flight of harmony The Sound Of Shadows User manual

Eurorack Module
v 3.0

Specications
Supply Voltage ±12VDC1
Supply Current (max draw @ ±12V
& +5V) I+12V= 19mA I-12V= -15mA I+5V= 21mA
Supply Current (max draw @ ±12V) I+12V= 41mA I-12V= -15mA
Max. Input Voltage (@ ±12V) 10Vp-p
Max. Output Voltage (@ ±12V) 6Vp-p
Input & Ouput (I/O) coupling Direct2
Output Impedance 1kΩ
Control Voltage (CV) inputs ±Vsupply
CV input coupling Direct
CV input impedance 100kΩ
1) Has been tested and performs well with supply voltages from ±9VDC to ±15VDC.
2) I/O jacks are direct-coupled. The Delay circuit itself is not. A DC signal at the input will be
available at the Clean, and Mix outputs, but not available at the delay output.
Components
1 Assembled Sound of Shadows digital delay module
1 DC power cable – 9” Ribbon cable (Doepfer standard)
2 M3x0.5x6mm stainless-steel machine screws
2 M3 Nylon washers
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What is it?
The Sound of Shadows (SoS) is a voltage-controlled (VC) digital delay module
based around the PT2399 echo IC1from Princeton Technology – which was, by
the way, originally designed for Karaoke equipment.
As with all f(h) products, the SoS was engineered towards maximizing
functionality while keeping cost as low as possible. If some aspects of the unit
seem awkward, it is most likely due to this. The goal is to make unique, useful,
enjoyable, and affordable instruments, not just hoover2out your bank account.
And remember: every instrument has its quirks and unexpected aspects,
so RTFM3! All the way through! Specic quirks are mentioned in the description of
the particular feature they apply to, so please read this through before emailing!
Feature summary:
x VC delay rate.
x VC feedback level.
x Signal input.
x Clean, Delayed, and Mix outputs.
x Feedback loop insert jack.
x Multiple units can be chained together via rear header.
x Chaining cable available separately.
Controls
Rate: This controls the delay clock rate, which in turn controls how fast the
1) Integrated Circuit
2) Hoover is a company that manufactures vacuum cleaners.
3) RTFM = Read The F*cking Manual!
level
DELAY
Input
Chain
Delay In
x -1
FEEDBACK
GAIN
Clean
out
Mix
out
Mix
Delay
out
Insert
jack
EXT
Sound of Shadows v3 owchart
Chain
Delay out
x -1
Chain
Insert In
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delay steps through its memory array and thusly the amount of delay. Clockwise
rotation increases the rate (which decreases the delay time), counter-clockwise
decreases the rate (which increases the delay time).
Feedback: Controls how much of the delayed signal is fed back into the
delay cell. Feedback is what creates a reverberation or echo sound – multiple
repetitions of an acoustic event. Clockwise rotation increases the amount fed
back, and thus the number of repeats, counter-clockwise decreases the amount.
The nominal operating area is between 6:00 and 9:00 during normal usage.
More than this will set up a self-propagating feedback cycle that will quickly get
out of hand.
Insert: This is the attenuator for the feedback loop insert jack. The jack is
situated between the delay cell output and the feedback cell input. The feedback
cell input is calibrated for the output of the delay cell, which is around 1.5Vp-p
maximum, and most standard signals inserted here will overload the feedback cell
unless attenuated, hence the Insert attenuator. Turn clockwise to increase the signal
level, counter-clockwise to attenuate.
When not using the Insert jack, it is recommended to keep this control turned
fully clockwise, to the maximum position. Otherwise, you are attenuating the output
of the delay cell, which will affect everything else further down the signal path.
Input: This is the input level control. Just like a volume knob – clockwise
increases level, counter-clockwise attenuates the signal level.
Mix: Um, yeah. Guess what this controls? The balance of the mixed signal
at the Mix output! Seriously, this controls the mix between the Clean and Delay
signals at the Mix jack, really!
