Hi
I currently have a 2 deck dddac, and I'm thinking of adding more boards. I just have a couple of questions:
Are there any significant differences between v4.4, 4.5 and 4.7 dac boards?
I'm regularly see people using 2, 4 or 8 deck dddac's. Can any number be used, ie 3 or 5?
Many thanks, Richard
I currently have a 2 deck dddac, and I'm thinking of adding more boards. I just have a couple of questions:
Are there any significant differences between v4.4, 4.5 and 4.7 dac boards?
I'm regularly see people using 2, 4 or 8 deck dddac's. Can any number be used, ie 3 or 5?
Many thanks, Richard
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
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
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
Thanks Matthias, actually this might be a good idea. Will have to look into this and see what time it takes to keep this updated. I see your projects and indeed you put an extreme amount of effort in your documentation 😳
I have a question about Bias trimming, I have put all the deks on 40 mv and now after a week all measure 1.3 mv higher
I had the dac for more than an hour on before trimming
Can it any harm the extra 1.3 mV or can I leave it the way it is now
I had the dac for more than an hour on before trimming
Can it any harm the extra 1.3 mV or can I leave it the way it is now
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?
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
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?
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?
sure, sounds like an excellent choice, if budget allows for it ?
what are you looking for in impedance matching ?
also looking forward to your review of capacitors 😎
what are you looking for in impedance matching ?
also looking forward to your review of capacitors 😎
Hi all,
I had a working dddac (4 stack) - sadly, had being the operative word. I was trying out a new 12V supply, and stupidly, connected the PSU 12V smoothing cap in reverse. As expected, pyrotechnics ensued and "have" became "had".
Where do I start checking? thks.
This is the blue mainboard + black DAC board version 2
I had a working dddac (4 stack) - sadly, had being the operative word. I was trying out a new 12V supply, and stupidly, connected the PSU 12V smoothing cap in reverse. As expected, pyrotechnics ensued and "have" became "had".
Where do I start checking? thks.
This is the blue mainboard + black DAC board version 2
but the 12V voltage you supplied was normal/positive right? and the cap was destroyed? so did you solder a new cap and see if the DAC works?
Or did the DAC had a negative voltage?
if the latter is the case, normally the voltage regulators on the mainboard will be dead. The DAC boards has 4,7Ohm input resistor, so may be the ones on the DAC board survived.
disconnect the 12 Volt wire which goes up into the stack of DAC boards.
Just connect a 12 volt bench power supply with current limit at 0,1A and measure the voltages after the LF33 LF 50 - take it from there
Or did the DAC had a negative voltage?
if the latter is the case, normally the voltage regulators on the mainboard will be dead. The DAC boards has 4,7Ohm input resistor, so may be the ones on the DAC board survived.
disconnect the 12 Volt wire which goes up into the stack of DAC boards.
Just connect a 12 volt bench power supply with current limit at 0,1A and measure the voltages after the LF33 LF 50 - take it from there
You are absolutely right. The regulators were bust. Replaced those, and it's singing again. Thanks for the advice, and also for validating that nothing else may have gone kaput.
Just to add, the supply polarity was correct. Just the cap was wired in reverse. Regulators on dac boards all good - measured 8V and 3.3V. Haven't checked the Spdif input. Will do that. Thks again.
Good to hear the DAXCs are still fine!
yes, check spdif, the WM8804 might have not survived. so fingers crossed
yes, check spdif, the WM8804 might have not survived. so fingers crossed