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-   -   PCM1704 DAC for sale (http://www.diyaudio.com/forums/swap-meet/17353-pcm1704-dac-sale.html)

Peter Daniel 5th July 2003 07:14 PM

PCM1704 DAC for sale
 
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In order to finance my non-oversampling projects, I decided to sell this David Broadhurst design based DAC. It's using CS8420, PDF1704 and parallel PCM1704 DAC chips (four in total, grade K).
Power supply featuring 6 split bobbin transformers, stack in pairs, for digital part (basically every chip and DAC's analog and digital side and the clock are using separate transformers with it's own full wave, soft recovery rectifiers). Digital PS contain 20 Sprague 1,800u Extralytics, which I believe is a best grade from Sprague.

Peter Daniel 5th July 2003 07:19 PM

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The electrolytics are under PCB with green ERO bypass caps. On the right side there are 2 split bobbin transformers powering analog output stage. Again 6 ERO 2,200u electrolytics are under the PCB containing soft recovery diodes.

Peter Daniel 5th July 2003 07:22 PM

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I'm also using Elma 24 switched volume control with total imp of 500ohm, featuring Holco resistors (smaller values are regular metal film as Holcos were hard to get) shunting to ground and Vishay S102 series element.

Peter Daniel 5th July 2003 07:25 PM

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Here's a rear view of the chassis. There is a provision for switching between 2 sources, yet I didn't install it as I didn't want to compromise the sound quality;)

Peter Daniel 5th July 2003 07:29 PM

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There are four PCM1704 DACs (2 per channel in parallel). They are treated as one as they are piggy backed on ea other with separate bypasses. Ea. channel's DAC analog and digital supply have separate reg. for a total of 8 LT (1085 and 1033) regulators. They are installed under the main PCB. As you notice I'm using Vishay resistors for I/V conversion, most of the resistors are Holcos with some Dales RN60, some MIT bypasses and MIT RTX input coupling caps (despite big size they sounded the best).
All bypass electrolytics are either Panasonic HFQ, Black Gates or Nichicon Gold.

I also did triple bypassing on all chips and the info is posted here:
http://www.diyaudio.com/forums/showt...mods+never+end

Peter Daniel 5th July 2003 07:40 PM

What really suprises me about this project is that although I spent a lot of money and time trying to improve and tweak it, a simple non-oversampling DAC, with carefull attention to PS filtering and reclocking implemented, sounds better than the above posted effort using oversampling approach.

I still believe that this DAC could be further improved, by using different receiver and digital filter, or modifying existing setup and also improving the output stage, but for me it just doesn't appeal anymore.

My recent projects with non-oversampling designs show that this is actually more natural sounding approach and this is what I will pursue currently. I know there are many people who dismiss the non oversampling designs and maybe this DAC would be of interest to them. I'm not posting price and I'm open to offers.;)

takashi 5th July 2003 07:40 PM

HOW much ....... seems the price will be equal to my anual salary...

Peter Daniel 5th July 2003 07:41 PM

Quote:

Originally posted by takashi
HOW much ....... seems the price will be equal to my anual salary...

It depends where you live;)

tbla 5th July 2003 07:50 PM

very nice pics - thanks. :bigeyes:
i have some $$$ to spent....:censored:

later,
troels :grouphug:

bacworth 6th July 2003 02:24 AM

Might be interested can you email me a price and an answer to the following question:

Can it be run on 240v?

thanks,
Brent
acworth@cit.gu.edu.au


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