[sdiy] AN299 and all that !
peteveg at hotmail.com
Wed Jun 12 14:50:04 CEST 2002
>From: "Tony Allgood" <oakley at techrepairs.freeserve.co.uk>
>Reply-To: "Tony Allgood" <oakley at techrepairs.freeserve.co.uk>
>To: <synth-diy at dropmix.xs4all.nl>
>Subject: Re: [sdiy] AN299 and all that !
>Date: Wed, 12 Jun 2002 09:25:29 +0100
> >Anyone remember a Babani book of sysnthesiser projects from about 20
>years ago by a certain M.K Berry ?
>I bought this one at the Breadboard show of 1981. It probably taught me
>more about electronics than any other book. Mainly because all the
>designs suck big time, and you then have to find out how to make them
>better. And why did he not put a single filter of any kind in the damn
Yes Tony, my recollections too !. I remember how I spent an entire summer
holiday in my Dads garage trying to get the one of the two VCO circuits
(not the 8038 one) to work. Needless to say, it was an entire summer wasted
nothing even whistled !. At the time I had very little technical
appreciation of op-amps & transistor circuits , and no scope so there was
little chance of debugging the thing. Looking at the schematic , as I did
recently , really makes you laugh (or cry !) IIRC there is no way the
thing will ever oscillate & even if it did the correlation between input
voltage & output frequency would be very weird indeed !. At the time, I even
wrote via the publishers to Mr Berry, explaining that I had attended to the
PCB foil errors (of which there were many !) and asking for any further
advice some months later I received a letter in which he suggested that I
apply a ve control voltage to the base of the input of the (NPN) transistor
to see if that worked !. Unfortunately I dont think I kept the reply !.
The serious point is that this kind of episode could easily put you off
electronics for the rest of your life when youre a kid building circuits
from a book published by a reasonably credible publisher , when things dont
work you assume its you that is at fault not that the guy who wrote the
stuff is basically a clueless idiot trying to make a quick buck.
I recently discovered that a synth-mad colleague of mine also had a copy of
the same book when he was in his teens. He built the sound generator circuit
in Chapter 1 (based on the Texas SN74189 ?? the of Computer Battleships
fame !). Needless to say it didnt work the chip just got hot !. The
solution in his case was simple the board got taken into the back garden
and adjusted with the ball-end of hammer !!
PS. Complements on a really nice website !
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