what next i2s or USB hub?

Audio Gear DACs
1

Ok, so my initial experiment is a good success. Have my old fashioned pi running volumio 1.5.
Setup is as follows;
1amp micro usb wall wart from RS -> raspberry Pi (Ethernet not WiFi) -> USB : musical fidelity V-link : spdif -> midiman flying cow DAC -> Little dot mkiii tube headphone amp -> denon AH-D2000 or AKG-701

Uses Ethernet cable, SD card reader in USB and smb nas for flacs and 320 mp3s. No USB HDD, yet.

The V-link is asyncrnous USB and runs up to 24bit 96khz. It runs smoothly since day 1 with no pops or dropouts.
The flying cow is now obscure and will ultimately be upgraded soon, but gives me no cause for concern yet. (From back in the day when the concept of a separate DAC was a bit fresh) possibly to a Schitt modi, or bifrost if I can sell my kidney.

So my question is, what do I upgrade. If anything. I know the pi’s USB power supply isn’t pretty, I will happily get a quality powered hub, if someone can recommend one that is clean and qualify then I’d appreciate it. As I understand I can feed the pi from that, hub feed s the pi data usb back out to the hub and plug in the v link and any other things.
Well this isolate any power noise the pi males via the hub? Or is there a diy way to cut the Pis outbound power feeding back to the hub? Only passing data tx.

Is it worth investing in a i2s output (I’d go for hifiberry spdif out, as a £30 dac would be a massive downgrade from the £125 flying cow). To avoid usb noise and the PiS power noise? Or am I not going to notice an improvement vs my usb v link?
I.e are there other audiophile indescribable improvements for the i2s hiberry digi? I’ve heard mixed results vs good USB vs i2s even if it makes good sense to skip unnescesary busses and talk direct with i2s it sounds like a sync USB might reduce jitter by having an external clock? (On shaky ground\ knowledge here)

Thanks volumio for a stonkingly good distro

2

If you get good, non-skipping performance out of asynchronous USB then there is atleast in theory no reason why i2s should sound better. The fact that theres less ‘stuff’ in the digital path does not neccesarily affect sound, as long as your DAC gets the bits in time and converts them to analog in a steady clock. An Async DAC should do just that. So if you are happy with your DAC, stick to it. If not, then get a better one :slight_smile: Both USB and i2s have their advantages to consider. Do keep in mind that not all ebay i2s DAC boards are very well/professionally designed and/or built. A fancy DAC chip is only half the story, topology and execution being equally important (if not moreso).

As for power, a USB DAC (or any DAC) will definitely benifit from a good power supply. Powered USB hub could work, but even better would be a 5Vdc regulated power supply. And then split the USB cable signal and power cables. If this is too much DIY for your taste, there are ready-made solutions that do the same like like squeeze-upgrade, and have a feed-through USB connector.

3

Thanks, really helpful.
I was definitely weary about an eBay job component having all the right value in the right places. If I end up with a spare £30 I’ll try the hifiberry digi but for now that goes down the list.

AW hell no, not scared of DIY electronics. I’m in the process of learning about power regulation for an arduino\ esp8266 project. But am still quite green when it comes to good power supplys.

Can you recomment a good quality 5v regulated DC supply or any tips on picking one out. Ive already heard dire stories about cheap usb power supplies.

Is splitting the data \ power as simple as splitting the cable and splicing onto the appropriate lines? Need to look up the USB spec :stuck_out_tongue:

Thanks again!

4

Yeah, USB has 2 wires for power and 2 for data. You can split them and power the USB DAC separately. You do have to make sure the devices share ground though.