The outer ring of the RCA connects directly to the audio GND of the DDDAC board, no capacitor in between. Make sure the RCA GND is not shorted to the chassis. On the old DDDAC boards, the audio GND was labelled as "COMMON", and it may be the same label on the new version. Also make sure the DDDAC audio GND is not shorted to the chassis. A ground loop breaker connected between audio GND and the chassis may be a good idea.
I used both the Sowter "special DDDAC" and the Audio Creative "gold", but I never compared them one-to-one. All I can say is that they both worked well 🙂
I have a pair of the Audio Creative "gold" transformers, which I don't use. Shoot me a PM if interested.
Thanks for the help. I'll try changing it today and see if I can get audio. I also wired it so that the dac board is grounded through the power supply. Is this correct?
It depends. If the power supply "zero volt" is connected to the chassis, that will tend to cause issues with noise/hum. I really recommend the article on grounding by Rod Elliott (see link in my previous post). Once you understand the difference between audio/GND and chassis-earth/safety-protection, things become a lot clearer.
Well... here are my experiences:
I built the DDDAC1794 Mk.3 and populating the pcb was an extremely easy job. The kit was complete and just to be sure I measured all components before I soldered them to the board. The manual is quite extensive and all steps are described in detail and clear pictures are provided, so many DIY audio enthusiasts should be able to build it. This board is extremely well-made and inspires great confidence in the work of its designer.
As discussed in the above post as a reply to my post #75 I needed to modify Ian Canada's LifePO4 supply first. I have been extremely pleased with this battery supply for quite a few years now and wanted to continue using it for the new arrival, the DDDAC1794 Mk.3
I modified the LifePO4 supply to provide 3.3V for the digital supply of DDDAC but connected it to the 3.3V OUTPUT of the on-board regulator of DDDAC, thus effectively bypassing the on-board regulator. The 9.9V supply (3 x 3.3V batteries in series) was connected to the analog supply 9V INPUT. This was my initial idea and Doede confirmed that this was a feasible way to power the DDDAC (post #76). The LifePO4 was easily modified by changing a few wire links on the bottom of the pcb.
I connected the two supplies to the DDDAC and since there was no smoke I measured supply voltages and the output dc voltages. Then the DC bias current of the DAC chips was adjusted. This is easily done and I managed to adjust them all to the required voltage within a few microvolts. So far so good. I connected the I2S input to my FifoPi and played some music.
Well... quite a surprise: beautiful music. I deliberately say: MUSIC, because the musicality of this DAC manifested itself in the first few days of listening. Not a hi-end sound, not an audiophile sound but MUSIC, real musicians playing their instuments or using their voices. No unnaturalness here. No 'digital' sound but a very pleasant 'analog' sound from this DAC. Mind you, I have been listening to Non-Oversampling DACs ever since I bypassed the Over-Sampling chip in my good old TDA1541 equipped Marantz CD player in 1995 or so. Somewhere in 2012 I added a commercial Sabre ESxxxx DAC to go with my RPi3 and Isolator/Reclocker. I was fascinated by the sound at first, but some time after that I discovered that I did not like listening to this setup very much. I somehow lost interest. I got more listening satisfaction from the CDs played on my Non-Oversampling CD player, to which I had added a tube output stage sometime later.
In 2018 I built an RPi based streamer with a (yes) Non-Oversampling R2R DAC. I had become accustomed to this NOS analog-like sound for quite some time, but the new DDDAC1974 Mk.3 managed to extend this experience one step further. A clean musical, or should I say 'musician's' sound. Real and tangible with black backgrounds and lots of micro detail to enchance the experience. Thank you Doede.
Kind regards,
HenryJazz
Thank you very much HenryJazz for the report of the power supply use and also on your music experience. Did you try (even if it is just for fun) to use the 4 Volt input and let the regulator do the 3.3V? as the minimum dropout is only like 150 - 200mV you could connect the Lifepo power supply ater the "4V input" and still have enough voltage left over for the digital side to work properly. Same goes for the analog side where you could trim your power supply to 8 volt (is dat even possible?) and connect to the "8V output"
best regards
doede
best regards
doede
Winter seems to be the time where people build DACs (or other audio gear 😎)... I have seen an unexpected surge in demand for the DDDAC1794MK3 kit at the webshop from " Audio Creative " (the Duch company who sell the kits)
You might encounter that the DAC kits are "sold out" currently. The PSU kits are still available. But no worries. Next week I will send parts and PCB to the SMD assembly service and kits will be put together. So, I expect kits to be available beginning to mid-March.
You might encounter that the DAC kits are "sold out" currently. The PSU kits are still available. But no worries. Next week I will send parts and PCB to the SMD assembly service and kits will be put together. So, I expect kits to be available beginning to mid-March.
