Erica Synths DELAY User manual

GUIDE TO ASSEMBLY OF ERICA SYNTHS DELAY MODULE
If you are reading this, most probably, you are
about to build Erica Synths DIY DELAY module. The
module is 45mm deep, skiff friendly, has solid
mechanical construction and doesn’t require wiring.
Erica Synths DIY Delay is hi-fi delay module with
unique functionality typically found on advanced
factory-produced units. We developed a custom DSP
MCU board (comes pre-soldered and pre-
programmed) and delay algorithms for syncable up
to 800ms delays. Selectable Tape and Digital delay,
BPM Sync, Tap Sync makes the module ideal for
nuanced sound design. Furthermore Hold (freezes
the sound up to 800ms), Add (adds several layers of
sound on top) and Reverse (reverses sound in the
hold buffer) functions allow to create crazy sonic
artefacts.
The DIY Delay kit comes in three versions:
1) Set of 2 PCBs + MCU board,
2) Set of 2 PCBs + MCU board + mechanical parts
(PCB connectors and spacer)+ panel,
3) Full kit.
FEATURES:
•Tape Delay and Digital Delay algorithms
•Up to 800ms delay time
•Syncable (clock and tap) delay time
•Delay time divisions and multiplications
•Freeze, Add and Reverse
•Manually and CV controlled delay time, feedback
and dry/wet mix
SPECIFICATIONS:
•Max Delay time 800ms
•Sampling frequency 48khz 24bit
•Audio output amplitude 10Vptp
•CV amplitude (full span) -5V - +5V
•Panel width 14HP
•Module depth 45mm
•Power consumption 97mA @+12V,
33mA@-12V
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The big knob sets delay time from 0 CCW to 800ms CW. When in
Sync mode (clock applied to SYNC input or you used TAP SYNC
button), knob becomes delay time multiplier of divider. Please note
that at low sync rates divider gets disabled, as the max delay time is
800ms.
Select the delay mode –Tape or Digital (no pitch shifting)
Adjust input level to avoid clipping
Use Tap Sync button to synchronize the delay time to the BPM. To
exit sync mode push and hold the button for 2”
Push the Hold button to record an incoming signal in the module
memory buffer. Record time depends on TIME setting, and it will
start to loop the recorded buffer. To exit looping mode, push the
HOLD button again. The LED will lit, when the hold mode is active
When in Hold mode, you can push the ADD button to add more
loops to the hold buffer
9Hit the REVERSE button to reverse delayed signal. It also
reverses all loops in the hold buffer
10 Patch audio signal here
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This is SYNC input –the delay time will be synced to the incoming
clock and you can divide and multiply delay time via TIME knob. To
exit sync mode, push and hold the TAP SYNC button for 2”
12 This is delay time CV input
13 This is the Dry/Wet CV input that controls analogue crossfader
14 This is the Feedback CV input
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Adjust feedback level! In full CW setting the module will go to self
oscillation
Adjust Dry/Wet setting manually! This is full analogue circuit, and
you also can control Dry/Wet via CV
This is the output of the module. We believe, you’ll enjoy
results!
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Take precautions with regard to electrostatic discharge (ESD) safety. Handling components should be done
in electrostatically safe environment. Use personal and workplace grounding. Any discharge (even a minor
one) from body to a component may permanently damage it.
Our PCBs have silkscreened both component values and designators, but as resistors are mounted vertically,
we highly recommend you to print out files with component placement before you start assembly of the
module. And, please, at least take a look on this manual!
Some components are marked as NU (not used) –leave those unpopulated! Some components are
market as OPTION (those are for optional modifications) –leave those unpopulated for now.
ASSEMBLY
1Solder horizontally placed resistors, diodes and
ferrite beads! Pay attention on orientation of
diodes! Also, solder IC sockets!
GUIDE TO ASSEMBLY OF ERICA SYNTHS DELAY MODULE
2Solder ceramic capacitors!
3Solder vertically placed resistors! Here it’s critically
important to follow part placement as resistor
density is quite high.
4Solder electrolytic capacitors, transistors, voltage
reference, resettable fuses and an optocoupler! Pay
attention on correct orientation of the components!
Negative lug of the
electrolytic
capacitor is marked
with a stripe!

5Turn the PCB around and solder potentiometers,
jacks, switch, pushbuttons and trimpots! Make sure
pushbuttons are strictly vertical –use the front panel
as a template!
GUIDE TO ASSEMBLY OF ERICA SYNTHS DELAY MODULE
6This is the MCU Board! It’s developed for this
specific module and comes assembled, pre-
programmed and tested.
7Install female headers on the MCU board! 8Insert the MCU board in the relevant place on the
main PCB and solder female connectors on the
main PCB!

9Remove the MCU board and solder PSU connector as
shown on the picture below! Install ICs –pay close
attention on the orientation of the ICs! When it’s
done, insert the MCU board in its place.
GUIDE TO ASSEMBLY OF ERICA SYNTHS DELAY MODULE
10 Insert LEDs in relevant places! The anode (longer
pin) should go into the square pad on the PCB! Do
not solder LEDs yet!
11 Install the front panel and fix it with few nuts.
Place LEDs in the relevant holes and solder them!
Now, remove the front panel and let’s perform a
calibration!
12 Connect the module to the PSU and connect some
sound source (snare drum or other sound with
sharp VCA envelope will work the best)! Tweak
knobs and make sure the module works! Push the
HOLD button and check, if delayed sound starts to
loop.
Now, let’s calibrate the Dry/Wet crossfader!
Remove audio from the input, set IN LVL
potentiometer all way CCW.
Set Dry/Wet knob all way CCW (Dry). Connect the
voltmeter in DC measurement setting to the TP18
and adjust R107 until you get 0V on TP18.
Set Dry/Wet knob all way CW (Wet). Connect the
voltmeter to the TP19 and adjust R108 until you
get 0V on TP19.
Calibration complete!

13 Install the front panel, fix it with potentiometer, jack and switch nuts! Install the potentiometer knobs!
Congratulations! You have completed one of most advanced DIY Delay units in eurorack! Enjoy!
GUIDE TO ASSEMBLY OF ERICA SYNTHS DELAY MODULE