[sdiy] RE: how it all started

[René Schmitz]

Hi all,

oh yeah, those childhood memories.... Similar ones on my side:

I had my first KOSMOS Kit when I was 6 or 7. But I was too young to
really understand it. I still have the red rectangular board on which
you made the circuits, and the instruction manual. I always fried the
transistors, when I tried to switch 6V 3W Lightbulbs... :-P

Well, the interest faded, due to a lack of understanding... Then when I
was about 12 I came across a book about Electronics, and this was what
retriggered my interest. THere was a basic course from resistors and
lightbulbs, via BJTs, then to FETs, there was also a chapter on Opamps,
and finally digital circuits. But this was only a book, and no parts or
anything to build the things with. So I bought the first Busch 2060...

Later I also had one Philips EE20xx and a lot from the Busch system,
slowly upgrading from the small 2060 to the big 2070. I later also had
the 2072 amplifier and the 2074 (I think) which was about infrared
optoelectronics. That had a 555 timer chip module, and a 567 tone
decoder module that you could use for IR transmissions with an IRED and
a phototrannie. Then finally came the "Synthesizertechnik" (can't
remember the number, 2075 or so) which was basically a module with a
76477, two transistors and six or eight trimpots (with axes that
plugged into the trimmers), I still have that module, yet the chip is
taken out to make some experiments with it. I think I also still have
the manual for that. You could do lots of "outer space" and "police
siren" experiments with that. There were also circuits for "Accordion"
and "Piano" (yuck..) sounds.

Well, then computers got into the way of Electronics, and I spend more
time on that. But that changed again, when I started to play bass
guitar. All of a sudden there was the desire to play with effects and to
build amplifiers. Synths were still much of a mystery. Despite the Busch
Kit, which had no filters, and no real voltage control. About that time 
I got a copy of the Allen Strange book, so I knew about the concept of
volts per octave voltage control, yet I had no idea how this could be
implemented.
That changed until I had to take an electronics lab course at the uni.
On one of the Experiments, one would build a simple exponential sine
VCO, a sawtooth LFO, a rectifier and some fixed filters. (Each part was
done by a small group.) The LFO was used to sweep the VCO, which then
was coupled to the filter, whose output was rectified. Then you could
make a bode plot on the scope.

Shortly after that, I made an Altavista search about synthesizer
schematics, the page from Rick Jansen turned up, and that is how I got
here....

jhaible at debitel.net wrote:
> Looks familiar! The Bush had 4 (four) transistors included, all BC238.
> No pnp's - I guess the analogy in the booklet would have been too
> difficult with water also flowing upstream. (;->)

Oh, right. :-) But they had those strange pseudo push pull amplifiers on
the radios, which I never quite figured out at the time.

> I envied a friend who had the Philips system, because it could use
> normal transistors instead of mounting them to large plastic sockets.
> And it had included a BF194 as well, which helped a lot for the radio
> and HF experiments.

Hmm, I always liked the radios one could build from the ZN414
"MW-Radio-IC" of the Busch System. That was way simpler and better than
what the usual two transistor radios of the other systems had to offer.
(The MW-Radio from that Kosmos Box, was especially  odd, you had to tune 
it, by varying the coil, and change the capacitors manually....)

Cheers,
  René