DIR9001+TDA1541A Classic NOS DAC

The whole thing started as a simple idea – to design a simple S/PDIF input DAC for my PC. So I turned to the classical chipset – DIR9001 + TDA1541A in NOS mode. I just wanted to keep thing simple and at low cost(compact PCB). So eventually the thing grew up to a group project with many people sharing opinions on the mater.
The whole discussion thread is here(Bulgarian language):

https://www.bgaudioclub.org/forum/viewtopic.php?t=22012

Since some people suggested to make it possible to use TDA1541(non A) DAC chip the project was altered this way. The interesting thing about TDA1541(non A) is that it allows a master clock to be fed directly to pin 4. This one accepts 11.2896MHz clock frequency. In TDA1541A non such thing is available.

From TDA1541 datasheet:
“A separate system clock input (SCK) is provided for accurate, jitter-free timing of the analogue outputs AOL and AOR.”

So the PCB was designed to allow this mode, should a TDA1541(non A) was used. For some reason Philips had decided to turn that feature off in their later TDA1541A DAC chip. Here is how it should be implemented according to a Philips application note from 1985 :

The application is a bit misleading. The SAA7220 chip actually outputs 11.2896MHz at pin 9.

As for the analog section. It’s of course a pure classic. Opamp based I/V converter, followed by an active low-pass filter. Nothing fancy here. The project uses one double opamp (NE5532) per channel. Of course a DC null correction is used at the DAC chip outputs. Despite that a output coupling capacitor is paced on the PCB.

Here are some pictures of the PCB:

Almost completed project forum mate Stanislav

Higher end implementation from forum mate Nikolay Kolev

The final version of the schematic is available for download HERE.

UPDATE:
I am adding the gerber files for this project. To download click here – >>>[ LINK ]<<<

Update 19.08.2012
The project was further tweaked by a fellow Plamen Todorov by adding a ECC88 tube stage. More info on this HERE

WARNING – this project is provided to the DIY community for free and is intended for personal usage ONLY. Therefore a commercial usage is NOT allowed without author’s exclusive permission!!!

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