- Logan string melody
The Logan String Melody was a "string machine" produced in 2 versions from 1973-82. Within Italy it was sold under the Logan brand, and outside Italy it was distributed by
Hohner .Comes in a heavy wooden case for stage purposes - weighs 23 kilos. full
polyphony with VCA for each key. and an amazing jarre-like chorus.
has 4 octaves split by the half. each half contains a 3-octave mixer and an attack & release (shown as sustain) fader; on the lower half you can add 2 monophonic bass sounds.
the 1st version should be a dozen beta-versions or so with changing modules, the 2nd called as 'string melody II' is the final version.
the 8" is called cello, the 4" viola and the 2" violin; bass is 16", perc. is a decay bass.technical inside:
the sound begins its way at a high frequency square generator, then follows to the top octave divider mostek MK50240N. it does the highest octave. the lower 5 ones are divided by 9 7-stage dividers SAJ210. then the square passes the simple VCA built as a diode gate with CV - works only on square - and a pulse conversion. then the mixer, the chorus, a filter and the output stage.
the 16" monophonic bass sound - only on lower half - has no VCA but low-filtered and through the chorus, too;
the perc. bass is well-low filtered and has an attack of 30ms and a decay of 700ms, no release. simple gate VCA w/ a 47µF capacitor, the filter is behind it.
chorus: 2 modules - the dual LFO and the triple delay-line.
LFO: 0,6 Hz and 6 Hz mixed together and put out as tri-phase of the low LFO to the delayline.
delayline: 3x TCA350 - a bucket chain of 256 MOS double transistor stages which the audio signal is sampled by a high frequency, which is modulated (FM) by the dual LFO so the output samples are shorter or longer - and this makes the curly sound.
presets:
O: chorus & mixer
acc.: accordion as plain out (w/o chorus) & mixer
solo: fast LFO - tremolo (FM), low LFO - vibrato (AM) w/ chorus & mixer
orch.: full orchestra w/o mixer and bass
organ: only low LFO chorus & mixer
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