100-BIS Tube Amplifier

Grzegorz "gsmok" Makarewicz, This email address is being protected from spambots. You need JavaScript enabled to view it. 
(prepared on 13/07/2004, minor modifications on 23/07/2025)

After purchasing the PS-1 control panel, I acquired a 100-Bis amplifier, which, along with the control panel, is part of the 100-Bis electro-acoustic set. More precisely, the set includes two such amplifiers. The amplifier, whose photos I'm showing, is in excellent condition. The only noticeable damage (aside from scratches, mostly from improper storage) is a small dent in the plastic cover that forms the amplifier's front panel. Why is this dent missing? Well, that's why the amplifier's markings are gone.

The photo presentation begins with four photos of the amplifier with its enclosure closed. It's not a design reference. It's downright ascetic, lacking even a hint of artistic touches that serve its purpose, not mere utilitarian boredom! Frankly, it's UGLY, and I don't like it. It reminds me of an old bread bin enclosure—atrocious.

Photo 1.

The amplifier was manufactured by the Zakłady Doskonalenia Zawodowego. The front panel had markings that had been scratched off by some barbarian. This further exacerbated the ugliness of the case. There were several versions of this amplifier. Below is a schematic of one of them. It's likely the Bis-101 version. It shows semiconductor components, but the tube output stage is likely the same.

And now more pictures. Anyone with strong nerves should watch them.

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After unscrewing the top and bottom covers, the amplifier's interior is revealed (another quartet of photos). And here, I feel much better. The interior is tidy, and the mains and output transformers are quite impressive. Now I know why all my muscles ached as a result of turning the amplifier while taking photos.

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Another look. After removing the back panel and front panel, only the supporting frame and components remain. Here's another quartet of photos of the "naked truth" in four shots.

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Time for details. The following photos show fragments of the amplifier at increasingly greater magnification.

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Now from above and at an angle.

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And now from the bottom. Classic three-dimensional assembly with support (mounting plates with connectors).

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If anyone is not satisfied with the detail of the photographs presented so far, I invite you to see the series of super-detailed photos.

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Now for some details about the mechanical design. As you can see, the designers didn't cut corners. Special brackets were provided for mounting the sockets and fuses. The concept was Mercedes-like, and the execution, unfortunately, traditionally for domestic designs of the time (similar to the Syrenka car).

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Finally, here's an example of how assembly design can be overdone. A multi-level hyperstructure with power assistance. Contrary to appearances, this isn't a mechanical control system for a space probe, but merely a mounting for a power switch and a light bulb. Cool, right?

Photo 37.

And that's all (for now).

I would be grateful for any suggestions and comments regarding the 100-BIS amplifier.

Last updated version of the original text on the Fonar website: July 13, 2004.

Edited by: Grzegorz "gsmok" Makarewicz