Signalyst DSC1

[Frank513]

oK Nautibuoy

The first thing I will do is try to derive a schematic from the PCB, particularly the output stage around the transformers.

I didn't understand, please tell me what do you plan to do?

The transformers are the I/V stage (and perhaps gain as well)?

If i tell right, dsc1 is R/2nR dac.
So there is negative voltage in outputs of shift register.
AD844 sums all bits and inverts voltage.

Is I/V transformer usable here?
Is there rather need V/V transformer?

 

[nautibuoy]

I didn't understand, please tell me what do you plan to do?

I plan to understand the understand the changes that have been made to the original circuit first. No plans beyond that at the moment, other than to finish the assembly of my DSC1.

 

[Frank513]

I plan to understand the understand the changes that have been made to the original circuit first. No plans beyond that at the moment, other than to finish the assembly of my DSC1.

i understand you plan to understand the understand the changes.

If i tell right, dsc1 is R/2nR dac.
So there is negative voltage in outputs of shift register.
AD844 sums all bits and inverts voltage.

After some thinking it should have current in input of AD844.
So I/V transformer is the good one.

 

[Terry Demol]

I obviously can't speak for Jussi but he is on record as having no interest in producing hardware and he placed his original DSC1 under the CERN Open Hardware Agreement

Signalyst

which says "anyone should be able to see the source (the design documentation in case of hardware), study it, modify it and share it."

CERN Open Hardware Licence - Cernohl - Open Hardware Repository

The Chinese kit producer seems to credit Jussi through reference to his original schematics and recommendation to use HQPlayer. Where they're not playing ball is by failing to respect the CERN licence terms with respect to sharing they're modifications; they should be distributing their updated schematics and, I believe, board layouts.

Ray

Yes, agreed on all counts.

Terry

 

[nautibuoy]

i understand you plan to understand the understand the changes.

I also plan to type more carefully and to proof what I type....

 

[Frank513]

Some news i share to vulgarize the functioning of DSC1 DAC.

Here three main step of dsc1:

An externally hosted image should be here but it was not working when we last tested it.

Digital signal coming from HQ player is transformed in analog signal thanx to 74AHCT595. The sum is done by AD844 ( in addition to isolate).


The analog curve is smoothed by fourth order low pass filter.

An externally hosted image should be here but it was not working when we last tested it.

Both Sallen Key 2nd order low pass filter have a gain=1.


To finish with the last step of dac:

An externally hosted image should be here but it was not working when we last tested it.

I do not understand reason of this op amp.
If R806 was installed, it could be a non inverting amplifier...
Someone has an idea about it?

 

[nautibuoy]

I do not understand reason of this op amp.

See post #43

http://www.diyaudio.com/forums/digital-line-level/254935-signalyst-dsc1-5.html#post4164115

Your diagrams are very small and difficult to read.

 

[Frank513]

I should be more visible.

Some news i share to vulgarize the functioning of DSC1 DAC.

Here three main step of dsc1:

Digital signal coming from HQ player is transformed in analog signal thanx to 74AHCT595. The sum is done by AD844 ( in addition to isolate).


The analog curve is smoothed by fourth order low pass filter.

Both Sallen Key 2nd order low pass filter have a gain=1.


To finish with the last step of dac:

I do not understand reason of this op amp.
If R806 was installed, it could be a non inverting amplifier...
Someone has an idea about it?

 

[Frank513]

Nautibuoy,
what is your opinion (sound quality) about Aikido lin stage?

 

[benkit]

Hello,
Please advise where I can find kit of PSU for DSC1 DAC.

Thank you
BK

 

[nautibuoy]

Hello,
Please advise where I can find kit of PSU for DSC1 DAC.

Thank you
BK

I've not seen a kit for a DSC1 power supply but one isn't essential as you can easily use other good quality power supply modules and maybe even improve on the published Signalyst design.

 

[nautibuoy]

Nautibuoy,
what is your opinion (sound quality) about Aikido lin stage?

I've had positive experience, in fact I have a Broskie ACF-2 buffer that might find its way into a DAC project...

ACF-2 Aikido Cathode Follower Kit

Ray

 

[nautibuoy]

I should be more visible.

Thanks, that's easier to read...

I'm not convinced by your 'three steps' diagram as stage three consists of low pass filters that, I understand, are there to remove out of (audio) band noise.

 

[Frank513]

Hi BK,

DSD only using DSC 1,2 or 3? - Page 4

post 83.

A link for buying pack of parts.
It seems difficult to find seller.

 

[Frank513]

I've had positive experience, in fact I have a Broskie ACF-2 buffer that might find its way into a DAC project...

ACF-2 Aikido Cathode Follower Kit

Ray

Thanx, ok good news!
I read your thread with this Aikido Acf2.
Very interesting your project.
I want build something similar at your.
A pre-amp dac with if possible no op amp, only tube.
And this Aikido pcb looks good too:
Aikido Noval Stereo PCB & Kit

For PSU parts, i aim tube diode rectifier.

 

[nautibuoy]

I read your thread with this Aikido Acf2.

Are you sure you're not thinking of my project with the Broskie BCF?

I've gone with the ACF-2 buffer because I don't think I need gain and its bipolar B+ supply should mean I can do without coupling capacitors.

Ray

 

[Frank513]

Are you sure you're not thinking of my project with the Broskie BCF?

I've gone with the ACF-2 buffer because I don't think I need gain and its bipolar B+ supply should mean I can do without coupling capacitors.

Ray

Yes you right, it was Broskie BCF.
How do you determine is you have enough gain?
Do you plan to drive direct power amplifier?

 

[Frank513]

Thanks, that's easier to read...

I'm not convinced by your 'three steps' diagram as stage three consists of low pass filters that, I understand, are there to remove out of (audio) band noise.

This means stage 2 and 3 should be low passfilter...

 

[nick696]

Hello,
Please advise where I can find kit of PSU for DSC1 DAC.

Thank you
BK

https://item.taobao.com/item.htm?sp...919385.vokYWp&id=521274488924&_u=q2230dl6567c

complete kit is 120CNY (around 18USD)

 

[nick696]

https://item.taobao.com/item.htm?spm=a1z10.5-c.w4002-1190809210.23.qWS4sF&id=523984212824

AK4137 2ch digital sample rate converter (SRC), can convert all signal to DSD256, any one tried this convertor?