My first contact with a Nelson Pass project was the zen variations 1. There he writes about several hundred permutations of the same single stage design. At that time I could not imagine how this was possible and I was thrilled by the idea of using light bulbs as resistors.

Now, two years later, after reading everything I could get, filling my working place with electronic parts, building a zen light, Zen 2 and a Zen 2 with Zen4 buffer, I'm able to design my own little permutation of the BoZ. I like to find new ways.

The changes made are: - replace R104 1k and R108 100 by 11 little, orange light bulbs, each one has roughly 90 Ohms, worked as good as with resistors and looked nice - replace the biasing network with 4 green LEDs - on the PSU replace Zeners by yellow LEDs and R1 by a CCS made with 2 blue LEDs , 2 Transistors and 3 Resistors For the details consult the schematic.

The big cans on the pictures are Siemens B25834 MKV 6,8uF, one as input coupling cap and 2 parallel as output coupling caps. After testing a lot of different types, these sounded best to me.

Besides the transformer, the IRF510 and the Audiofad professional pot, all parts are bought on ebay or taken out of broken computer power supplies. Wires are silver or teflon isolated wire-wrap type. The output-cable is a piano type from tnt-audio.

The case is made of a 3cm thick granite plate, different aluminum bars, Plexiglas and semi transparent foil taken out of broken TFT-displays.

I like the colored gleam very much an the sound is terrific.

My thanks to Nelson, the PassLabs crew, the people at diyaudio, my friend Adrian and my wife for her patience with my hobbies.

Daniel Fuchs

daniel.fuchs@diallery.com

More about the eboz in german: http://www.diallery.com/members/df/eboz