Page 29 - 2015-12
P. 29
The machine The school wanted three different TV sets
was enor- converted to connect to the VTRs, as well,
mous, it used they wanted provision to be able to record the
two inch wide off-air programs from the TV.
tape on large
reels, which There was no way this could be done on the
seemed to run spot, as it required a considerable amount of
through at a work. I took a VTR and one of the class room
very high TVs to my workshop, where I started on the
speed (actual- design of an interface between the VTR and
ly it was 15 the TV.
Ampex 2” VTR (source: Internet)
inches per
second). The black and white image on the This took quite a bit of designing, with a lot of
monitor looked pretty good (by the standards cut and try involved. The audio was of course
of the day). This was an Ampex quad video no problem, but the video presented a greater
tape recorder (VTR). The word quad referring challenge. How to connect the low impedance
to the four video heads which scanned the tape in/out of the VTR to the high impedance of the
in a transverse (width-wise) direction. video circuitry of the (valve) TV - bearing in
mind the TV still had to be usable for normal
Now moving forward to around 1970, I had TV viewing.
started my own business by then. I received a
call from a well-known school here in
Geelong, they had just bought three video
tape recorders, but could not connect them
to their class room TV sets, could I come
and sort it out for them. Well, always
being interested in new stuff, the answer
was pretty obvious. On arrival, I was
shown one of the machines - it was a Sony
reel-to-reel VTR. The video/audio output
was odd looking squarish multi pin con-
nector. Only video/audio in and out. No
internal tuner for recording off-air TV
programs. At that time, no TV on the
Australian market had provision for direct
connection of video/audio -in fact the only
connector on the TV was for the antenna. Sanyo Reel to Reel VTR
Below: Sony CV-2000 VTR (source: Internet)
The eventual design was a four transistor ar-
rangement on a small circuit board, which
could be fitted anywhere in the TV that space
would allow.
All three class room TVs were converted and
worked quite well, the school must have been
happy with the job, as within a few weeks, I
had two other schools wanting the same job
done, they had bought the same VTRs.
REEL DEALS December 2015 29