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

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G

gumisb

Member
Joined 2020
soekris said:
Actually the si570 datasheet also said this very important:

"the device allows reprogramming
of the DCO frequency up to ±3500 ppm from the center
frequency configuration without interruption to the
output clock."

Meaning no glitches with 3500 ppm change, the number for the si514 is no glitches with 1000 ppm change.... That what I use for my tracking, one reason I want to stick with the SiLabs parts....

But I am planning to work on my PLL, but don't expect new dam1021 firmware soon, it will come first for the dac2541, that use the Si570, and then backported to older products.
What I'm thinking about now is to extend the initial measurement of the incoming clock, before switching to the slow PLL, and then do fewer updates at higher resolution. Right now I first measure the incoming clock at 100 mS, open up for audio output, and then again measure over 1 sec and adjust. The goal was to have very shot interruptions between sample rate changes.

Remember that a lot of design decision was taken over 6 years ago....

And I will not add multiple modes, the preferred way is that it just work for any signal, adding a switch is stupid, in my opinion.
Click to expand...

Any progress?
 
R

Ronnhedh

Member
Joined 2007
Portable Dac

The long in-work of aportable Dac part of a music system is ready.
It took such a long time is due to the Chinese showing their worst side by sending two broken bluetooth receivers. But the third time, a working unit came. I2S bus is connected and it worked immediately. With an old-fashioned antenna, both range and sound quality are better.

Well, it's been a lot of handicraft anyway. All connector are homemade as the space is not enough for something ready.
Without carbon fiber profiles, it would hardly have been possible to craft a light, attractive and strong casing. Only glue and double-sided adhesive tape is used. There is not a screw.

The dam1121 is Soekris' smallest size Dac and so nicely built that it deserves to be shown under the mobile glass.

The battery with a Traco low-ripple converter supplies +-5V and lasts for 6 hours of use. The UDB connector allows for recharging ad well as an I2S temote connector.

The companions are a switched ELS amp with earspeakers from Stax.


Sounds super.
As you realise, I am betting on a pandemic-free near future.

Lars
 

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A

atohmdiy

Member
Joined 2019
Ronnhedh said:
The long in-work of aportable Dac part of a music system is ready.
It took such a long time is due to the Chinese showing their worst side by sending two broken bluetooth receivers. But the third time, a working unit came. I2S bus is connected and it worked immediately. With an old-fashioned antenna, both range and sound quality are better.

Well, it's been a lot of handicraft anyway. All connector are homemade as the space is not enough for something ready.
Without carbon fiber profiles, it would hardly have been possible to craft a light, attractive and strong casing. Only glue and double-sided adhesive tape is used. There is not a screw.

The dam1121 is Soekris' smallest size Dac and so nicely built that it deserves to be shown under the mobile glass.

The battery with a Traco low-ripple converter supplies +-5V and lasts for 6 hours of use. The UDB connector allows for recharging ad well as an I2S temote connector.

The companions are a switched ELS amp with earspeakers from Stax.


Sounds super.
As you realise, I am betting on a pandemic-free near future.

Lars
Click to expand...

Funny i am working on something similar, except i won't use a battery, but i will include a player. I will also use a dam1121, and different other parts :
headphone amp base on opa1678 + opa1656
silent switcher psu
nano pi neo 3 as mpd player
probably a couple of amb a24 as buffer and se-bal converter
All that in a takashi MXB4-10-14, i receive the case today.

For the software part the nano pi is suppose to support 24/192 in it's i2s out. I will use mpd and the api you can find on the net to control the hardware mixer of the dam.

I should finish it in a couple of weeks, i will post some photos.
 
P

PavZ

Member
Joined 2021
Muting mod

soekris said:
Muting jfets to gnd. jfets are normally on, so about 30 ohms shorting....
Click to expand...
I apologize for possible offtopic but is it the same way - jfets are shorting outputs instead of cutting a signal line - in dac1421 and dac1221? What about headphones output in dac1421 that also has jfets? The shorting obviously makes muting jfets removal mod not needed because they can't spoil audio quality.
 
P

PavZ

Member
Joined 2021
living sounds said:
Easier, yes, but I would prefer it to be closer to the regulator and the clock, also as close as possible to the cap already there to minimize resonances.
Click to expand...
At least in some versions of dam1021 it is also possible to solder the extra capacitor directly to the 3.3V regulator because/if the tab is Vout and the left pin is ground. I've seen this idea on some Asian site. This way parasitic inductance of traces+leads between the big capacitor and the regulator should be the smallest possible. I tried to simulate some models and this seems to be somewhat improving the result.
 
T

tiggerkater55

Member
Joined 2015
hi everybody,
I hope its ok to post my question in this thread, but i think you have quite some experience with this topic:
I want to power my dam1021 board with salas ultra bibs, I recently finished. Now i have two r-core transformers: 2x15V or 2x12V. which one would you prefer? or in other words: is it better to power the dac with 9/10V or around 12V?
thanks a lot!
 
L

living sounds

Member
Joined 2008
soekris said:
Actually the si570 datasheet also said this very important:

"the device allows reprogramming
of the DCO frequency up to ±3500 ppm from the center
frequency configuration without interruption to the
output clock."

Meaning no glitches with 3500 ppm change, the number for the si514 is no glitches with 1000 ppm change.... That what I use for my tracking, one reason I want to stick with the SiLabs parts....

But I am planning to work on my PLL, but don't expect new dam1021 firmware soon, it will come first for the dac2541, that use the Si570, and then backported to older products.
What I'm thinking about now is to extend the initial measurement of the incoming clock, before switching to the slow PLL, and then do fewer updates at higher resolution. Right now I first measure the incoming clock at 100 mS, open up for audio output, and then again measure over 1 sec and adjust. The goal was to have very shot interruptions between sample rate changes.

Remember that a lot of design decision was taken over 6 years ago....

And I will not add multiple modes, the preferred way is that it just work for any signal, adding a switch is stupid, in my opinion.
Click to expand...


Dear Soeren,

could you please give us an estimation when we can expect the firmware update?

Thanks!
 
L

living sounds

Member
Joined 2008
Peterma said:
I would imagine its not a good business model to make the low to middle products compete with the flagship model in the product lineup.
Click to expand...

I don't really know what you are talking about. But I don't consider it good business practice not to quickly move to fix an obvious flaw in a product. And yes, part of the frequency spectrum (11025 Hz) jumping around 3dB in amplitude due to massive clock drift is an actual flaw.
 
TNT

TNT

Member
Joined 2003
Paid Member
I don't think Sören thinks there is any performance differences but rather that they are all equal but with different features sets. But the man is somewhat of an enigma so who knows really? :)

The question above is about when a promise will fall out. Last time, with the 4k support in the 1121, it took a few years and some bad weather ;-)

//
 
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