Page 44 - The Art and Science of Analog Circuit Design

Barry Harvey

Figure 3-7.
Electronics for the masses: the 1960 Knight-Kit audio amplifier. For $70, you get a kit of parts and a chassis
which can become a stereo SOW audio power amplifier. This was a good deal; since labor was expensive, build-
ing the thing at home saved money, and the experience was somewhat educational. More than 100,000 were
sold. From the John Eckland Collection, Palo Alto, California. Photo by Caleb Brown.

board, you had only a 50-50 chance of not damaging it when you tried to
replace a component. You could not make a profit repairing transistor
products.
It got harder to make hobby circuits too. In the mid-60s, printed circuit
boards were so bad you might as well try to make your own. So I bought
a bottle of ferric chloride and tried it myself. For masking, I tried direct
painting (house exterior paint wasn't bad) and resist ink pens. This sort
of worked; I had to blob-solder across many splits in the copper of my
homemade boards. "Hobby boards" were the solution. These are the pre-
etched general-purpose breadboards in printed circuit form. They had
DIP package regions and general 0.1" spacing solder holes. Analog hob-
byists would obediently solder interconnect wires between pads, but the
digital hobbyists had too many connections to make and adopted
wire-wrap construction.
Suddenly construction projects lost their artistic appeal. Tubes arrayed
on a chassis with custom wiring are very attractive, but the scrambled
wire masses of transistor projects are about as pretty as a Brillo pad. You
could hardly see the connections of transistor circuits, and this only got
worse as ICs displaced groups of transistors. I knew a couple of old
codgers who gave up hobby electronics due to failing eyesight. They
wouldn't have had trouble with tube projects. Funny thing was, semicon-
ductor projects still cost as much as tube equivalents but were uglier,
more difficult to build, and harder to debug and tune.
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