Zero Volume

Rud31

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I have been using a Raspberry Pi 4 (4GB version) as a PiHole Machine, Plex Media Server, Deluge Seedbox and SAMBA Network drive. Seeing how people had been using RPi for audio streaming too and made a viable business out of it, I wanted to try something similar yet different myself.
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I was looking for creating a Balanced Streaming Setup. For that, I had everything; Balanced DAC, Balanced Amps but a Source was still missing. Was confused between Mi Box 4K, WXC-50 or something RPi based. As already had a RPi 3B+ and Zero W with me, decided to go for something unique and ultra-portable. Besides this other reasons for such consideration were:
  • Small Physical footprint
  • Very Low Power Consumption
  • Singular solution for WiFi and Bluetooth based streaming
  • High Customization potential
Recently I got CA DAC MagicPlus. Besides the USB type B input, it also has a Type A port to connect the BT100 module. This gave me the idea that as Pi Zero has 2 Micro USB ports, one for Data and one for Power, it looked like a perfect fit. SO first thing first, I loaded Volumio in a MicroSD card, created the ssh and wpa_supplicant config files in boot partition for better control as I was going headless and wanted to keep avenues for more granular access open.
Upon initial boot-up, it was a normal Volumio setup, configured the Network share in Volumio and also assigned the MAC of Pi a Static IP in Network Router's table.
Now came the Trial and Error part.
As the Data port of Pi Zero is capable of powering the board too, first try was to connect the Pi's Data port with DAC's USB input port. No Dice. Pi didn't power up so guess the Type B input port of DAC is Data only.
In next attempt, connected the Power port of Pi with DAC's Ext port and the Data Port with USB input port of DAC.
Pi did boot up but Volumio didn't recognize the DAC, even though the DAC is in USB DAC Compatibility list of Volumio. SSHed into Volumio and ran lsusb -t and aplay -L. Neither the USB device was listed nor did ALSA listed any compatible hardware. Thought it to be some config error so decided to pause it and hit the hay.
Next morning tried it again but this time with a different Micro USB OTG adapter.

Voila! Volumio recognized the CA DAC and Audio was streaming from Network drive to it without any issue. In Bubble UPnP, Volumio was showing up as UPnP Renderer so was able to stream music from my Android phone to Volumio to CA DAC. Didn't try the Bluetooth streaming but I'm optimistic that it too would work.


Now as this "jerry-rigged setup" doesn't bodes well for cables and connectors involved, I decided to use a Customized USB Type A board for Pi Zero which provides a full sized Type A male port replete with Power and Data lines as it taps into both from the Pi board. While this provides a direct and better connection of Pi Zero to Ext port of the DAC, getting the Data out from Pi to the DAC still required connection from Micro USB port to type B input port through various adapters/dongles.




As a proof of concept, it worked. In next phase, to make it practically viable, I intend to solder the GPIO headers and go for a Digi ZERO Hat and feed DAC with Optical signal from HAT. Currently sourcing this HAT is an issue as it's available only with Element14 and I have no GST ID. An Element14 authorized reseller FidesElectronics has it in stock but don't know if it can trusted. Moreover Fides have shifted to new domain, Components4u.in and have listed a Whatsapp contact number so will talk to them to work something out.
In phase 3, I will try to see if providing cleaner power to both Pi and DAC from a powerbank have any improvement in SQ. Along with this I will try to have a Hotspot based streaming in Volumio so that it can be a truly wireless streamer, capable of operating in even no network scenario(such as in my village where there is no WiFi).
Will keep posting updates.
 

Rud31

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Rud31

Active Member
Joined
Oct 4, 2018
Messages
215
Points
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Location
Haryana
So the DigiZero board arrived, bought an Amazon Basics Optical cable too. Slapped on the HAT to Pi Zero. Now the increased height of the Pi made it impossible to directly jack it into the "External USB" of the DAC so used an USB extender cable to draw power from the DAC. The Optical cable was a non-issue for fitment concerns. The Volumio OS however didn't pickup the NAS. After deleting the NAS configuration and rebooting the Pi, did an automatic scan of network for NAS from Volumio. It picked up the drive, modified few parameters and it was good to go.
Music streamed,ears soothed,eyes moistened, relief sighed !
Next up, streamed music stored on Phone to Volumio through Bubble UPnP. That also worked.
Next test phase will involve the power source permutations and streaming in adhoc conditions i.e. using Volimo's own hotspot instead of a WiFi network. Pi Zero W has Bluetooth but AFAIK Volumio doesn't supports Bluetooth streaming in "Free version".
 

bloredude

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@OP, good work!