As you can read in this thread I built the DDDAC1794 Mk.3 a few months ago. I am extremely pleased with the build quality and the quality of the sound.
At first I used an output capacitor to test the DAC. I used this Siemens MKV (0.6uF) capacitor for about 6 weeks and then replaced it by another paper-in-oil of DDR vintage. The first one had already been used and was therefore well burnt-in, the second took a while. The sound was very pleasing.
Then I wanted to use the DAC output transformers that I had lying around from a previous DAC build. After making the necessary connections, I experienced horrible distortion and really awkward sound. Obviously something was very wrong!
After long and tedious checking, altering and re-checking I contacted the designer Doede Douma by email and asked for help. Doede is also on http://blog.dddac.com/.
After some emails back and forth Doede asked me to send a picture of the board. He immediately responded: I had omitted one of the two Rload resistors. A really bad mistake! My fault, of course, but Doede was kind enough to respond to my emails almost instantly. Thank you very much Doede.
From then on it was very easy. I soldered the resistors and hooked up the output transformers. A glorious sound! It is too early to talk about the differences between capacitor loaded and transformer loaded 1794 outputs because that takes an extensive period of serious listening. I am in the middle of that now.
Dear Doede, You have not only designed a superb diy DAC, which is easy to assemble and versatile enough to be used with vaious power supplies and most of all extremely good sounding, but you take the time to help out your customers when they need help. And... RTFM!
Designer, manufacturer and help-desk, all in one person! Thank you!
Kind regards
Henry
At first I used an output capacitor to test the DAC. I used this Siemens MKV (0.6uF) capacitor for about 6 weeks and then replaced it by another paper-in-oil of DDR vintage. The first one had already been used and was therefore well burnt-in, the second took a while. The sound was very pleasing.
Then I wanted to use the DAC output transformers that I had lying around from a previous DAC build. After making the necessary connections, I experienced horrible distortion and really awkward sound. Obviously something was very wrong!
After long and tedious checking, altering and re-checking I contacted the designer Doede Douma by email and asked for help. Doede is also on http://blog.dddac.com/.
After some emails back and forth Doede asked me to send a picture of the board. He immediately responded: I had omitted one of the two Rload resistors. A really bad mistake! My fault, of course, but Doede was kind enough to respond to my emails almost instantly. Thank you very much Doede.
From then on it was very easy. I soldered the resistors and hooked up the output transformers. A glorious sound! It is too early to talk about the differences between capacitor loaded and transformer loaded 1794 outputs because that takes an extensive period of serious listening. I am in the middle of that now.
Dear Doede, You have not only designed a superb diy DAC, which is easy to assemble and versatile enough to be used with vaious power supplies and most of all extremely good sounding, but you take the time to help out your customers when they need help. And... RTFM!
Designer, manufacturer and help-desk, all in one person! Thank you!
Kind regards
Henry
Thanks for the feedback and flowers 💐 Henry ! I ALWAYS (want to) make sure every DDDAc works as expected and so far it always worked out nicely.
Nice you said it way, design manufacturer and support all in one. Well it makes diagnose and support easier of course 😀
ENJOY THE DDDAC,
Doede
Nice you said it way, design manufacturer and support all in one. Well it makes diagnose and support easier of course 😀
ENJOY THE DDDAC,
Doede
Further to this, if we put two lifePO4mini in series 5v + 3.3v to give 8.3v, which may drop a bit lower. Is 8.3v sufficient, for is 9v the min?
well, the drop out depends a bit on temperature and current (see datasheet) and 8.3 would be very hard at the limit. 8.4 to 8.5 Volt would be better
Hi Stretchneck,
I do not know if this will work. In the 'big' LifePO4 the batteries can be connected in parallel by installing jumpers, but afaik they are charged individually. Better ask Ian Canada about paralleling individual LifPO4Mini outputs. He responds to emails promptly.
The DDDAC designer Doede Douma helped me enormously with the use of the 'big' LifePO4 for the new DDDAC.
I use LifePO4 with one 3.3V battery connected to the digital voltage OUTPUT of DDDAC. This works flawlessly. The other LifePO4 output uses three 3.3V batteries in series and is connected to the 9V analogue INPUT. This works fine as well. I've monitored the voltage over an extended period of time and could not find any problems, either with current consumption or heat build-up.
I have not tried Doede's suggestion in post #88 to connect a 3,3 LifePO4 battery to the 4V input of DDDAC. For this the charging voltage of LifePO4 is presumably too low. Mine is set for 3.38V. Since everything is working fine with 3.3V to the digital voltgae OUTPUT, I have no desire to start experimenting again.
I hope this will help.
By the way, what do you think of the new DDDAC as far as sound qualtiy is concerned?
Kind regards,
Henry