There were several EC designs made from 75 to 80, the first period. Several of these never made it into production.
On the following pages details of these designs are given, as far as we have been able to recover them. Some schematic details, some of the story behind and the reason for their development, and some technical goodies and possible, a hint or two.
One of the interesting designs were the "Regulated 25W" amplifier. This amplifier had regulated power supplies for both the pre- and power stages. IT made away with all the ripple, and provided high speed power to the amplifier. It sounded good ! But, the heat .....
Another interesting case was the "May 78" preamplifier. I don't remember why it was called the May 78 preamp. It was designed in the period January to July 1978. At Electrocompaniet this preamp was named "Model II".
The School Amplifier as we called it, is not really an EC design. I took an engineering degree at that time, in parallell with my work at EC, and together with a friend, Øystein Klevhus, at that school, we did a project - of course a power amplifier design. It was not intended for production at all, but it was sponsored by EC, as all components, instruments etc. were EC stuff.
In 1977 we were approached by the Norwegian Broadcasting Corporation, or in Norwegian - Norsk Riks Kringkastning (NRK) and asked if we could develope a professional preamplifier for studio work. It should have differential input and output. Of course, to us this meant, no transformers. The electronics were completely differential all through. The preamp had passive equalization, a lot of transistors, and sounded VERY good. We will try to locate the schematics and put them up here.