Fidelity Designs LTD

The Ultimate DAC.

I had been designing some digital to analogue converters for my own use and was getting positive feedback on the sound quality. This encouraged me to go all out and design and build my Ultimate DAC. The DAC is designed by myself from the ground up and everything is fabricated by myself.


An overview of the Ultimate DAC.

Posted on by Ben Lamb -

After designing and building a couple of DACs based on the Wolfson WM8740 chip I decided to design and fabricate a no holds bared WM8741 based unit running two DAC chips in dual differential mode. The design philosophy was to separate all the power supplies so each part of the circuit had its own transformer winding, rectifier, capacitor choke filter, regulator and in the case of most parts of the circuit a secondary low noise shunt regulator/filter circuit. The design was also dual mono with a DAC for each channel and also a separate opamp for each channel to give a standard unbalanced output.

The design uses five PCBs and includes a mains filter before the transformers. A Burr Brown DIR9001 chip handles the SPDIF functions and the DAC has infrared and coax input. It can also work on all bit widths and sampling rates going up to 24bit and 192khz. The DAC is auto switching so it can switch between different types of content effortlessly.

The DAC is a revelation for the listener, its design ethos mirrors how it sounds. The extra detail you hear in your favourite CDs and the separation of different instruments and vocals is stunning. This piece of equipment never fails to put a smile on my face and realy is something very special. I built two and one is housed in a 1u rack which matches my CD player and is an invaluable tool for demo purposes and also back to back analogue/digital comparisions. Another unit was built in an enclosure fabricated by myself.

Ultimate DAC prototype.

When I get the time I do a lot of research and development. I have many potential products detailed but being a one man outfit I just don't have the time to bring them to fruition. Maybe one day when funding allows I could bring these products to the marketplace.

I am always thinking of new ideas as design is my passion but many hours are taken up with the process of fabricating products.