V power supply. That is the only power supply that I personally tested.
I have had multiple customers tell me that using a separate power supply for the dac and the raspberry pi helped. These customers were also using isolators, so I have a feeling the isolators is what helped more because they probably had a ground loop issue in the system.
If you end up trying different power supplies, I would like to hear about it.
For most DAC boards, a better/cleaner power supply always seem to improve sound quality. With Isolators, even more improvement seems possible.
Check other threads to read up on what you can expect. There are also some good youtube reviews you could check.
As always, ymmv…
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For most DAC boards, a better/cleaner power supply always seem to improve sound quality. With Isolators, even more improvement seems possible.
Check other threads to read up on what you can expect. There are also some good youtube reviews you could check.
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Thank you for reply. PSU is a frequent topic for each Raspi DAC. I just wonder why there isn’t a discussion about Pi. I found iFi is the one referred to mostly on internet. However, its current leakage problem was discovered by Allo’s team. I am not an electronic engineer and no idea about how it affects the SQ. It seems a better solution is coming soon and I am watching at the progress.
I want to know more information about ifi issue. Can you post info or link?
A latest review on diyaudio talking about the PSU noise on Pi. That is pretty interesting. It would save my money if a good independent PSU isn’t necessary.
Here is the 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 setup–a 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 terminals…it stays silent! The other DACs would be intolerably noisy this way. I’m 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 upsample…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 output–it 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 Alex’s DIAL_DAC to a great extent…the sound signature shared between the sibling Burr Brown chips is evident. Analytical and smooth at the same time–detailed 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 doesn’t push all my buttons…in fact, I’d say it stands in slight contrast to the meatier tonality of the TDA1387 DACs which usually sit atop my Pi stack. Which flavor you’ll prefer will surely depend on the other gear in your system as well as your personal taste.
Nice job, Leo.
There is a comparison review on ApplePi and Katana
Thanks for bringing this to my attention, I don’t know how they were measuring SNR but they clearly made mistake, my specifications are correct. I will contact them though the forum.
Orchard Audio will be releasing a standalone DAC based on the ApplePi DAC architecture. For details see here:
indiegogo.com/projects/gala … x/19247162
Would appropriately-placed stick-on heatsinks improve things?
Chris M
I have been running a board for close to a year straight now with no issues.
This heatsink will sit nicely on the 1794s if you like to keep them a little cooler:
https://uk.farnell.com/fischer-elektronik/ick-smd-a-8-sa/heat-sink-for-smd-87-c-w/dp/4302175
Case for ApplePi DAC…
Thanks to one of my customers (Rick D.) I can say that the HifiBerry Universal Case, fits the ApplePi DAC perfectly:
hifiberry.com/shop/cases/un … ase-black/
I would highly recommend getting these heat sinks for the DAC chips:
uk.farnell.com/fischer-elektron … dp/4302175
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 Volume-Clocker
Here are some pictures:
I’ve had my ApplePi DAC running for a few weeks now, and after the running-in period of a day, I have to say it’s a goodie. I’d love to have the critical faculties that would allow me to make detailed comments about sound-stages and suchlike but being 61 and a motorcyclist means that my hearing is degraded from my youth. It’s not the kit it’s playing through; the speakers now sound like NS1000s, so they’re doing fine.
What I can say is that there’s more music over the HFB DAC+ Pro; it’s a richer sound and I can differentiate between areas of the sound-stage more cl;early. I like it and I admire the simplicity of the design. Having spent time in the electronics industry, one becomes very aware of how complexity breeds breakdowns, so someone following Colin Chapman’s advice (‘Simplify, then add lightness’) is one to watch with interest.
Chris M
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:
Here is a great write up by very happy customer.
cfuttrup.com/touch_upgrade.html
If you are looking to build a system with the 7" touch screen that is very useful.
For a limited time…
ApplePi DAC - 30% off
ApplePi Volume-Clocker - 15% off
Check it out:
orchardaudio.com/shop?olsPage=products