My new design ---DAC(SAA7350*2)

[audio-gd]

It can output balance signal .
It use for reference Marantz CD7 ' HDAM

[audio-gd]

More

[JohnW]

Dear Audio-GD,

Lots of hard work there and on your website…

Which Digital filter did you use?

To date, the best sounding DAC designed I’ve built used dual SAA7350. However to gain the best from the SAA7350 the internal OPAMP’s must be bypassed, and great care taken with the Vref to each switch capacitor. Also it must be operated in 384fs Mode.

Needless to say the Clock is critical.

Interestingly, I much prefer the sound of the SAA7350 operating with its internal Switch capacitors over using the external DAC 7 TDA1547… even though the DAC7 has vastly improved measurements???

Do you have a good source of SAA7350? I’m considering designing a CD player using dual SAA7350 and the PMD200 (If I could also find a good source of PMD200), looking for about 2K Pcs. of the SAA7350 & 1K Pcs of the PMD200…

John

[audio-gd]

I cann't found some new IC, so in my DAC, it can use DIP-IC also SMD-IC,, the digital filter it can use most of 28 Pin IC, for example PMD100, SM5803, 5813,5843, DF1704,1700 and any more.
The SAA7350 I've use one PCS in each channels , it's a cheap IC, only need a few dollar .

[audio-gd]

circuit diagram

[PHEONIX]

Originally posted by JohnW
Dear Audio-GD,

Lots of hard work there and on your website…

Which Digital filter did you use?

To date, the best sounding DAC designed I’ve built used dual SAA7350. However to gain the best from the SAA7350 the internal OPAMP’s must be bypassed, and great care taken with the Vref to each switch capacitor. Also it must be operated in 384fs Mode.

Needless to say the Clock is critical.

Interestingly, I much prefer the sound of the SAA7350 operating with its internal Switch capacitors over using the external DAC 7 TDA1547… even though the DAC7 has vastly improved measurements???

Do you have a good source of SAA7350? I’m considering designing a CD player using dual SAA7350 and the PMD200 (If I could also find a good source of PMD200), looking for about 2K Pcs. of the SAA7350 & 1K Pcs of the PMD200…

John

Hi JohnW

You made your dac which used the SAA7350 and you bypassed the internal opamps .

My question is did you use the DOL and DOR output , is this a bit stream which is not PCM and needs only a high order lowpass filter to get the audio .

Regards
Arthur

[JohnW]

Arthur,

Good question,

On the Pink Triangle Dacapo I decoded the BitSteam data outputs to basically generate what is now commonly referred to as DSD (but operating at 192fs as apposed to DSD slower 64fs or 128fs).

This Bitstream is extremely - READ EXTREMILY sensitive to phase noise (jitter), and any form of edge error, and needs to be re-clocked to an ultra low Phase noise clock source before being feed to a LPF. The great advantage of this method is that the output is a low impedance voltage output, that requires no I/V conversion and is filtered (significantly removed of HF energy) before being fed anywhere near “Analogue” circuitry.

I quote “Analogue” because in fact the digital logic that is used to re-clock (Latch) and Buffer the outputs must be considered analogue in nature.

See the Crystal semiconductors data sheet / App. note on implementing the CS4303 for a very in depth discussion on designing a Bitstream (DSD) discrete DAC. However the CS4303 only operates at 64fs (I use its outputs as a semi-decent DSD signal source).

The SAA7350 outputs at 192fs and needs to be decoded to a DSD stream with simple logic (its output is more like PWM not DSD), however this “PWM” needs to be decoded into “DSD” before it takes on its correct none distorted form.

Implementing a discrete Bitstream / DSD DAC with low distortion and noise is NOT a DIY project – requires the greatest of layout and design skill – and SMD components.

When I mentioned I don’t use the internal OPAMP’s – I meant I used off-board I/V’s (as implemented in the Cambridge Audio IsoMagic) – the SAA7350 was never intended to be used in this manner, and using external I/V results in higher distortion, however it sound significantly better.

John

[PHEONIX]

Originally posted by JohnW
Arthur,


See the Crystal semiconductors data sheet / App. note on implementing the CS4303 for a very in depth discussion on designing a Bitstream (DSD) discrete DAC. However the CS4303 only operates at 64fs (I use its outputs as a semi-decent DSD signal source).

The SAA7350 outputs at 192fs and needs to be decoded to a DSD stream with simple logic (its output is more like PWM not DSD), however this “PWM” needs to be decoded into “DSD” before it takes on its correct none distorted form.

Implementing a discrete Bitstream / DSD DAC with low distortion and noise is NOT a DIY project – requires the greatest of layout and design skill – and SMD components.

When I mentioned I don’t use the internal OPAMP’s – I meant I used off-board I/V’s (as implemented in the Cambridge Audio IsoMagic) – the SAA7350 was never intended to be used in this manner, and using external I/V results in higher distortion, however it sound significantly better.

John

Hi John

Its hard to find a data sheet on the CS4303 do you have a copy of this data, being a discontinued part Crystal will not support it any more. Is there still a source of the CS4303 chip.

To convert the "PWM" output to "DSD" what in basic terms do you need to do to it. Can this be done with simple logic do you have you a circuit .

Are there any other chips to your knowledge that provide this signal or have they stopped doing it in current chips as everthing is coming out as a PCM signal. I get the impression that you need a DSP to convert a "PCM" signal to "DSD" is this right.


Regards
Arthur

[carlosfm]

Originally posted by JohnW
... looking for about 2K Pcs. of the SAA7350 & 1K Pcs of the PMD200…

John

John, I don't think you can buy the PMD200 anywhere.
First you have to pay lots of $$$$ for an HDCD license...

I don't know if things have changed, though.
But take as an example the PCM1732 dac from TI/BB.
It's has integrated HDCD digital filter, some brands (like Linn) use it.
But you can't even find the datasheet on TI's web site.

[JohnW]

Hi Carlos,

I have a HDCD license; in fact the Pink Triangle Dacapo was the first product in the world with HDCD... I worked closely with the guys at Pacific Microsonics to insure that our product met there high standards - as it would be the first product to be released to the public incorporating HDCD – and they could not afford bad press….

The BB device is relatively poor by my standards - which is a shame. I would have also liked to have used the HDCD filter in my digital amplifier...

John