I am wondering why do you call this a "Balanced Streaming" setup? What aspect of this arrangement makes it a Balanced Source?
 
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premoddev

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So the DigiZero board arrived, bought an Amazon Basics Optical cable too. Slapped on the HAT to Pi Zero. Now the increased height of the Pi made it impossible to directly jack it into the "External USB" of the DAC so used an USB extender cable to draw power from the DAC. The Optical cable was a non-issue for fitment concerns. The Volumio OS however didn't pickup the NAS. After deleting the NAS configuration and rebooting the Pi, did an automatic scan of network for NAS from Volumio. It picked up the drive, modified few parameters and it was good to go.
Music streamed,ears soothed,eyes moistened, relief sighed !
Next up, streamed music stored on Phone to Volumio through Bubble UPnP. That also worked.
Next test phase will involve the power source permutations and streaming in adhoc conditions i.e. using Volimo's own hotspot instead of a WiFi network. Pi Zero W has Bluetooth but AFAIK Volumio doesn't supports Bluetooth streaming in "Free version".
Try MoodeAudio, bluetooth is free.. there is no subscription involved for any features.
 

Rud31

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@OP, good work!

I am wondering why do you call this a "Balanced Streaming" setup? What aspect of this arrangement makes it a Balanced Source?
What you see is a test bench configuration. The actual setup where it would be used is in my village, in a room 20 ft x 15ft, having 2 Crown XLS amps(1502 for Highs and 2502 for Subwoofer), all connected through UGreen XLR cables. Highs are handled by Elac Debut B6.2 and subs are 2 12inch JBL subs in a 3 cubic feet slot ported box.
Try MoodeAudio, bluetooth is free.. there is no subscription involved for any features.
Thanks for the suggestion, will look into it.
 

bloredude

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Okay, that doesn't answer my question about the streaming and the source being balanced. What you described sounds like what is generally call a bi-amplified setup. May be there is something about the terminology being used here that I can't understand. Or may be there is something more you can add to clarify!

Are you feeding the two amps two different signals? If yes, are they both full range signals, or separate signals for bass and full range amps? Who/which component does the splitting of signals?
 

Rud31

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Okay, that doesn't answer my question about the streaming and the source being balanced. What you described sounds like what is generally call a bi-amplified setup. May be there is something about the terminology being used here that I can't understand. Or may be there is something more you can add to clarify!

Are you feeding the two amps two different signals? If yes, are they both full range signals, or separate signals for bass and full range amps? Who/which component does the splitting of signals?
OK let me explain my chain.
Pi Zero/Phone acts as Digital source. The signal/data is fed to CA DAC Magic Plus through either a USB input or Optical input. The Analog audio signal is taken out from XLR outputs of DAC and fed to XLR inputs of Crown XLS1502. Link port of Crown 1502 amp is used to pass signal to other Crown 2502 amp using a Stereo Quarter inch to XLR cable to XLR inputs of the 2502. Thus a fully balanced setup,AFAIK.
Bi-amplified setup involves 2 amplifiers powering a single pair of speakers, where 1 amplifier is driving tweeters and other amp is handling Woofers. In my setup, I'm feeding the Elac Debut B6.2 speakers from Crown XLS 1502, with High Pass filter set in the amplifier itself at 80Hz while the Subwoofers connected to Crown XLS2502 amplifier has Low Pass filter set at 80Hz. Thus the resultant chain is Balanced and has theoretically no physical distortion due to drivers being driven beyond their limit.
See/Read up on features of Crown XLS amp for more clarity on how I'm doing it if my explanation isn't lucid enough.
 

bloredude

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So, the "balancing act" is being done by the Crown amps :) It's clear now!

I was fully focused on Pi here, thinking how are you making it do balanced streaming. My confusion lied with the source setup.
 

Rud31

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In Volumio, made the change to start its own access point in case it doesn't find any Wi-Fi network. Coupled that Bubble UPnP/Hi-FiCast on Android, it made for a nifty local media streamer.

The wiring pic shows the "Balancing" act
 
Perfect for audiophiles wanting both excellent music quality and flexible operation.
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