Marcel, do you know what current the RTZ DAC requires fro the power supplies. Of those in the picture, the smaller one is able to deliver 5VDC @ 300mA and the larger +/-15VDC @ 200mA. I can put together another supply that should be good for around +/-15VDC @ 500mA.
Thanks Marcel. I missed that when I skimmed through the thread - I might just get away with the power supplies in the picture.
I see that one of the red film capacitors is bent. I'm not sure if I did that to make the filter board fit a bit better or whether it happened in transportation. The filter board is supposed to go on top of the DAC board, placed such that it is above the red capacitors, but the headers that I used are a bit too short/red film capacitors a bit too high.
Marcel, that cap is qite a bit taller than the other two red ones so you've installed it like that to reduce the height - yes, the headers are a little short but seem to make sufficient contact - I might have been tempted to mount the caps underneath.
I'm currently listening to Marcel's RTZ DAC, a nice DSD256 Vanessa Fernandez recording. It was a real pain to get it playing to start with as the tall red caps on the DAC board mean it's really hit and miss to get the headers connecting properly. At first it sounded a bit edgy so I just left it playing for an hour or so before returning for a proper listen - I'm impressed, it sounds clean and dynamic, well balanced, with lots of detail, not as sweet as the Valve DACs I have available but then it is somewhat compromised being a prototype.
For the input I'm using a JLSounds i2soverUSB board (version 2) interfaced to the RTZ DAC in the same way as the recent Valve DAC project (sorry Marcel, but I soldered a header to the RTZ board to facilitate this). Because the output is balanced I've had to botch a single-ended connection to a 3.5mm headphone jack to feed my Noir HPA.
In my opinion Marcel is to be congratulated on another successful project and I suggest the concept is worthy of further developement. I would be happy to make some suggestions around practical aspects and perhaps there may be some options for better parts, such as the filter stage op-amps, or maybe a valve based filter stage would be worth considering, perhaps using some of the Soviet-era sub-mitiature triodes (I have some I would be happy to donate to a protoptype). Whatever, I would definitely add one to my DAC stable.
For the input I'm using a JLSounds i2soverUSB board (version 2) interfaced to the RTZ DAC in the same way as the recent Valve DAC project (sorry Marcel, but I soldered a header to the RTZ board to facilitate this). Because the output is balanced I've had to botch a single-ended connection to a 3.5mm headphone jack to feed my Noir HPA.
In my opinion Marcel is to be congratulated on another successful project and I suggest the concept is worthy of further developement. I would be happy to make some suggestions around practical aspects and perhaps there may be some options for better parts, such as the filter stage op-amps, or maybe a valve based filter stage would be worth considering, perhaps using some of the Soviet-era sub-mitiature triodes (I have some I would be happy to donate to a protoptype). Whatever, I would definitely add one to my DAC stable.
Well, all good things come to an end; I accidentally bumbed the table and the DAC stopped playing. It's just the header issue but it is so sensitive to positioning the headers!
Marcel, if you're OK with it I think it would be worth unsoldering the red caps and re-insatalling them underneath the board?
Marcel, if you're OK with it I think it would be worth unsoldering the red caps and re-insatalling them underneath the board?
I soldered them to the top side to keep them well-shielded from the data-processing digital stuff on the bottom side. I don't know whether this is really needed, as there is not much data-processing digital stuff anyway.
I really should have used longer headers or less high capacitors. Ray, do you see any way to extend the connection to the filter board by a couple of millimetres?
I really should have used longer headers or less high capacitors. Ray, do you see any way to extend the connection to the filter board by a couple of millimetres?
Hi Marcel. I have some longer headers that would probably do the job but I would have to swap both headers of course. Incidentally, you were right about the red cap, on closer inspection the lead had indeed broken so I had to correct that when I installed the input header - my eyes aren't what they were and I'm having to use magnifiers for fine/small work.
Anyway, good result on your part, apart from the header issue it worked first time and sounds very good. Will you consider further development, if there is interest I would be happy to run another group buy.
Anyway, good result on your part, apart from the header issue it worked first time and sounds very good. Will you consider further development, if there is interest I would be happy to run another group buy.
Do you think you can desolder the present headers? Maybe you can desolder them one terminal at a time if you manage to cut or remove the plastic.
As agreed, I will design and layout a version with fixes for all the discovered bugs and with a way to conveniently switch the polarity of the MUTE and DSDON pins.
As agreed, I will design and layout a version with fixes for all the discovered bugs and with a way to conveniently switch the polarity of the MUTE and DSDON pins.
The headers I have are 19mm long so should do the job. No time for a couple of days though so I'll probably report back next weekend.
Marcel, if I may be so bold, some initial thoughts on developing the RTZ DAC;
- Can we have the option of PCB mounted RCA and XLR sockets on the filter board, like the ones in this image - http://www.soekris.dk/images/dam1941_sys_top_1600.jpg
- Can you include more mounting holes to allow stand-offs to be installed between the DAC and filter boards to stabilise the connection between the two.
- Could there be an option for IC sockets on the filter board to allow different op-amps to be tried (as well as the smd pads).
I can't open the Kicad files: it seems the libraries are not found because the usual "sym-lib-table" and "fp-lib-table" files are missing (or are wrong)...
Might be too early to ask this, but any idea of approx cost?
I've wanted to build a Marcel DAC for a while, but cost deterred me from the Valve DAC.
Randy
I've wanted to build a Marcel DAC for a while, but cost deterred me from the Valve DAC.
Randy
Too early say without a finalised design and knowing if a pick and place build is feasible for finished boards.