Asteroid Mini User manual

Asteroid Mini Synthesizer Reference Manual.
Here is a picture of the module to make sure you got the right reference manual.
Asteroid Mini Synthesizer
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Format: Euro Doepfer compati le, 3U height (5.05")
Power Current Consumption: +108mA, -83mA
Depth: less then 45mm
Circuits involved: VCO, VCA, Envelope Generator, Su Harmonic Generator, Noise Generator, and trigger
striking circuit.

Asteroid Mini Synthesizer Reference Manual.
Here is a lock diagram of module:
What does this module do?
This module is a percussive synthesizer similar to the voice of a korg ER-1 drum machine. I used that
groove ox as a model on how to internally connect the different su modules found inside the Asteroid
Mini Synth. I was not shooting for a clone, it just helped me achieve an understanding of how to make a
great percussive mini synth. This module is 100% analog signal path, where as the korg ER-1 is a dsp
ased simulation.
-The internal vco was taken from my Transistor Pyramid VCO. That uses a discrete transistor circuit to
create a nice triangle wave. The sine shaper is also transistor ased and sounds fantastic.
-A ooster circuit was added to achieve the ‘techno drum sound’ with ease.
-Part of the ER-1’s magic was the delay effect. On the Asteroid Mini Synth I used a PT2399 modern IC
chip to simulate ucket rigade effect (delay).

Asteroid Mini Synthesizer Reference Manual.
*Tune and Fine kno s: use these to adjust the vco pitch, the led’s to the right give you a visual of how
fast the vco is going.
*The toggle switch ‘1UF and 9U4’: these values determine the range of the Decay envelope generator.
The la els represent actual capacitor values. When it is set to the middle position you are using 0.47uf
capacitor. This is good for short drum sounds. 1UF is considered medium length. 9u4 will give you a long
decay range.
*To the left ‘VCA’ small lack kno : this acts as a gate control. When it is turned fully counter clockwise
it is ‘closing’ the sound. You should not here sound at that position. As you slowly turn the kno
clockwise you give the vca a linear curve on how it will react when the red push utton or trigger input is
used. The vca circuit will also overdrive creating nice over tones depending on the vca kno position and
the oost amount. There is only one Decay generator. The ‘Decay’ kno directly affects the vca kno .

Asteroid Mini Synthesizer Reference Manual.
*Mod VCA: to the right of the vca kno is an attenuated level for jack input ‘ModV’. Use this to add
more expternal control to the VCA.
*Lin small lack kno : this is a linear fm input for the VCO. I set it up with a really strong range. To give
you more insight, the original value was 100k resistor, I installed a 1K resistor instead. What this mod
does is let you modulate the vco into hypersonic metallic sounds if the kno is turned fully clockwise. I
recommend when not in use to turn it ack to ‘0’. At times it came fine move the pitch of the vco even
with nothing patched into the ‘Lin’ jack, that is normal ehavior. Like mentioned just turn it to 0 when
not in use.
*Su small lack kno : this is the level for the internal su harmonic generator. It is mixing 2
su harmonic frequencies at once. It is est to use this when the vco is at medium or higher frequency.
*Boost small lack kno : this is the internal ooster circuit to give the VCA an overdrive overtone. This
circuit is not included when you use the output jack ‘SUM’. If you patch an external signal from another
module into the “Ext VCA” input jack the signal flow is: ooster->vca->delay fx-> perc output, ¼” jack.
*Repeat and Time kno on the left: those are parameters for the delay fx. You will here no change if the
fx toggle switch is not engaged (set to FX), and the fx level kno is not turned clockwise.
*SYNC small lack kno : This is varia le sync circuit only found on the lue lantern triangle core design.
When not in use it is est to have this also set to zero, it is strong stuff. Use the ‘Sync’ input jack to
patch. Experiment with an external vco to create some izarre synchronizations.
*MOD fm small lack kno : this is an exponential 1v/per octave level in relation with the MOD input
jack.
*Toggle switch Triangle and Sine Waves: use this to select the vco output wave. You can also turn off the
triangle and sine wave from reaching the ‘Sum’ mixer when set in the middle position. The ‘Off’ can e
used for example when you only want to mix the Noise generator, square wave, or su harmonic square
waves.
*Pop kno : This is the internal striking spike hard wired to the vco. It creates a small punch sound when
turned clockwise. It is good for percussion sculpting.
*DEPTH + and – kno : this is a ipolar modulation kno for the internal vco. It is hardwired to the decay
kno . When it is in the + direction it will give the vco an impression of a kick or kraftwerk zap. When the
depth kno is used in the negative position it makes a wo le effect.
*Noise kno : this is the level kno for the internal noise generator. There is also a trimmer on the ack
of the module near the ottom left. It determines the loudness of the noise generated. By default I set it
up low. If the 500k trimmer is set up too loud it can cause ‘ leed’ in the entire Asteroid Mini
Synthesizers output.

