RelaiXed -- Balanced pre-amplifier

RelaiXed is a high-end audio preamplifier for the DIY audio hobbyists, featuring:

Its design is first published in the Dutch Elektor Audio Special 2 of December 2007. About year later the German edition appeared: The 'ELEKTOR Sonderheft AUDIO 2' was published on November 19, 2008. This project was a cooperation between Sander Sassen and myself, Jos van Eijndhoven. An initial small set of prototype PCBs was quickly gone. Two later sets of PCB each had small updates to the design.

Currently, these PCBs are not available anymore. A redesign has been made with significant updates to all of the analog design, the digital control design, and the firmware. For the new design see the RelaiXed2 page.


Building RelaiXed

The design uses easily available components, that you can buy at your favourite shop. (Sorting out piles of components is not the way I prefer to spend my audio hobby time.) The available design documents relate to different versions of the RelaiXed design, which received small updates over time both in hardware and in embedded microcontroller firmware:
Board revision / Firmware revision: Design Documents:
Mar'09 / Jan'09 user guide, schematics, components(pdf), components(xls)
Mar'08 / May'08 user guide, schematics, components(pdf), components(xls)
Dec'07 / Dec'07 user guide, schematics, components(pdf), components(xls)

A collection of datasheets of used components: zip document (Large doc, just as background info, probably you won't need this.)

You can see a few more photos from building my own RelaiXed in my RelaiXed Picasa album. Furthermore, there is a forum dedicated to RelaiXed, allowing builders to exchange ideas and questions with each other.

A professional qualtiy PCB was made, 140x291mm, double-sided, with text annotation and gold-finishing of solder areas: (top view, bottom view. I will seperate the main PCB from the front-mount PCB for you.)

Early summer 2009 we have made a number of RelaiXed housings based on a hifi2000 'slimline' cabinet, by having a metal company rework the frontpanel for an embedded dark plexiglass window and a volume knob. See this forum message (drawing, foto1, foto2). Otherwise, it seems possible to send the nice (brushed) Hifi200 frontpanel to Schaeffer-ag for your personal processing.

Thanks for your interest,
Jos van Eijndhoven
May 13th, 2010

Jos van Eijndhoven
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