couple of thing comes to mind...
What is "very low voltage"? play 200Hz 0dB tone and measure with your DMM AC voltage.
check analog voltage (8 Volt?).
You use a transformer? Check things also without transformer.
Use another I2S source, just to make sure. Same issue with spdif as usb source?
check all connections, again and again, for all the commons. are you using more boards? check with one board after each other
things like that, be Creative and try to use the way of deduction.
If all fails, I do check/repair service as mentioned before
Hello,
Just did get the os con from mouser Parts are coming in on a regular basis now.
Tinght will order the 100nF kemet pps to use instead of the 100nF wima. Can anyone tell which of the 100nF should be changed into PPS type. A photo of the board with some colour indicating the type of cap would be nice. Once they are all connected together i would not have the guts to start changing caps. Greetings and thanks in advance, Eduard
Just did get the os con from mouser Parts are coming in on a regular basis now.
Tinght will order the 100nF kemet pps to use instead of the 100nF wima. Can anyone tell which of the 100nF should be changed into PPS type. A photo of the board with some colour indicating the type of cap would be nice. Once they are all connected together i would not have the guts to start changing caps. Greetings and thanks in advance, Eduard
PPS Cap location Recommendation
Yes, all on the mainboard and all on the digital side of the PCM1794 board and none on the analog side. I don't know which mainboard you have, but if it has a clock-PS circuit - use the provided caps or high quality ceramics there. Buy the narrowest PPS 100nf caps to fit above the data delay IC's.
I agree that it is much easier to use the upgraded parts on the first build. Everyone who reported using PPS caps felt that they heard a small sq improvement - no regrets.
Yes, all on the mainboard and all on the digital side of the PCM1794 board and none on the analog side. I don't know which mainboard you have, but if it has a clock-PS circuit - use the provided caps or high quality ceramics there. Buy the narrowest PPS 100nf caps to fit above the data delay IC's.
I agree that it is much easier to use the upgraded parts on the first build. Everyone who reported using PPS caps felt that they heard a small sq improvement - no regrets.
OK I feel like I am getting somewhere, possibly not in the right direction though?
I checked the voltage from the power supplies and they where both a little low, not sure how as I had done this a number of times in the past?
installed all usb driver and foobar 2000, played a bit of music but absolutely no sound apart for that coming from the computer, I will have a look at the settings again tonight to check its all set up right but don't think it is all fine.
With a computer plugged into the DDDAC I get a power and host active light but I also get a 48khz light which stayed on even without the computer plugged in, don't think this is right?
Analogy output now reads 1.37v 1.412ohm (right channel) 1.38 1.425ohm (left channel). At the s/pdif I am getting .75ohm 19milli volts.
I measured the other side of the dac boards and getting 2.44v at BCK 4.99v at DAT and 2.49v at LR but DAT voltage disappears when switching to spdif.
If no one has any ideas from this I can de-solder the cinemags and check everything again.
Many thanks
I checked the voltage from the power supplies and they where both a little low, not sure how as I had done this a number of times in the past?
installed all usb driver and foobar 2000, played a bit of music but absolutely no sound apart for that coming from the computer, I will have a look at the settings again tonight to check its all set up right but don't think it is all fine.
With a computer plugged into the DDDAC I get a power and host active light but I also get a 48khz light which stayed on even without the computer plugged in, don't think this is right?
Analogy output now reads 1.37v 1.412ohm (right channel) 1.38 1.425ohm (left channel). At the s/pdif I am getting .75ohm 19milli volts.
I measured the other side of the dac boards and getting 2.44v at BCK 4.99v at DAT and 2.49v at LR but DAT voltage disappears when switching to spdif.
If no one has any ideas from this I can de-solder the cinemags and check everything again.
Many thanks
Carl,
I have my amps done and want to move to this Dac project after hearing yours.
Need some direction and want to pick your brain. If you and mark have some time, let's get together.
did you play music on spdif? no need to measure DC on digital lines, you always get values like that which are meaningless. I asked you to measure the Supply voltages, what are they? and some thing else, how did you connect the Cinemags? Which colors goes to what PIN at the dac board? or post a clear picture showing it. thx
Yes playing through the CD player I get around 10th of the volume than normal
Volts comming from the power units are 12 and 5v, the 5v goes to the USB board and mesures 5v at the input, the 12v goes to the Dac boards and mesures 12v at the input.
