Just a little one while we work on our Linear supply. I’ve gone skinny with the case design. managed to find some really lovely extruded aluminium that can be used as a case and powder coated. The use of a smaller toroid bolted to the case means case height can drop to 60mm (and match my Naim amp).
I’m also experimenting with an angled fascia - any opinions on this?
Layout so far but this will change when the final PCB layout is ready. I haven’t yet decided if this will be one or two boxes. I like the idea of an all in one, I also like the idea of supply in a single box and Pi in another.
I’d be careful to get the balance in the case right, not feels more ‘low-rent’ than a case with uneven balance.
Linear Supply
I affectionately call this the open box of death. Note the large portion of wooden decking, nothing like home brew… Currently stress testing our new power supply with a stable 1.5A at 5V. Ignoring the Raspberry Pi foundation and some neurotic home brew DIYers we researched what we actually need to supply a nice stable current to drive a streaming application. So far the dual output has supplied the Pi, Allo Boss and isolator while simultaneously supplying another Pi and the IQaudio DAC.
Allo and IQ rematch
Results are very good, no boot problems, dropouts or more importantly noise in the signal, very low noise floor. Even though I’d systematically compared and chosen the Allo DAC as my ultimate component, for shits and giggles I plugged in the IQaudio DAC+ and was very pleasantly surprised. It infused the IQ with a better presentation, less soft, more even, good bass. If you wanted to listen to the music, kick back and enjoy, this is now a good out the box pairing.
Can you have too much bass?
Initially the Allo became acidic, particularly with female vocals, bass was prodigious, still musical but now I can’t help thinking this DAC has a “C” shape presentation. Very detailed top end and extended bass that sometimes sucks a bit out of the mid range. Powering the DAC separately softened this and sat the presentation somewhere between the IQ and the original presentation of the Allo. I’ve since tried the isolator and this softens the presentation further, but keeps the bass and the nice wide soundstage, is this the winner? For my taste it’s close though the IQ is great out the box now with our linear supply. I can’t help but think there is a little too much bass though, for me it seems artificially tweaked. It doesn’t help that my Naim amp also has a little mid bass hump. I’ll be coming back to the IQ a few more times I think but this doesn’t quite have the same soundstage nor detail so neither is “just right” yet…
Suggestions on a postcard
Anyone have a DAC they want me to try? Let me know and if it’s cheap enough I’ll buy it and post my results. Anyone want to send me a DAC they have built to try also let me know. Following the burn test it’s PCB next then the final box…
Can you clarify, I’m sorry I don’t quite understand you. Do you mean the angled fascia doesn’t look as attractive as the curved one?
Weight balance. When you pick up the object it really needs the weight to be evenly spread.
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DACberry One+
Available here: https://www.osaelectronics.com/product/dacberry-one-plus/
All of my listening to digital so far has been with Spotify Connect set to High, Chromecast (analogue out) > Naim Nait XS2 > Royd Atom so my comparisons will be based on this system and switching in and out the DACs to review.
Overall Impressions
So here comes a new contender for the crown. To say I was impressed would be an understatement. After the (relative) complexity of multiple boxes, isolators and such this single DAC with single power supply came in and claimed the crown. It was just very natural, well balanced and accomplished. No fuss, just delivered the goods. Cutting to the shiz:
Bass
CCA : 5
IQA : 3
BOSS : 4
DBerry: 5
Definition and clarity
CCA : 4
IQA : 3
BOSS : 4
DBerry: 4
Soundstage
CCA : 3
IQA : 3
BOSS : 3
DBerry: 4
Naim Flatcap 2
Naim Flatcap 2 guts
Another update to this is that I’ve abandoned the original idea of making an enclosure and instead will be cannibalising an older Naim power supply for the case, making modifications to include the power supply and RPi and Dac. As you can see plenty of room to stuff lots of goodies in there. I’m also considering adding in a Hypex NC252MP for good measure so I can use it as a power amplifier.
I do not recommend Hypex nCore “MP” models, take Hypex nCore 400 with sep. Power supplies as recommended by Hypex.
It is a bit more expensive but a clear advantage! 
Do you not evaluate a Bang & Olufsen ICEpower 125ASX2 2x125W Class D Amplifier Board card?
https://www.ebay.com/itm/Bang-Olufsen-ICEpower-125ASX2-2x125W-Class-D-Amplifier-Board-card/173018437885
I would like to hear opinions.
