Hi Ray,
I went through the same thing, read the few posts starting from here:
https://www.diyaudio.com/community/threads/valve-dac-from-linear-audio-volume-13.308860/post-6401387
Cheers,
Achim
I went through the same thing, read the few posts starting from here:
https://www.diyaudio.com/community/threads/valve-dac-from-linear-audio-volume-13.308860/post-6401387
Cheers,
Achim
Ray, are both MUTE and DSD ON active low now? That is, does MUTE low mean the sound has to be muted and does DSD ON low mean the data are in DSD format? If so, for the raw DSD valve DAC, it should suffice to swap them. In Achim's case, one was active low and the other active high, which complicated things. Achim also used a JLSounds board, but apparently the polarity sometimes changes with the software version.
As the raw DSD valve DAC can only handle raw DSD, it treats its active-high DSD ON input as an active-low mute: when the data are not DSD, it can't process them properly and mutes its output. Similarly, an active-low DSD ON signal goes high whenever the data are not DSD, so you can connect it to the active-high MUTE input.
As the raw DSD valve DAC can only handle raw DSD, it treats its active-high DSD ON input as an active-low mute: when the data are not DSD, it can't process them properly and mutes its output. Similarly, an active-low DSD ON signal goes high whenever the data are not DSD, so you can connect it to the active-high MUTE input.
I had a similar issue with the BBB/Twisted Pear Hermes/Cronus that is use with my DSC2 and solved it with a small additional isolator board so I think I'll look to make use of that. I'll need to modify it as, unlike the DSC2 scenario there are no convenient 3.3V power lines available so I'll have to add some 3.3V regulators, fed from the 5V lines,
As Marcel summarizes - it's a simple and effective solution. Easily breadboarded if you go for a through-hole optocoupler. There seem to be a few on the market. I had a surface mount type which offers an added experience of soldering task.
Yeah, Im in a similar boat with the JLSounds board. Let us know if there's a few option to invert the isolated outputs.
Lyuben has recommended just using an invertor and suggested a part number that will run on a 5V power supply so really a very simple solution. I think I will draw a simple PCB that will interface the JLSounds and Valve DAC headers and include the invertor so it should end up in a simple stack beneath the Valve DAC main board.
The only fly in the ointment might finding somewhere with some stock of the invertor chip.
The only fly in the ointment might finding somewhere with some stock of the invertor chip.
Yesterday I started to design a simple interface PCB and managed to order some of the inverters suggested by Lyuben from Mouser - lucky as they're were all but out of stock with a long lead time. I will try to finish the PCB in the next few days and post an image so another pair of eyes can check/critique it.
Yes I’ve noticed that. I figured I would cross that bridge when I got there and try and get other things ready first. Step 1 is finding a PCB since ordering a new batch for one unit is prohibitively expensive.
Sonny, there was a fellow in the US that I think still had a pcb or two from the group buy. I can't remember his name, but a search should find it. Perhaps he was where your original pcb came from?
Otherwise, I do have spare pcb's, and even a spare FPGA. I managed to sneak an extra pair of TE0630 LX75 from Mouser when things were getting hard to find and I only need one for my second ValveDAC...although a spare would be worthwhile in this current supply situation but realistically I should not need one. They are not programmed. I am in Australia which is a long way from everywhere else, so there would be the cost of international postage but as far as I can tell that FPGA is unobtanium at the moment.
Otherwise, I do have spare pcb's, and even a spare FPGA. I managed to sneak an extra pair of TE0630 LX75 from Mouser when things were getting hard to find and I only need one for my second ValveDAC...although a spare would be worthwhile in this current supply situation but realistically I should not need one. They are not programmed. I am in Australia which is a long way from everywhere else, so there would be the cost of international postage but as far as I can tell that FPGA is unobtanium at the moment.
