• The Vendor's Bazaar forum is for commercial offers and transactions. Only unmoderated members can post here.

    diyAudio provides this forum 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

Jump to Latest
#1,002
Dimdim said:
Hi guys,

Here is a teaser:

attachment.php


attachment.php
Click to expand...

I'm teased 🙂
 
#1,009
soekris said:
*
****************** NOW TAKING ORDERS ********************

I have been working on a little side project, now it's time to present it for everybody here....

It's a DAC module based on a discrete R-2R sign magnitude DAC design, with FPGA based reclocking and custom digital filters, < 1 ps jitter clock generator, with 28 bit resolution so there is headroom, oversampling up to maybe 3.072 Mhz. Up to 24 bit / 384 Khz input from SPDIF, I2S and USB (via USB to I2S interface board), with isolation on the I2S interface. The board will be very flexible, with digital volume control and filter parameters that can be downloaded, a possibility is also to add digital crossover filters, but that will probably not be ready for first production lots, although the board is firmware upgradable over a simple serial connection.

The basis R-2R network has an output voltage of 1.4V RMS and output impedance of 625 ohm and can therefore drive a lot of things directly.... There is also onboard balanced output drivers that can drive high impedance (>= 300 ohm) headphones directly. The power supply is also onboard, just add a 5W toroid transformer.

It is a small mostly surface mount PCB, and yes, I have working prototypes, see below.... But it's not really something for home assembly, with the FPGA in BGA package and 600 pcs SMT parts.... So yes, if there is enough interest it will go into real production, with sales though two existing online shops in US and EU.

Performance of first prototypes using 0.05% resistors is better than expected, see 1 Khz -1 db and -60 db FFT plots. I believe that the sound quality will be the absolute best, better than any Delta Sigma DAC, in class with discrete DAC's from totaldac and msb technology. And for way way less cost 🙂
Click to expand...


An exciting project. I wonder, for a relative newbie, how would you compare the performance specs to, say, Theta Digital's Generation VIII S3 DAC?
 
#1,010
TNT said:
Thanks - looks interesting. How does one manipulate this settings?

//

Aha its not a setting but a control out pin.... Sören, can this be exploited somehow?
Click to expand...

In principle any source should output zeroes when it don't have valid audio, if you need a "mute" pin then the source (read amanero) have a problem....

On the other hand the R-2R DAC shouldn't output anything without valid input data.... I'm currently muting by uC firmware, but that only check the input every 100 mS. There are supposed to be real time muting in the FPGA, but I had trouble with it, and as I otherwise didn't experience any problems with my setup (using a DIYINHK usb interface), I decided to complete that part later....

There is no direct mute input to the R-2R DAC, I just need to work on completing the FPGA mute circuit...
 
#1,011
it would be nice to finally have some sound impressions comparative to other well known DACs and their implementations such as the TDA1541, PCM1702, CS4398, ES9023, ES9018, pcm5102, etc. ; I would be curios about a particular sound signature of this R2-R DAC compared to these other DACS from those who own or have listened to some of them 🙂
 
#1,015
alecm said:
Soekris,
please find out what is going on with my order. I have paid Wednesday. But till now i haven't any reaction on my order and numerous letters to you and company. Thank you in advance.
Click to expand...

Speaking for Soekris, he doesn't handle the actual orders, he has someone who takes care of that part of the business.

And many people put in their orders ahead of you, so I imagine you need to relax a little, and wait. 🙂
If you were not in the first group (I put my interest in last summer BTW), then you will have to wait for the 2nd batch of boards, 1st batch is sold out. This info is in the first post.

Randy
 
#1,017
But till now i haven't any reaction on my order and numerous letters to you and company.
Click to expand...

Sadly I have seen this over and over on Diyaudio when a new offer came out... people being all over the place and complaining, writing numerous(!) letters but not being able to just read a few pages of the thread and finding the important bits. It's not like you are shopping at Amazon, Mr.!
 
#1,018
soekris said:
In principle any source should output zeroes when it don't have valid audio, if you need a "mute" pin then the source (read amanero) have a problem....

On the other hand the R-2R DAC shouldn't output anything without valid input data.... I'm currently muting by uC firmware, but that only check the input every 100 mS. There are supposed to be real time muting in the FPGA, but I had trouble with it, and as I otherwise didn't experience any problems with my setup (using a DIYINHK usb interface), I decided to complete that part later....

There is no direct mute input to the R-2R DAC, I just need to work on completing the FPGA mute circuit...
Click to expand...

Okidoki. Just so you know - volume setting has no impact on blog level.

//
 
#1,019
TNT said:
If you look at the drawing Sören provided of the board, there is a box surrounding the inputs/outputs that is "isolated". None of these are used for galvanic or opto s/pdif.

- Galvanic s/pdif (shoild) use a transformer which is passive alas, no power needed.
- Opto requires a receiver module which is active and needs power - however as the glassfibre cable isolates the dad for outside, no isolation on-board is needed and this, the device can be seen to belong to the core DAC itself (the isolated part) so power should be taken from S2 but from pins outside the ISO box as these provide power (the ISO power must be fed power)

I only have USB possibilities.
//
Click to expand...

Let me correct som spelling erros in this post. Forgive me my sloppy writing. It is affiliated with my weakening eyesight 🙁

If you look at the drawing Sören provided of the board, there is a box surrounding the inputs/outputs that is "isolated". None of these are used for galvanic or opto s/pdif.

- Galvanic s/pdif (shoild) use a transformer which is passive alas, no power needed.
- Opto requires a receiver module which is active and needs power - however as the glassfibre cable isolates the DAC from outside, no isolation on-board is needed and thus, the device can be seen to belong to the core DAC itself (the isolated part) so power should NOT be taken from S2 but from pins outside the ISO box pins as these provide power whereas the ISO power pins must be fed power)
 
#1,020
Thanks mate - as it's the 'Monday' referred to in #885 (I think), was curious where board arrived in the US, and are still scheduled to start shipping today.

Not riled up mind you, just curious.

I have transformers inbound, along with the parts needed to complete the power supplies. Really looking forward to checking it out.

ristar said:
This is his update with regard to those who ordered from the US store:

Post #885
Click to expand...
 
Last edited:
You must log in or register to reply here.
Top Bottom