Asteroid Mini Synthesizer Reference Manual.
*HPWN and WN toggle switch: this toggle switch selects etween ‘high pass white noise’ or ‘white
noise’. The difference is like right and dark sound.
*Decay kno : this determines the length of the envelope generator. You will only here the effect of this
kno if you push the red utton or have something patch into the trigger jack input. Use the top toggle
switch to setup the range.
*FX level kno , and the FX toggle switch: the FX level kno mixes in the wet fx signal with the dry signal.
The toggle switch will kill the fx.
*Noise and Square wave select toggle switch: this switch is in relation with the output jack right a ove it.
When Square wave is selected, you use the Square wave level kno to determine the ouput loudness of
the square wave. When you select the noise wave, it is outputting direct, meaning the noise level kno
does not effect the output level.
*Square wave use: this is not hard wired internally. If you want to use the square wave as a percussion
source you need to manually patch it into the ‘Mix’ input jack. You can also patch the square wave into
the PCV to create a saw wave.
Jack outputs and inputs
*PCV: this is the direct ‘PITCH CV’ input jack. Use these for 1v/octave control.
*MIX: this jack is used to mix an external signal with the internal vco, noise, and su haronic generator.
You can for example com ine two Asteroid Mini Synthesizer modules, or a lue lantern TPC vco to
create a chord.
*RCV, TCV, LCV: these are cv inputs to control the delay fx parameters. Repeat CV, Time CV, Level CV.
*DRY and Perc output. Dry output does not have the delay fx in the chain. Perc output jack has the final
Delay FX in the chain. Both can e used simultaneous.
*1/4 Line level output jack: this also has the final delay fx in the chain.
Trigger input and thru jack
The Asteroid Mini Synthesizer is a percussive module. In order for the module to make such a snappy
response and return the pitch ack to a reference point it must use a trigger input as oppose to using a
gate input. If it used a gate input as the internal circuit it would of remained high or low and the overall
perception would not have een the same (percussive). It would have een another mono synth.
What does this mean?
If you play a key oard and use a midi to cv converter, for est playing style you are going to have to
trigger notes one at a time, not over lapping. If you are using another module like an LFO there is no
pro lem. The pro lem only lies when playing poly notes and they are over lapping.

Asteroid Mini Synthesizer Reference Manual.
The ‘thru’ jack will output the trigger that was inputted and can e used to trigger another module in
relation to using the on oard red push utton.
Using the Asteroid Mini Synthesizer with an external filter module.
In order to process the sound generated inside the module with an analog filter use the ‘Sum’ jack
output. Patch that into a Blue Lantern Diode Operator Station VCF and then patch the output of that
ack into the Asteroid Mini Synthesizer’s ‘EXT VCA’ input jack. This is similar to a send and return
configuration. You can also use the Asteroid Mini Synthesizers’ ENV output jack to control the cutoff.