DAC gallery

Nice work, can you detail all the boards used?

Sure,
It starts with an RPI, with Ian's little U.FL adapter on it, 3 coax goes to Ian's I2S FIFO than I2StoPCM board. Those are stacked on each other. Than my little DAC board comes, that is version x of my AD1865 boards. I found LM431 power supplies on board to be a good solution. I have 2 of them on the board, for the analog +- and the digit +.
The DAC runs in current mode, the termination resistors are not visible, under interstage the transformers on the analog board. The analog board is not a PCBA, it is just a cnc cut board, the traces are wires. The analog amplification has tube rectification and AN copper foil caps on output. In the middle, there is the tube filament power supply board with additional RC filtering. The toroid feeds that and the tub rectifier of the analog amplifier.
There are 2 more power supply boards, one has a dual output about 9V and a single 9V for the DAC board analog and digit board (not 5, because there is regulation on the DAC board). Last, between the toroid and the DAC PSU on the right, there is a 5V supply for the PI and the digital line boards.
I need to replace the toroid.
Than I will replace the DAC board to analog board and the analog board to cinch connector analog cables to AN KSL cables.
And the tubes too. At the moment I have old used tubes from my drawer, I will get some new tubes into it.

Regards,
JG
 
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PCM2707 + PCM1793 + OPA2134 for post-DAC filter + LMH6643 power op amp for headphone output.

Negative rail is provided by LM2662MX (modern more powerful version of ICL7660) switched-capacitor converter. Both negative and positive voltages are filtered via damped (Q about 1) LC filters.

Full project data: https://github.com/e-asphyx/usb_dac
 

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My TDA1541 dual dac pcb

This is my first attempt at a dac pcb. Its for use with Iancanada's I2S to pcm board shown next to it.
The dacs will be operating in simultaneous mode with true and inverted data, one dac per channel.

I will be testing it using 100r I/V resistors and a pair of Sowter bifilar wound i/v transformers.
Future plan is for an I/V pcb with four AD844 and four opamp buffer/drivers for the transformers, probably OPA627 or similar.
 

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This is my valve DAC: DIX4192 SPDIF interface, Spartan 6 FPGA module and SRC4392 for the digital signal processing, three times E88CC per channel as the actual DAC, 85A2 voltage reference, ECC81 crystal oscillator, two EF80 clock buffers, potcores and polystyrene capacitors as reconstruction filter. See https://linearaudio.net/articles?title=The+valve+DAC and https://linearaudio.net/downloads for details. By the way, I replaced the large transformer with two 50 VA toroids.
 

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Nice. How does it sound?

The first time I seriously listened to it, early September last year, I played a CD with Vivaldi's Nisit Dominus performed by Le Banquet Celeste. The output of the DAC was connected to a Technics SU-V40 amplifier (solid state) which drove a pair of Sennheiser HD-215 headphones.

I was really impressed by how beautiful it sounded. It was almost as beautiful as during their concert at the old music festival in Utrecht in August 2016.

In my opinion this mainly shows that I'm a fan of Le Banquet Celeste. I can't possibly say if I would have been any less impressed if someone would have secretly replaced the DAC with any other well-designed and level-matched DAC.
 
The first time I seriously listened to it, early September last year, I played a CD with Vivaldi's Nisit Dominus performed by Le Banquet Celeste. The output of the DAC was connected to a Technics SU-V40 amplifier (solid state) which drove a pair of Sennheiser HD-215 headphones.

I was really impressed by how beautiful it sounded. It was almost as beautiful as during their concert at the old music festival in Utrecht in August 2016.

In my opinion this mainly shows that I'm a fan of Le Banquet Celeste. I can't possibly say if I would have been any less impressed if someone would have secretly replaced the DAC with any other well-designed and level-matched DAC.

Thanks for the recommendation for Le Banquet Celeste. I has a quick listen on Youtube
https://www.youtube.com/watch?v=16j5BvJX0VE
https://www.youtube.com/watch?v=Djq4NJXZo5M
and was impressed.

Your DIY DSD valve DAC must be fine with it sounding so close to the live concert. I wonder how hard the build is?
 
Thanks for the recommendation for Le Banquet Celeste. I has a quick listen on Youtube
https://www.youtube.com/watch?v=16j5BvJX0VE
https://www.youtube.com/watch?v=Djq4NJXZo5M
and was impressed.

Your DIY DSD valve DAC must be fine with it sounding so close to the live concert. I wonder how hard the build is?

It took me about three and a half years to design, build, debug and improve it, but making a second one would of course be much less work. The FPGA configuration files and PCB layouts including all the latest improvements are available on the Linear Audio website, so have a look if you are interested. You need to solder some fine-pitched SMD components, although I've used relatively large SMDs wherever possible.

By the way, it is not really a DSD DAC, although it does support DoP. Basically anything that comes in is converted to 200 kHz sample rate PCM, interpolated to 3 MHz PCM and then converted into a 27 MHz single-bit signal. You can choose between three algorithms for the conversion to single bit; in the mode that works best, this last conversion involves a special kind of pulse width modulator embedded in a sigma-delta modulator loop. The advantage of this is that the loop can be properly dithered, which prevents all the idle tone problems you would otherwise have with a sigma-delta.