BLM Lucky 7 OTA VCF
Model: BLM Lucky 7
Current: +69mA -68mA
PCB Stack: 1 Level, Skiff compatible.
Module type: analog filter, sub harmonic generator, internal vca, white noise generator, (self) oscillator
What does this do?
This particular product is my take on the vintage analog filter found on the Roland SH1 Keyboard. Some key differences from the original
are low end correction on the resonance path (audio level would drop), with voltage control, and I used a modern exponential converter.
The bass frequency will retain nicely on this modern version. No more audio level drop. The 'RCV' can be used to simulate Band Pass sounding tones when used with audio rate external sources..
I also included the famous feedback patch that lucky users of the vintage keyboard would do. Users would patch from the headphone output back into the filter external input.
I duplicated the original discrete headphone circuity and internally patched it for you. All you have to do is turn it up with the 'FBK' knob. Small settings go a long way with this.
It can get strange with too much feedback, in a good way.
24db Low Pass Filter.
(2) Possible External Audio inputs.
(1) White Noise Generator, Switch Jack internally patched to AIN2 input jack.
(2) Sub Harmonic Generators taken from the SH101 circuitry. Both are accessible by level knobs.
(1) Voltage Controlled Rez, with auto low end level correction.
(1) 1V per octave 'Expo' input.
(1) Linear FM input. Best used during Filter Self Oscillation duties.
(1) Bi-polar FM Attenuinverter. Best used with an external envelope generator.
(1) Internal VCA with 2 possible CV inputs. VCA knob is a manual offset to 'open' the VCA.
What you get:
All you need is a vco, and envelope generator to complete a compact analog mono voice.
If this was literally your first and only module, it is possible to make sound and noise for entertainment.