The Cinemags are wired up as follows:
Orange - Spdif ground
Yellow – Spdif central pin
Brown – analog out negative
Red – analog out possitive
Black and white – chasse (ground)
Attachments
Also...
Building a 4 stack DAC this time so for the I/V resistors as assume 33 ohm will be fine?
I am looking for a greater output from this DAC so I assume 4 stack will improve this from my 2 stack DAC I have today?
I am using the cinemag transformers too so anything else to increase the DACs output?
Thanks
Building a 4 stack DAC this time so for the I/V resistors as assume 33 ohm will be fine?
I am looking for a greater output from this DAC so I assume 4 stack will improve this from my 2 stack DAC I have today?
I am using the cinemag transformers too so anything else to increase the DACs output?
Thanks
Hello ,
That is why i started a new thread ! i think they are used between the nut and the stand off that mounts the dac board to the mainboard. The pictures on the audio creative are not that clear but i think you can see them being used.
By the way did get a message about the 6 Kohm resistor and the 2K trimmer.
In the picture that Doede did post some time you can also see the washers
Greetings, Eduard
You could copy and paste this message to the new thread.
Attachments
I think I know what you mean, but does not Spdif means the RCA output connector. it is de digital input from your main board connecting the digital output of a CD Player... did you try that?
also the picture is not the best looking at connections. Where is thick green wire going to (connected to "common")?
I strongly recommend to disconnect the Sowters, so you have a basic set up and measure DC voltages at the output (POS verus Common and NEG versus common) and also the 8volt DC supplying the dac chip. Not the 12 volt and 5 volt. I need to know if the dac chips gets 8 volt. You measure this after the conductors (the one under 45 degrees close to the outputs)
Simon, regardless of the number of boards, the output voltage will always be the same... If you need more output voltage, you can use a transformer output between POS and NEG. this will double the output. The Sowters quadruple the output by the way... Thta is the ONLY way to do it.
Hello Simon,
My Sowthers are still in transit. My first dddac will start with the Sowthers.
My Vietnamese audiophile always like to throw in transformers so i guess once they hear my reports the Sowther will be out of stock.
However still wondering how to make it possible for them to hear a dddac. Maybe buy some boards from someone who decided to upgrade to the new ones.
My dac will be to big. Just get a motherboard with 4 decks so they will have an idea what to expect. They can make a LCLC power supply easily because i will bring some LL2733 400mH 1,7 A chokes that one of them will use for his arch nemesis power supply.
Greetings, Eduard
My Sowthers are still in transit. My first dddac will start with the Sowthers.
My Vietnamese audiophile always like to throw in transformers so i guess once they hear my reports the Sowther will be out of stock.
However still wondering how to make it possible for them to hear a dddac. Maybe buy some boards from someone who decided to upgrade to the new ones.
My dac will be to big. Just get a motherboard with 4 decks so they will have an idea what to expect. They can make a LCLC power supply easily because i will bring some LL2733 400mH 1,7 A chokes that one of them will use for his arch nemesis power supply.
Greetings, Eduard
Hi Edward,
Sounds like a plan and I have some older boards and fully built DDDAC here which I am happy to sell if you need them. Send me a PM
Cheers
Simon
Evening all. Just to let you know my dac is now up and running!!! after a very interesting evening at dwjames place yesterday evening. Turns out I had missed a couple of resisters, which I think regulated the power on the dac boards, and the resisters between the ground and live on the RCA's where the wrong value.
The only down side to the evening was that I got to listen to an incredible system which I fell in love with! Now have to work out how to best to change the rest of my system to emulate it.
Thanks again for everyone's help on my very long and rocky road!
Sorted
Very welcome!. That was an interesting little puzzle for my tired brain, but as with most of these things it's simple once you work it out. To clarify, it turned out that one of the decks had no pin CCS 6k resistors fitted, so we swapped in the test 2SK246Y I had lying around and this doubled the output, but still to only about 20% of normal expected volume.
But now there was normal volume output from the dac when we tested direct from pos/neg but not from the output of the cinemags. Turns out the load resistor across the rca plugs was about 1.5Mohm each for some reason. With these snipped out, normal service was resumed and the music flowed very nicely
Long live the DDDAC!
Has anyone built up with the new boards yet?