DAC AD1862: Almost THT, I2S input, NOS, R-2R

Member
Joined 2018
Paid Member
Interested to build this....I have chips from the Rochester GB and a PCB on its way.

I built a couple Ian Canada dacs . My brother uses one in his expensive commercial system. He is a vinyl man. Years with a maxed out Linn LP12 and now he has a Brinkman Bardo and some nice electronics ...mega system.
He really rates the Ian ESS streamer and it obviously takes the strain from an expensive stylus wearing out. But he finds it more than acceptable and even comparable to his his LPs.

Would be interesting to see how the AD dac compares.i guess neither of us have heard a good old dac implemented well.
 
Sadly no Mouser package today so the DAC puzzle will have to wait until next week. I did receive the PCBs for my I/V stage though.

lYtq8YA.jpg
 
QUOTE=miro1360;6468613]@nano35
Try to slow down DATA with 1k resistor (in series), if not helped install the resistor on the BCK (either one or the other).

Thanks I will try that.
I will take a look of my usb interface.

Diyiggy,
I also tried the dac directly connected to Fifopi’s I2S.
It still cannot do beyond 96KHz.[/QUOTE]


nano I just received i2soverusb and have connected everything and it is playing over raspberry usb, below is a screen shot from ROON. i2soverusb was automatically detected like this... I think you are having some sort of hardware problem or something not connected right if you haven't been able to solve your problem by now.


P.S.
It is jaw dropping change from hifiberry I2S out...



i2soverusb.png
 
Last edited:
Here is a simplified simulation (without 32b buffer) of the shift register for someone who would be worried about some lost MSB bits. The simulation proves that the shift register is universal and all MSB bits are played for either 16b (aligned correctly) or 24b recordings and only 4 LSB bits from 24b are discarted (or not shifted in) :magnify:
 

Attachments

  • I2S-shift-register.jpg
    I2S-shift-register.jpg
    481.7 KB · Views: 564
  • I2S-shift-register-simulation-16B-20B.jpg
    I2S-shift-register-simulation-16B-20B.jpg
    411.3 KB · Views: 568
  • ad1862-data.jpg
    ad1862-data.jpg
    225.7 KB · Views: 568
Last edited:
The function of output filter is to cut out a potential interference above the audible band. The side effect of such a filter is that it also modifies the audible sound. Here comes the question of whether or not to use it and which one, because there are many types (bessel, sallen-key, butterworth, chebyshev, elliptic, custom, passive ...) and each type has different sound colorization or distortion :D
To make a transparent active or passive filter is tricky and really really a long way.
The current output of DAC, or voltage output from I/V can be used for an experimental PCB with filters ... the question is whether or not the time effort brings a real audible benefit :)
 
Last edited:
Issue of not going beyond 24/192:

I tested on RPI4+moode version 7 (no Fifopi); it works at 24/192KHz!
I cannot leave the SoX resampling to "any" as my 24/384 files won't play well.

Back to RPI3B+moode version 3.84(with Fifopi as usual);
somehow it plays fine at 24/192KHz!
I don't know why it did not play at 24/192 before.
My collection consists of 16/44.1, 24/96 & 24/384.
Happy listening.

I also tested with "1KΩ resistor" in series with DATA and / or CLK(replacing 22Ω resistors); none worked-no sound.

now, what about muting circuitry? I have bad habbit of manually switching songs and there are "2 big pops" in between. It is no big deal if I let it play in order by itself.
I think I am asking too much, an't I? : )
 
... now, what about muting circuitry? I have bad habbit of manually switching songs and there are "2 big pops" in between. ...

These pops seems be popular in RPI. This is definitely not happening in windows (with xmos USB or PCM2706).
Seems to me like a configuration issue or a driver issue in linux or rpi. The question is how to solve it :confused:

Click/Pop/Crack when changing tracks : Raspberry Pi • RuneAudio Forum
Moode Audio Player for Raspberry Pi
audio - DAC pops on Song Start/Stop in Raspbian - Stack Overflow
bcm2835 ALSA sound: pop on sound playback start/completion * Issue #128 * raspberrypi/linux * GitHub
PI 4 USB audio clicks/pops - Raspberry Pi Forums
My solution to pops and clicks : Raspberry Pi • RuneAudio Forum
https://community.volumio.org/t/pop-between-tracks/5313/3
 
Last edited: