• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

* You can now select four sets of filters, named Linear, Mixed, Minimum and Soft.

[...]

To experiments with filters, the filter .txt file and updated mkrom utility is here, note that FIR1 coefficients now have to be < 1, but are now checked by mkrom utility.

http://www.soekris.dk/1021filt_099.txt
http://www.soekris.dk/mkrom.exe

Do I understand correctly that old and new filters can coexist? It seems different type values have been assigned to them. How user can change between the old one and the new set?
 
Thanks for the Firmware update Soren. I still get 'clicks' with track changes, but can hear tracks from the start. It would be nice to get rid of the 'clicks' .

The source could be the USB interface or the Player. To help improve, anybody with clicks please let me know:

Is it just between tracks with different sample rates or between all tracks ?
What USB interface are you using ? Or what interface if not USB ?
What Player software are you using ?
How powerful / long is the click ?
Improved from previous version ?
 
Clicks still persist for me as well.

However they only happen when input sample rate is different, changing tracks with the same sample rate doesn't trigger re-locking. The length of the click hasn't changed and I believe that the amplitude changes depending on what signal is being played.

Clicks were detected using Foobar when switching between 16/44 and 24/96 content.

Using Amanero interface, last revision.
 
Last edited:
Forgot to mention:

FIR2 filter can also be selected, types are 8..11 and as possible will track FIR1 selection.

There is new uManager command "filters [all]", will show either current selected filters or all possible.

The uC operates in two modes:

Management mode, entered though +++, for download and setting parameters, this mode is not really supposed to be used while paying audio, it can not change things and pll will not track. Exit command will return to playing mode.

Playing mode, normal mode while playing audio, short commands and status over the serial port work, command have to be upper case:

Ix, x = 0..3, select input
Vx, x = -80 to +10, set current volume
Fx, x = 4..7, select FIR1/FIR2 filter, with immediate effect

In playing mode it will also output the short status to the serial port:

Rx.xx, Current uC Firmware Revision, at power up only
Lxxx, PLL lock at speed xxx

Will update website and release full manual with all info shortly.
 
Last edited:
Thank you for the update Soren. I still have the clicks. Hope the following helps.

Is it just between tracks with different sample rates or between all tracks ?

Between tracks with different sample rates.

What USB interface are you using ? Or what interface if not USB ?

Amanero

What Player software are you using ?

Vox for Mac (VOX Player for Mac - play FLAC, MP3, APE, 24/192 on your Mac OS X)

How powerful / long is the click ?

Quite powerful, not very long, shorter than pronouncing "click". Testing with "Mixed" filter.

Improved from previous version ?

No.

Is there anybody with Amanero who doesn't get clicks?
 
Playing mode, normal mode while playing audio, short commands and status over the serial port work, command have to be upper case:

Ix, x = 0..3, select input
Vx, x = -80 to +10, set current volume
Fx, x = 4..7, select FIR1/FIR2 filter, with immediate effect

In playing mode it will also output the short status to the serial port:

Rx.xx, Current uC Firmware Revision, at power up only
Lxxx, PLL lock at speed xxx

Will update website and release full manual with all info shortly.

It would be extremely useful to have query commands that a controller can use to obtain the current DAM status on demand. For example:
V? - output current volume
I? - output current input
An so on for the other commands.

Regarding the clicking problem.
It is better, but not completely solved. I will post my findings when I have time to do proper testing.
Would it be possible to implement a MUTE control output that DAM activates when there is no signal lock? It would allow muting the outputs externally to solve the problem once and for all.
If possible, perhaps the PWRLED pin could be reassigned to MUTE control? For dac builders it would also work quite well as a visual LED indicator for signal lock.
 
Been playing some. Yes still clicks when changing songs. Even doing "fast forward" in songs. I am not sure if it is mpd (music player deamon" that looses track or something.
I can see from the umanager in "play" mode that it loads a filter during evry song change (regardless of sample rate, even if it is the same) and loads filter when doing "fast forward" for instance. It is this filter loading that causes the "click".
Sometimes the click is low in volume. Sometimes quite loud.

But maybe its just me. I think the dac has good sound with the latest fw? (and filters)
dam1021 uManager Rev 0.99 20150814 FPGA Rev 0.99 Press ? for help.

# exit

L044
L044
L044
L044
L044
L044

This is when changing songs and doing "rewind or fast forward" in songs.
 
Last edited:
It would be extremely useful to have query commands that a controller can use to obtain the current DAM status on demand. For example:
V? - output current volume
I? - output current input
An so on for the other commands.

Regarding the clicking problem.
It is better, but not completely solved. I will post my findings when I have time to do proper testing.
Would it be possible to implement a MUTE control output that DAM activates when there is no signal lock? It would allow muting the outputs externally to solve the problem once and for all.
If possible, perhaps the PWRLED pin could be reassigned to MUTE control? For dac builders it would also work quite well as a visual LED indicator for signal lock.

One observation with the new firmware is that the PWRLED pin is no longer inverted to what the onboard LED state is. This completely breaks my output muting/shunter due to it expecting the original inverted signal. Not a big deal as it actually simplifies the circuit quite a lot, just have to redo it. Now that I have to rip it apart I should be able to post a schematic if anyone wants to implement their own hardware mute.

EDIT: Yes the pops are bad now that I have to hear them again, yes its wife-waking material, suddenly remember why I went through the trouble to do hardware muting.
 
Last edited: