automatic digital input switch

[Willem]

Like many here, I have more digital sources than I have inputs on my DAC (RME ADI-2). So I bought this automatic switch: https://www.tindie.com/products/Beni_Skate/automatic-spdif-opticalrca-audio-switch/ Its only limitation is that the connected source units should turn off their signal when not in use (all but one of mine do). At the time I could only judge its functionality, but not its technical performance. RME's Matthias Carstens has now bought one to try out and is more than pleased about its technical performance: https://forum.rme-audio.de/viewtopic.php?id=29927

 

[Blumlein 88]

Thanks for posting I'm sure lots of us have uses for this, and we never know at low prices if the results are good. Mr. Carstens confirms it can reduce input jitter and has the Wolfson chip for that.

I'm also intrigued one of the options for $19 extra is:
Optional high quality audio DAC (ES9023 24Bit Sabre DAC)

I wonder if that would be a nifty budget DAC?

 

[Willem]

Yes it is a good solution for a common problem, so I am a bit surprised nobody thought about doing this properly before. The version I bought was the basic one because I did not need more, but there are quite a few versions, indeed including one with a DAC. If that DAC is as good as the switch, it may be interesting.

 

[Habu]

Hello from France,
Just to complete Willem’s post:

Automatic SPDIF (Optical/RCA) Audio Switch by Beni_Skate

https://www.tindie.com/products/Beni_Skate/automatic-spdif-opticalrca-audio-switch/

Automatic Optical/RCA SPDIF Audio Switch with Optical/RCA SPDIF Output and additional high quality Audio DAC
Designed by Beni_Skate (Benjamin KERSCHNER) in Austria.

What is it?

• Optical/SPDIF Audio Switch with automatic input detection (it will automatically switch to the input where a signal is coming - if there is a signal on 2 or more inputs the inputs are prioritized - it will always prefer input 1 before input 2 and so on)
• 4 optical inputs and 3 coax inputs (RCA or BNC plugs) or 7 optical inputs
• Optical and/or Coax (RCA or BNC) outputs (coax via RCA/BNC plugs with output transformer)
• Optical output will switch off if there is no signal on any input (so a receiver can switch on/off automatically based on the signal here)
• Optional high quality Audio DAC (24Bit Sabre DAC - like some other DAC shields for the Raspberry Pi)

Why did you make it?

• I wanted to connect TV, Raspberry Pi and Playstation to my 5.1 system via optical cable, but the 5.1 system only has 1 optical input - using HDMI doesn't work well, because the TV forwards 5.1 streams always as 2.0 stream, so you don't have a good sound anymore. So I searched the internet and could only find switches with a remote and no automatic input detection (the only one I found was very expensive and only had 2 inputs).
• Because of my optical audio output/input module for the Raspberry Pi people were asking if it is possible to combine a optical input module and a high quality audio DAC shield - in theory this is possible, but you don't really need a Pi for this - you can connect the audio processor to the DAC and only need something which makes some basic simple controls.
• So I decided to create an optical audio switch which also includes a high quality audio DAC and is controlled by a small microcontroller.

What makes it special?

• Up to 7 inputs (7 optical or 4 optical and 3 coax with RCA or BNC plugs)
• Automatic input detection (no remote or so is needed)
• 2 color status LED for every input
• High quality Wolfson audio processor with 7 inputs to de-jitter and refine the signal (not just a simple digital switch!)
• Full support up to 192kHz/24Bit audio
• Optional high quality audio DAC (ES9023 24Bit Sabre DAC)
• Optical output will be switched off if there is no signal on any input (so it is possible that a receiver switches on/off based on the signal)
• Power supply via Mini USB cable (can be connected to a TV USB port for example, so it switches on and off with the TV) (5V adapter not included - only USB cable if selected)
• Possibility to make software updates via USB on a computer (in case there might be updates)
• Aluminium case (100x80x30 mm)

Automatic Input Detection / Switching Logic
Basically all inputs have priorities (OPT1 has highest priority, RCA1 second priority, OPT2 third ...). If a signal comes up on an input with higher priority the switch will jump to this input immediately. If there are active signals on multiple inputs, the switch will stay on the current input as long as there is a valid signal - if the signal is invalid for some seconds it will check the next active input if the signal there is valid - if the signal there is also not valid it will go on to the next and so on. One happy customer made a quite detailed review: Youtube

Ordering Info

• It will be shipped fully assembled and tested with aluminium case.
• If it is sold out, please just join the waitlist - new boards will be available soon (I have all parts on stock and will assemble the boards based on your request).
• If you have any special requests or questions just contact me.
• For a switch with BNC plugs please write a message to me.

Manual:
https://d3s5r33r268y59.cloudfront.n...019-11-03-15-32-42/Automatic_Audio_Switch.pdf

 

[Habu]

Mr. Carstens confirms it can reduce input jitter and has the Wolfson chip for that.

Full post from the Co-Founder of RME Audio Matthias Carstens (https://forum.rme-audio.de/viewtopic.php?id=29927)

"The 'Automatic SPDIF (Optical/RCA) Audio Switch' from Tindie (link in first post) came quicker than expected. I ordered the version with 4 optical / 3 coaxial inputs and 1 optical/coaxial output.

This unit has one single 'issue' for typical RME users: it doesn't speak ADAT, because it uses a special SPDIF transceiver inside.

Apart from that I am really blown away. This small unit does everything right, works perfectly, and passed all my tests without any problem. It works as true pass-through (24 bit audio data and channel status), supports all main sample rates from 32 kHz up to 192 kHz, and selects the inputs automatically as logical (and useful) as possible.

The one thing that astonished me most: the internal chip, a WM8805, offers jitter reduction in the audio band. The Wolfson data sheet does not talk about that at all. Yes, this thing reduces jitter by at least a factor of 40 where it matters, without the use of a SRC. A very rare feature, even more so for such a device.

SPDIF coaxial starts to detect an input signal at 0.3 Vss, but after locking works down to 0.15 Vss, so is very reliable and compatible. The coax output is transformer-coupled and provides 0.6 V (standard is 0.5 V), just the little bit of reserve that one wants to see and needs in real-life operation. The optical I/Os use DLR/DLT2160, the right ones for successful 192 kHz operation.

All I can say is: Highly recommended! Now the only thing missing is another version with remote control..."