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Sensible tweaks to an RPI4 based streamer?

RichardA

pfm Member
I recently repurposed an RPI4 to use as a streamer.
(It was originally bought as a general IT project for my kids who sadly lost interest all too quickly)

I’ve put Volumio on a new micro SD card and am controlling the RPI4 with an app on my iphone. It’s connected to WiFi and streaming Spotify. I’ve got a modest supra USB lead to connect to the digital input on my Rega Isis.

Sound is good enough for background listening and researching new music but inevitably I am wondering whether there are tweaks to improve things a bit (higher frequencies are quite ragged).

For example I use the standard RPI wall wart and I see there is a burgeoning cottage industry in linear PS units. I have also seen supposedly better SMPS - allo nirvana? - though perhaps the better PS solutions are more effective on standalone DACs.

Regardless I want to limit myself to a modest spend.

Any suggestions?
 
Best way to improve sound from a Pi is to use one of the HATs. A little board mounted on top of the Pi containing either a DAC or a clean interface to an external DAC. My favourite Pi combination uses the Allo Digione board to give a clean Coax signal to an external DAC I also have had good results from the IQAudio Pi DAC that gives RCA outputs. My favoured software is Picoreplayer.
https://uk.pi-supply.com/collections/iqaudio
https://allo.com/sparky/digione-player.html
 
@RichardA
I am far away from being an expert on these matters, but have been running a Pi4 streamer for about a year now.
I started with Dragonfly DACs into a spare USB port, then to an Allo Boss DAC HAT (v1.2). At this point, I switched to an external DAC (Schiit Modi 3, mainly due to John Darko’s videos) and then out of the blue, a Schiit Modius became available. With both Schiit DACS, I was USB/USB.

About a month or so ago, a member on another forum was selling an Allo Digione Signature HAT, and although I don’t think I could have justified spending the money on a new one, a used example was within budget. I had an optical cable made up and so my current streamer is Pi4 with said HAT>optical>Schiit Modius>Rega Brio.

Apologies for the above meanderings but the point I wanted to make was that at each stage and at each “upgrade”, I believe that I have achieved an improvement in overall SQ. Unlike many others, I seem to have a real issue trying to describe what I’m hearing in a way that seems to make any sense. What I would say, though, is that to my ears, some of the changes have been very slight, barely noticeable to me (e.g. move from Dragonfly Black to Red), but the biggest single improvement to overall SQ was when I plugged in the Allo Digione Signature board.

If you would find it helpful, I can try and explain what I think has changed but my description may be a bit “woolly”.

Other things;
I have separate power supplies for my Pi (standard SMPS), my HAT (I am using a separate 5.2v SMPS from an old router) and battery to my DAC. My HAT has 2 power inputs; a “clean” side for the HAT and “dirty” side for the Pi. Like you, I have read so much about potential improvements with LInear PSUs but haven’t moved on this yet. I’ve been looking at the Allo Shanti but it may be a bit big for my cabinet.
I started with Volumio and now use Moode. Happy with both, but have stuck with Moode for 6 months now.
I realise you have an ISIS and I only know what I’ve read about this fantastic bit of kit. Obviously, comments about my DACs almost certainly won’t be of any relevance to you as I’m guessing the DAC and DAC implementation inside the ISIS will be far and away in excess of anything I can ever afford. But my undoubted (or is it just perceived??) SQ improvement that I’ve achieved by bringing in the Allo Digione Signature may just be of some help.
And I do realise that there are less expensive SPDIF HATs available, both from Allo and other manufacturers. I have read plenty about these, but no first hand experience.
 
Your ISIS only has a USB digital in do you have another DAC that takes CoAx/Toslink?

Be an idea to define the budget.

If limited to USB connections only then Allo do a USB Sig board and various PSUs, all good kit.
https://allo.com/sparky/usbridge-signature-pcb.html

If you have CoAx I like the Allo digital hats, another to look at is HiFiBerry. If looking to minimise spend the Digi+. Go CoAx to your DAC.

https://allo.com/sparky/digione-signature.html

https://www.hifiberry.com/shop/boards/hifiberry-digiplus-standa
 
I used a HifiBerry Digi+ Pro HAT (costs about €35) on my Pi3B which allowed it to feed a cleaner signal via coax or toslink into my DacMagic 100. I was extremely impressed with the sound quality of this combination with CD rips and Tidal streaming. I've just recently replaced the Digi+ Pro with Hifi Berry's DAC2 HD HAT (€90) and this equals the sound quality of the previous set up, but with one less box and 2 fewer cables. My Naim CDX is pretty much an ornament now.

I have another thread open here about PSUs for the Pi and have just ordered an Allo Nirvana.

Pi upgrades are very good vfm.
 
Many thanks for the replies. V helpful.

I have assumed that adding a DAC board attached to the RPI (a HAT?) is unlikely to outperform the DAC in the Isis. (The Isis only has a USB input so flipping to Optical or Coax isn’t an option.)

However reading the comments so far it looks as though there may be HATs that aren’t DACs - instead they are some kind of upgraded USB outputs. If my understanding of that is correct then that sounds promising (though it does mean I may have to discard the existing aluminium case for the RPI which is too snug.

Budget-wise I want to keep upgrades to the low hundreds.
 
There are DAC Hats that give you analogue out and Digital Hats that give you just 1s and 0s.

The Allo USB Signature in their Aluminium case and Nirvana or Shanti PSU would be my choice. You can buy it ready built or just the bits. I have the case version which also takes the Digione Sig board in it too.

The Allo USB board uses the small Pi compute module so no need for your Pi 4, you could sell it.

As well as Allo direct Audiophonics was a good source pre Brexit
https://www.audiophonics.fr/en/case...ure-allo-digione-signature-black-p-14127.html

This is the case I bought to fit both boards into.




