BLM CMOS FX Processor Mk2

Blue Lantern Modules

CMOS DRONE Synth

Model: BLM CMOS FX Processor Mk2
Width: 16hp
Current: +35mA,-34mA

PCB Stack: 1 level. Skiff compatible.

What does this do?
This module has all the internal circuits to complete a voice: sound generation + envelope generation + amplifier control.

The sound generation is interesting. The core is using 3 CMOS based oscillators that are performing exclusive 'or' logic.
This is known as 'XOR' ring modulation. This entire circuit is being voltage starved, a technique common among the advanced circuit bending hobby.
For example, portable vintage toys that use batteries sound different as there batteries loose voltage. I designed a CV controllable
circuit that simulates the 'dying batteries' scenario.

This is where the product's name comes from: CMOS FX Processor. Incoming audio is internally conditioned to be those dying batteries. To my knowledge, I don't think there is any other euro format product that uses this technique.

-CMOS FX INPUT jack has a capacitor on it's signal path, making this an AC input.
-MOD INPUT jack is a DC signal path.
-FM INPUT jack is also a DC signal path, but with level control (attenuator).

Envelope Generator
This is a digital based 1 shot circuit, that has 8 wave forms. The decay knob controls the tail of the envelope. There is no parameter for attack.
Some of the wave forms have set attack times if you require some 'fading' in on the control.
-Regeneration 'REGEN' parameter is a feedback. This controls the looping of your envelope.
-Delay parameter controls the time until the next 1 shot of your loop.
-Decay knob needs to be adjusted as you experiment using Regen and Delay parameters. Shorter decay times work best and make the looping faster.
-Envelope Output is 0-10V.

Amplifier Control
The internal circuit is an OTA based '13700' VCA design.
-Accent input jack is a POSITIVE only conditioner. For example if you patch a -5/+5v signal, only the +5v portion reaches the VCA control.
This is good for making the audio louder at given intervals, but not making the audio 'mute'.
-VCA CV input jack is a direct DC coupled input. This will make the audio fade in and out of volume. Both positive and negative values make it to the VCA control.

How to use this module.
For best results you will need a sequencer or sample and hold from a digital fancy module. You can practice first by patching this to the 'FM' input and find your sweet spot with its level.
You will need to patch a 'tempo' to the trigger or you can use the W Pulse clock to trigger this product.

Once you got the hang of the module, make a sequence-based patch with your other modules. Use the CMOS FX Processor at the end of the audio signal path chain to 'Process' your audio.
Your going to here some bizarre techno. If you have a scope, the wave forms on the output are really crazy to see.