A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input)

Most revisions were small changes in layout and silkscreen or better placement of components or better holes for example…. So technically they are all the same… and interchangeable without any problem
Is there a table / list available that provides an overview of the changes?

I am asking because I just bought a few second-hand DAC boards and both the seller and I were not exactly sure what the version numbers really mean. The boards in question were version 4.4 and 4.5, but a complete overview showing all versions / revisions would be great.
 
Sorry there is no table for this - as mentioned before, after the On Board Tent Versions, it is only silkscreen and some layout adjustments. Technically they are all the same and can be used in the mix, even with the first generation boards. I know someone did it and liked the mix of two MK1 and two PBT (Powered By Tent)

For the MK3 it might be a good idea to have these available (Changelog) - I will update this in the vendors post #1
 
I case of the 4.4 and 4.5 there is a small difference. The 4.4 still had an option (for testing purpose) to install the 6k resistor for the pin 20 bias, instead of using the CCS with the JFET. In 4.5 this was omitted.

so, if on your 4.4 board there is the CCS they are 100% the same as the 4.5 - If for whatever reason the CCS is removed and the 6k installed they are different
 
I am in the process of adding more dac boards to my 2 board dac, and also want to experiment with some different output caps. I just have a couple of questions.

Someone advised me in a previous post when I when from single board to 2 board, I could decrease the value of the output cap. I haven't seen this discussed elsewhere, is it right/recommended?

While buying some secondhand dac boards, I have ended up with a spare mainboard and spare 12v psu. In order to make direct comparisons between different output caps (and possible other mods), I thought I could set up 2 systems in parellel connected to different line inputs on my preamp allowing quick switching between the two. My question is, I only have a single WaveIO board, if I make up a 3 way ribbon cable can this feed 2 dddac's? If so should the ribbon cable be kept as short as possible?
 
Decreasing the output cap with more boards is not correct. The only thing important is the input impedance of the next stage… this value and value if the cap will give you the -3dB low frequency roll-off point. f= 1 / (2piRC)

there is no problem daisychaining the boards, BUT as the 10 pin header is feeding the 5V to the isolator of the WaveIO, you need to disconnect that part of the cable at the second board. If not, you will connect both 5 volt regulator outputs and short them together. That is not advised. Always good to keep things short, but it will work fine even when it is like 30 can long. Avoid running meters of flatcable
 
Thanks for that Doede, I look forward to experimenting. I'm still a bit confused by impedance matching, but I will read up more on this now.

One more question on a more practical note, I need to buy some more link wire to connect the dac boards. I've seen 0.8mm 99.99% round silver wire available from wires.co.uk, is this a good choice?
 
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