 
I have assumed that adding a DAC board attached to the RPI (a HAT?) is unlikely to outperform the DAC in the Isis.

I wouldn't necessarily jump to that conclusion. Why not keep an eye out for a good used DAC hat in the classifieds and try it? If you just keep playing with different USB options into your built in DAC you won't ever know if your DAC is the limitation.
 
I wouldn't necessarily jump to that conclusion. Why not keep an eye out for a good used DAC hat in the classifieds and try it? If you just keep playing with different USB options into your built in DAC you won't ever know if your DAC is the limitation.
If the existing Pi case has room be worth a shot, you’d expect the DAC in a £6K Rega would be the better option though, dunno why Rega didn’t put CoAx/Toslink in as well as USB on the ISIS.
 
If the existing Pi case has room be worth a shot, you’d expect the DAC in a £6K Rega would be the better option though, dunno why Rega didn’t put CoAx/Toslink in as well as USB on the ISIS.
It will be a lot cheaper to play with different DAC hats than to try to massage a USB only DAC with expensive reclockers/galvanic isolators/other BS.
 
If he wants to use the Rega ISIS DAC, maybe it’s the valve version he has and likes and not bypass it then USB is the only option though.
 
There are DAC Hats that give you analogue out and Digital Hats that give you just 1s and 0s.

The Allo USB Signature in their Aluminium case>...........
I haven’t any experience of the USB signature but have read a fair amount.

If I only had USB as an option and was determined to see if there was something “better” than what I already had (and could afford to do so), then I would probably have given the USB Signature a go at some point. Just to prove to myself - one way or the other.

Just to take things a little off track if I may, and for this we need to assume that the DAC in the ISIS is first rate, could it be an idea to see how the Pi is performing (using existing USB and the ISIS DAC) by taking known CDs, creating FLAC files, copying them to a USB stick and plating them via the Pi, with A/B comparison to the same CD?

this would at least show up any deficiencies or shortcomings between the Pi and CD output on the ISIS and may be a useful exercise to help plan the way forward?

Apologies if you’ve already thought about this and discarded the idea.
 
Before splashing out on DAC/Digi add-ons it would be worth checking whether you have maximised the USB option from within Volumio.

I use Moode and have bumped up the USB output on a standalone RPi quite noticeably by simply tweaking some of the settings.
Would have to plug it in again to check exactly which but from memory I definitely increased the buffer size and this made the biggest difference in terms of minimising stuttering and raggedness. I think I also set SOX resampling to 24/96 (but this is what I would need to check)

In terms of DAC HATS I find IQaudio very good - I tried Allo Boss and found no improvement although costing nearly twice as much.
I have also used Justboom and this was also adequate if edged by the IQaudio DAC.
I have yet to try and alternative PSU and use one of the Raspberry own brand - noting that these supply 5.1v which is apparently critical ( YMMV )
 
I haven’t any experience of the USB signature but have read a fair amount.

If I only had USB as an option and was determined to see if there was something “better” than what I already had (and could afford to do so), then I would probably have given the USB Signature a go at some point. Just to prove to myself - one way or the other.

Just to take things a little off track if I may, and for this we need to assume that the DAC in the ISIS is first rate, could it be an idea to see how the Pi is performing (using existing USB and the ISIS DAC) by taking known CDs, creating FLAC files, copying them to a USB stick and plating them via the Pi, with A/B comparison to the same CD?

this would at least show up any deficiencies or shortcomings between the Pi and CD output on the ISIS and may be a useful exercise to help plan the way forward?

Apologies if you’ve already thought about this and discarded the idea.
Digital needle drop :)
 
However reading the comments so far it looks as though there may be HATs that aren’t DACs - instead they are some kind of upgraded USB outputs. If my understanding of that is correct then that sounds promising (though it does mean I may have to discard the existing aluminium case for the RPI which is too snug.

Budget-wise I want to keep upgrades to the low hundreds.

People were assuming you had optical/co-ax input, I don't know of any RPi HAT offering USB out.

Some ideas (varying cost/tweakiness/effectiveness):
- PSU upgrade to Allo Shanti or Farad Super 3 if you want to spend in the not-so-low hundreds
- USB cleaner (e.g. iFi iDefender+ https://ifi-audio.com/products/idefender-plus/ can also be used in conjunction with the Shanti to supply a clean 5V line, Holo Audio Titanis USB dongle)
- Try alternative USB sources e.g. up-to-date smartphone with USB out (with OTG USB C to female A cable) and USB Audio Player Pro or any computer
- Tweak RPi software and/or OS (e.g. Gentoo Player which allows use of alternative Linux kernels)
- Try different USB cables
 
..re: the USBridge Sig, decent unit (still have one knocking about, will shift soon) but that amounts to buying a new streamer...you can't put the RPi4 in it.
 
Would have to plug it in again to check exactly which but from memory I definitely increased the buffer size and this made the biggest difference in terms of minimising stuttering and raggedness. I think I also set SOX resampling to 24/96 (but this is what I would need to check)

Have now checked and I did indeed boost the buffer to 10000 KB and set SOX resampling as specified ...

Incidentally, this improved the USB output quite significantly on my RPi 2B - from what I've read the USB output on the RPi 4 has undergone a redesign and is already apparently much improved compared to the older models.
 
Have now checked and I did indeed boost the buffer to 10000 KB and set SOX resampling as specified ...

Incidentally, this improved the USB output quite significantly on my RPi 2B - from what I've read the USB output on the RPi 4 has undergone a redesign and is already apparently much improved compared to the older models.
The USB bus is no longer shared with Ethernet on the newer models.
 


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