Hi nedi,
Two Mosaic II DAC prototypes are up and running (breadboard version, PCBs mounted on a piece of wood, modifications on all PCBs).
There have been major hardware and software modifications that have taken much more time than expected.
The final prototype PCBs have just been completed.
Next up is designing and manufacturing a prototype housing and check if everything fits and works as planned.
Two Mosaic II DAC prototypes are up and running (breadboard version, PCBs mounted on a piece of wood, modifications on all PCBs).
There have been major hardware and software modifications that have taken much more time than expected.
The final prototype PCBs have just been completed.
Next up is designing and manufacturing a prototype housing and check if everything fits and works as planned.
Oh! dear, here we go again...
While you are at that, have you revisited the "thermal memory effect" recently???
There have been several threads of this (putative) effect, concerning power amplifiers, and I myself initiated my experiments with astonishing success, even with my limited skills and means...perhaps you might take a look in case you have some discrete circuits in there...
Memory Distortion Philosophies
The AMNESIS amp: a good amplifier, like a gentleman, has no memory.
Best wishes,
M.
PS: forgive the many errors in the schematics...there were initial thoughts only...
Hi John,
Good news, thank you for information
Yes, the best digital-to-ANALOG converter is going to be improved!
Dear John,
Are you aware of the MQA process?
MQA Playback | Bob Talks
Do you think the Mosaic is compatible with it?
Apparently, we could achieve Master reproduction...
Cheers,
M.
Are you aware of the MQA process?
MQA Playback | Bob Talks
Do you think the Mosaic is compatible with it?
Apparently, we could achieve Master reproduction...
Cheers,
M.
I've not tried it with TDA1541, only with TDA1387 but Toshiba SSM3J327R is about the highest transconductance P-channel FET I've found and works great. High transconductance (gm) is required to present the lowest impedance to the DAC.
Matt Garman is also trying out this FET on his RPi 'HAT' I believe which also is using TDA1387s.
If TDA1541 prefers an N-channel FET then I'd go for SSM3K339R.
For what its worth, I have been using Uptone's little uspcb adapter to plug directly my SBC into the DAC. It has shielded power and data lines. I tried building my own cable, but my soldering skills are terrible, so this seemed like a good alternative at a reasonable cost.
Have a look at this thread, I think I posted a schematic or two and an LTSpice file : Impressions: USB DAC: TDA1387 NOS vs PCM5102A Delta-Sigma
Hi,
Vout depends on number of paralelled DAC chips and I/V R chosen.
In my case, 8 chips per channel and 131R from memory gives +/- 2,5Vpp, which sounds a little lower than average DVD player but still has plenty of output to drive conventional amps into party levels. You can increase I/V R or number of chips- Eight just sounds so good...I will try with 16 as time allows...
BTW, I finally had the time and energy to mount my Raspberry Pi system, and after many many attempts (I don't have an expert brother...) I finally succeeded with Kodi through Libreelec, which recognizes Mosaic DAC without problems and sounds impressively transparent. I am trying to figure out this hermetic player for optimal settings...
For example, it says: "max sampling allowed" or something like that, which makes one wonder is it upsampling? is it keeping the default sampling from the file? The yellow light is stuck at the rightmost led...
Oh, and BTW, I run a minimalist system with only an external HD connected and lots of ERS sheets...now I have to configure the remote control and some TV channels
What made it difficult is the fact that whenever I copied the Mosaic UV.img file to the SD card, the OS would not start normally, the Raspbian GUI wouldn't open...
Now to enjoy the Best DAC Ever.
Cheers,
M.
PS: I will test my DIY USB cable with power and signal separated.
Vout depends on number of paralelled DAC chips and I/V R chosen.
In my case, 8 chips per channel and 131R from memory gives +/- 2,5Vpp, which sounds a little lower than average DVD player but still has plenty of output to drive conventional amps into party levels. You can increase I/V R or number of chips- Eight just sounds so good...I will try with 16 as time allows...
BTW, I finally had the time and energy to mount my Raspberry Pi system, and after many many attempts (I don't have an expert brother...
) I finally succeeded with Kodi through Libreelec, which recognizes Mosaic DAC without problems and sounds impressively transparent. I am trying to figure out this hermetic player for optimal settings... For example, it says: "max sampling allowed" or something like that, which makes one wonder is it upsampling? is it keeping the default sampling from the file? The yellow light is stuck at the rightmost led...
Oh, and BTW, I run a minimalist system with only an external HD connected and lots of ERS sheets...now I have to configure the remote control and some TV channels
What made it difficult is the fact that whenever I copied the Mosaic UV.img file to the SD card, the OS would not start normally, the Raspbian GUI wouldn't open...
Now to enjoy the Best DAC Ever.
Cheers,
M.
PS: I will test my DIY USB cable with power and signal separated.
What made it difficult is the fact that whenever I copied the Mosaic UV.img file to the SD card, the OS would not start normally, the Raspbian GUI wouldn't open...
Strange Max that the Mosaic image didn‘t work for you - I used it even with non-Mosaic DAC and it works like a charme. I must say though that I use exactly the setup as described by John and Gordon on the website, with minimServer etc., with excellent results.
Hi John,
just a curiosity about ternary logic switches, are you using discrete devices or logic IC (flip-flop, latch) like Soekris or Rockna's devices?
I'm also working on a discrete DAC (DIY design, not a commercial device) and I have approached in the same way using ternary swithces to switch between positive, ground and negative.
I have not yet decided which is the best way, there are advantages and disadvantages in both cases. With discrete parts you can reach very low RDS-on (20-30 mOhm or so), but they are slower that logic ICs. Also the logic to drive discrete switches is more complex and p-channel devices are tipically different from n-channel devices (RDS-on, input and output capacitance, speed).
Conversely logic ICs are simpler to drive, are faster but have greater RDS-on (10 to 20 ohm or so), that finally affects the ladder network precision (monotonicity).
Andrea
just a curiosity about ternary logic switches, are you using discrete devices or logic IC (flip-flop, latch) like Soekris or Rockna's devices?
I'm also working on a discrete DAC (DIY design, not a commercial device) and I have approached in the same way using ternary swithces to switch between positive, ground and negative.
I have not yet decided which is the best way, there are advantages and disadvantages in both cases. With discrete parts you can reach very low RDS-on (20-30 mOhm or so), but they are slower that logic ICs. Also the logic to drive discrete switches is more complex and p-channel devices are tipically different from n-channel devices (RDS-on, input and output capacitance, speed).
Conversely logic ICs are simpler to drive, are faster but have greater RDS-on (10 to 20 ohm or so), that finally affects the ladder network precision (monotonicity).
Andrea