flight of harmony PB-1E Owner's Manual

flight of harmony

Eurorack and Fractional-rack Modules

~rev3.3~

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1 Assembled Plague Bearer lter module

High

Low

Gain

Input

level

CV Signal

High Low In Out

f

(h)

1 DC power cable – (euro) 9” Ribbon cable w/10-&16-pin 0.1" connectors

Supply Voltage (min –> max) ±9V –> ±15V

Supply Current (max draw @ ±12V) +12V: 6.5mA –12V: 4.0mA

Input Voltage (@ ±12V) 0Vpp —> 10V

Max Output Voltage

Input & Ouput (I/O) coupling Capacitive (AC)

Output Impedance 3.3µF in series with 1kΩ

Control Voltage (CV) inputs 0V –> V+

CV input coupling Direct (DC)

CV input impedance 100kΩ

Components

(frac)18" 4-wire cable w/ 4-pin 0.156" connectors

Specications

(see text for detailed description.)

pp

±

5V

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Philosophy/What is it?

The Plague Bearer is called a lter, but that is just a description of
the circuit topology, what it can actually do goes way beyond that. It has
been described as a lter, a waveshaper, a mangler, a crusher, and – my

favorite – as an "FSU module"1.

I think calling it a lter may be a bit misleading, but I have no idea

what else to call it. It is a lter, but it does more (all at the same time, really)

excessive phase shifting, waveforming, ringing, formant generation, and so
on. I guess it could be called a waveform modier or enhancer, but those

don't sound good either. I called it the Plague Bearer for a reason.
If you are looking for technical synthophile specs you are out of luck
here. All f(h) devices are designed in accordance with how they sound, not
to achieve mathematical perfection.

The most common question I receive is, "what is the lter slope?"
Honestly, I never measured that. I specically avoided the conventional
approach while I was designing this circuit, so it's very problematic to try
to describe this lter in the normal terms. The slope is directly tied to the
gain of the circuit, making it variable, and the Q is affected by all three lter

controls. The setup is actually a combined High- and Low-pass. The corner

frequencies are adjusted by the controls and can be overlapped completely,
which gives a comb-ltering effect.

The rest is for you to discover.

Changes in Rev 3.3

The 3.3 revision is purely technical, with no changes to performance.
Superuous features and components have been removed to simplify and

speed up assembly.

Specication Details

The Plague Bearer lter module rev3.3 is designed to be as versatile

as possible. Details:

Supply: This design has been tested from ±9V up to ±15V and

works well in this range, although performance specics will vary with
supply voltage. All measurements, unless stated otherwise, assume V

supply

=

±12V.

Output: Maximum V

~

±5V. The modules are intended for use in

out

modular synthesizers, so the output is set to the standard level.

Input: This can physically handle pretty much any reasonable

(e.g., < ±15+ volts

1. F*ck Sh*t Up

) signal you might throw at it. This is why there is an

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