NRG pro 4 stereo coder

[montaylor]

Here is the NRG PRO 4 Stereo Coder with Gerbers attached

20250528_193032.jpg

i took the original files and converted them from X1 to RS-274X via kiCad. i have bundled all the supporting documents into the ZIP file.

[radium98]

Master pieace .Thanks.

[Albert H]

That was my design. I have the very first hand-etched build here somewhere. I'll put up a couple of pictures shortly. The very first one of them was built on a sheet of "Veroboard" stripboard, and was huge!

Initially, Stephen was concerned that it uses four supply rails (+/- 12V and +/- 7.5V for the logic), but when I pointed out that we could supply a 12V AC mains adaptor, half-wave rectify in each direction to give +/- DC into the regulators, and use resistors and zener diodes for the logic supply. The big advantages of using a bipolar supply are improved headroom, and a reduction in the component count.

When Stephen heard the stereo that this coder provides, all his misgivings about complexity disappeared. He said that he thought it was - by far - the best coder he'd ever heard. Variants of this design are now made by lots of commercial manufacturers.....!