Jacks
The jacks are grouped by the type and direction
(into or out of the module) of the relevant signal.
CV in
Rate: Quirk warning: Rate CV behavior is
inverted. Negative increases rate, positive decreases.
If that bugs you too much, just think of it as the delay
CV input and the issue magically disappears! Positive
increases the delay, and negative decreases the
delay.
Feedback: This works normally, positive CV
increases feedback, negative decreases same.
Signal in
Input: This is kind of important for a delay unit: you need a signal to delay,
or else they’re somewhat dull effects. This is the jack where that signal is input
into the delay.
Insert: This is the feedback loop insert breakjack. Inserting a plug here will
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disconnect the output of the delay cell from the input of the feedback cell, with
the inserted signal now going directly to the feedback gain cell.
One use for this is to insert an effect – or even another delay unit (yes,
they can be daisy-chained quite effectively) – into the feedback loop. To do
this, patch the Delay out into the desired effect, and the output of the effect into
the Insert jack. You may need to adjust the Insert level control (see above) for
best sound.
Output
Clean: A buffered and inverted copy of the input signal.
Delay: The buffered & scaled output of the delay cell
Mix: A linear mix of the Clean and Delay signals, the balance of which
is set by the Mix control pot.
Chaining Header
The rear header is to chain two or more SoS together
for longer delay times, and other effects, without using up
the front jacks. There is one output and two possible inputs
(See g.1 for graphical locations of the connection points.):
Delay out: Buffered, inverted, delay signal output.
Delay In: Equivalent to the Input jack. Chained signal
is summed with input signal and sent directly to delay cell
with no attenuation (see following Chaining Delay Trimmer
section).
Insert in: Equivalent to using the Insert jack, but without breaking signal path.
Chained signal is summed with output of Delay and Insert, then sent through the
feedback gain cell before entering the delay circuit, allowing signal attenuation.
Chaining Delay Trimmer
During development, it was noticed that overdriving the delay input of
the second Sound of Shadows resulted in some delightfully horric mangling,
screeching, and generally cacophanous sounds. However, it could not be the
default because it also drove the output up to ±10V, risking damage to connected
modules. This trimmer is the compromise.
Want a dangerous, horrendous, mess? Turn it all the way down (counter-
clockwise). Want a safe, factory-friendly setting? Turn it all the way up (clockwise).
In between? Put it where you want it. To repeat, however, and in ofcially-legal-
sounding words4:
WARNING: USE AT YOUR OWN RISK. USE OF THIS FEATURE WILL CAUSE
OUTPUT LEVELS THAT ARE NOT COMPATIBLE WITH EURORACK STANDARDS
AND WILL DAMAGE SOME MODULES, AND MAY DAMAGE THE REST. FLIGHT
4) A.K.A.: Royal Capslock
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OF HARMONY CANNOT ACCEPT RESPONSIBILITY FOR ANY DAMAGE
CAUSED BY USE OF THIS FEATURE.
The Chaining Delay Trimmer only affects the chained signal connected to the
Delay In pin and has no effect on unchained devices.
Power
The power connector header is a
2x8/16-pin shrouded box header which
accepts the standard Doepfer power
cable. This header style is polarized,
meaning the connector can only be
inserted one way, to prevent connecting
the power backwards and damaging the
unit.
This assumes that you are using either
the supplied cable or one manufactured by Doepfer.
Looking at the rear of the module, the negative supply (red stripe) is on the left,
positive supply is on the right (see g.4).
+5V Source Selection
The Header marked “+5V” allows you to select whether the +5V is supplied
by the main +5V power bus or derived internally from the +12V supply. Set the
shunts in the position indicated by the PCB legend.
Stuff
A big thank you to those who have sent in suggestions and comments, keep
them coming!
Comments, samples, suggestions, complaints to:
ight@ightofharmony.com
Drawings and designs ©2022 ight of harmony, LLC.
http://www.ightofharmony.com
We are tomorrow’s shadows...
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