Sorry but that’s bollocks.
I chose Hypex because I’ve built an amp with their UCD modules and it embarrassed amplifiers costing £££ more. The Ncores take this to another level and are extensively peer reviewed.
In my discussions with Hypex there are no performance differences from the N400 to the NC***MP series.
I’m looking at the Hypex NC252MP, interesting option.
Do you know what I can buy online?
You can only buy them if you have a trade account.
Interesting thread.
My own experience with Spotify is that even on very high, 320kbps, occasionally the sound quality can sound a bit off, whether it’s a local network issue, an issue with that particular Spotify server or rip of the track or something else, I don’t know. I have not gone to the trouble of trying to measure the network stream etc as 99% of the time I use Spotify in the car.
Anyway, I wondered why the tests were done with Spotify “High” which is only 160kbps?
Are you testing with the same playlist of track(s) or different ones as all music is not produced the same, some is downright awful?
I’d have thought listening to a well produced handful of lossless tracks you know well would have been the best way to test, if blind A/B testing is not possible?
Yes that’s my bad, it’s set to 320kbs and it is the same playlist to test.
Hifi is also very much psychoacoustic so your mood will effect perceived outcomes. I’d say if it’s a dodgy sound it’s probably a dodgy mix on Spotify.
Internals removed
So had time to gut the Naim Flatcap and fortunately made a bit of cash as someone wanted the rather hefty transformer. Shame it didn’t suit my application but I’ll be using the ULPS1225A from Oriol at OSA: https://www.osaelectronics.com/product/ulps1225a/
nCore fitted
The Hypex is nice bit of kit well thought out and ludicrously compact. If I had thought about it I may have ordered two mono versions instead but seeing as though this will do 250w into 4ohms that seems a bit greedy…
Decals ready for the new rear panel in Naim style…
I’m pretty pleased about the case, it’s built like a tank and cost £175 if I factor in the sale of the Traffo. To put that in perspective if I had wanted to make a one off version in a similar style with similar materials ProtoCase were going to charge me about £750 
It will match my other Naim gear perfectly and with any luck my genius friend will also get the Naim LED badge to illuminate from the PSU perhaps even with the remote sensor to control the RPi…
Progress has been pretty good but still waiting on the Raspberry Pi PSU from Spain. Received the rear panel back from https://www.schaeffer-ag.de/en/ and they’ve done a good job. Opted for anodised printed as it was cheaper and the results were fine, obviously screen printing would have made a perfect copy for the Naim back panel but would have been significantly more expensive.
However I was over generous with the cutouts for the USB sockets on the Raspberry Pi despite measuring about a dozen times 
Once the PSU has arrived I will reinstall the Hypex module and start soldering things up…
So everything except the USB C power lead and the LED badge is in. I’m going to fire up the Raspberry Pi using the official PSU first to see if it still works via the new RCA leads, then once the LED has arrived wire the rest in and juice it up.
Pi connected to external RCA sockets with Amphenol connectors and Gotham cable
The OSA ULPS1225 Dual Ultra Low Noise Linear Power Supply in all it’s glory
Hypex Ncore waiting to be unleashed
Full top down view
Breakdown of costs:
Naim chassis - £175
RPi Model 4 1Gb - £34
DACBerry ONE+ - £65
OSA ULPS1225A PSU £ 140
Rear panel - £ 68
Silicone rubber flexible power cable - £5
RCA + Speaker binding posts - £25
Fixings (M2.5 + M3 hex) - £5
Standoffs (M2.5 + M3) - £5
TOTAL £ 522
To some this is a lot, but effectively I now have a bang up to date Naim streamer (which costs £2.5k) with the latest open source streaming software. One I can effortlessly upgrade at my leisure. I’ve also got a home for a very nice power amplifier (not included in these costs). These don’t reflect the real costs though, any project has some amount of waste such as the high price of ordering small numbers of items, replacing items that weren’t quite correct, over ordering or design changes mid flight etc. I also cannibalised an RCA cable for the internal connection to the Pi so that’s another £20.
Hope you’ve enjoyed the build thread. If I haven’t blown myself up when it powers up I’ll let you know how it all sounds…
I must say that I admire people who are skilled enough to do these kind of things.
And yes, it is a lot of money. But from what I see it should have more than just a decent sound.
Looking forward to reading your first impression.
Cheers
Thomas