|
 Theremins
are musical electronic instruments, played by moving hands
around a pair of antenas : one for pitch, one for volume
control. The sound produced is the result of the interactions
of two HF oscillators. One fixed, the second one controled
by the pitch antena. Here are some informations on the one
i have builded
The Thereminator1 is based on the TECI 67/74, sligthly modified.
This schematic come from the "Popular Electronic"
article published in 1967.I have replaced all transistors
and fets by common european references, the TIS58 is now a
BF245... It is a discrete solution. I have used two big air
variable capacitors instead of usual miniatures ones.They
are for coarse tuning, 2 big buttons on in the middle of the
front panel. Small knobs, on each sides, are for fine tuning.
The power
supply voltages is a clean +9V DC, a battery will work well
too. Antenas are made with 2 bars of plain steel mounted on
isolated jacks.The
audio output level of the Thereminator1 is very very low !
It require a good guitar amp or a quiet mic/line preamp
to drive it....Bandwidth is around 80..100Hz to more than
20kHz.
Points i have also
noticed :
- The thing will
not work at first time. It seems to be usual for theremin
builders..
- The pitch antena
is rather easy to tune, the volume antena is hard to tune...
- The thing drift
"a little bit" with the variations of temperature
and certainly some other factors..
.
It is a working
prototype... Well tuned, It produce this very typical and
unique sound. I have assembled it during summer 1996, more
by curiosity than to build a real instrument...Today,
i admit it represent one of my favorite synths. May be one
day i will build another one, with a "serious" output at +4dB
and CV outputs...
Thereminator
sound (mp3-173ko)
The background sequence is played by an analog
synth....
|
