neutral labs ELMYRA User manual

ELMYRA v1.3
by neutral labs

Build Guide
Congratulations on your decision to build the mighty Elmyra. Your life
will change forever due to this experience. If nothing else, you’ll be
in possession of this wonderful machine that you likely did not
possess before. Unless, of course, this is not your first build, in
which case I need to tell you that you are a great person.
Panel
First prepare the panel. Place the 4 LED sockets in the positions
shown below and fix them with the nut on the back.

Now put in the 6 touchpads. You must use the plastic washers under the
touchpads on the top side! On the bottom side, tighten the nut and do
not use any washers. The nut must be in contact with the metal film
below.
Then solder the 4 pin SMD header to the back of the panel so that the
pins point towards the bottom edge. Your kit either has an angled
header (right) or a flat one (middle), they both work the same way.

Do not put any of the pots or switches in at this time. Put the panel
aside and continue with the PCB.
PCB Bottom Side
Solder the bottom side components as described below. If polarity
matters, it means you need to pay attention which way you solder the
components to the PCB or panel. Diodes have a black line on them which
needs to match the line on the PCB. Electrolytic capacitors have a
short leg that goes on the minus (“-”) side, and they’re also marked
with a printed stripe on this side. The IC has a dot that must match
the notch in the socket. And this in turn should match the gap on the
PCB. Double check the polarity! If the IC is flipped, you will see the
infamous magic smoke and likely destroy the IC and potentially your
PSU!
(D are diodes, R are resistors, C are capacitors, U are the
potentiometers as well as the IC and its DIP8 socket, S are switches
and LED are, you might have guessed it, LEDs.)

Part
Type
Polarity
matters?
Notes
D1, D2
BAT85
yes
Distortion diodes. Can be
substituted by BAT54. You may
try other Schottky diodes as
well, but regular diodes such as
1N4001 won’t have the same edge
to them.
R1, R15
1 MΩ
no
R2, R17
1 kΩ
no
R3, R5, R7,
R9
47 Ω
no
R4, R6, R8,
R18
4.7 kΩ
no
You can substitute R18 for a
lower value if you like the
power LED to be brighter. Or for
a higher value if you like it
dimmer. Do not go below 50 Ω.
R10, R11, R12
220 kΩ
no
You could experiment with
different resistor values for a
different touchpad response.
Don’t go below 100k or above 1M
though.
R13, R14, R16
10 kΩ
no
C1, C2, C3
1000 µF
yes
C4, C5, C6,
C10, C11
1 µF
yes
C7
3.3 nF
no
C8
4.7 µF
yes
C9
10 µF
yes
C12
0.1 µF
yes

J1
8-pin male
header
no
Polarity does not matter for the
header itself, but for the
cables plugged into it later on!
U1
MCP6002
yes
Solder the socket without the IC
first.
MCU
Itsybitsy
M0 Express
yes
Solder male headers to the MCU.
Place female headers on the
board and plug the MCU board in
for alignment. Now solder female
headers to the board. The MCU is
preprogrammed: You don’t need to
upload any firmware.
Begin by soldering the resistors and diodes.
Now solder the IC socket. It helps to solder one pin first and then
ease it in place. Pay attention to polarity.
Next solder all capacitors except for the 3 large ones (C1, C2, C3).
Once more, polarity matters, except for C7!
Now solder the headers onto the PCB. Break the long female header
strip apart as needed by making a small cut on both sides with a sharp
knife and then snap it along the edge of your workbench. You might
want to use a file to remove burrs and make everything fit nicely.
Then place C1, C2 and C3 into their place and solder. I need not
remind you to check the polarity, right?
PCB Top Side
Now place all the components on the top side of the PCB as per the
table below. Be sure to put the LEDs all the way in at this time. Pay
attention to LED polarity. DO NOT SOLDER ANYTHING YET OR YOU MAY NOT
BE ABLE TO FIT THE PANEL!

Part
Type
Polarity
matters?
Notes
U2 - U11
10 kΩ
linear pot
yes
S1 - S8
SPDT
switch
no
Unscrew the top nut, remove both
washers for now (keep the
knurled washer and discard the
anti-rotation one), leave the
bottom nut in place (tighten it
if needed).
LED1 - LED3
orange LED
yes
The short leg towards the PCB
top edge (flat side of the
printed circle).
LED4
blue LED
yes
The short leg towards the PCB
bottom edge (flat side of the
printed circle).
Now flip all the switches to the down position. Carefully place the
panel on top of the PCB and wiggle it into position. This works best
by slightly tapping the switches one by one with a long object (e.g. a
screwdriver), until they’re all in their mounting holes. Press the
panel into place. Once everything is snug, put washers and nuts

(hand-tight is enough for now) on top of the U2 and U11 pots and flip
everything over.
Push the LEDs all the way into their sockets. Be careful not to bend
their legs.
Solder all the top panel components now. It’s a good idea not to put
on and tighten all the nuts now. Better wait until everything else is
complete, in case you need to troubleshoot.
Connect Panel and PCB
You can now connect the panel and PCB with a 4 pin Dupont cable. Check
the panel and PCB images below and connect as follows:
●panel pin 4 to PCB pin 5
●panel pin 3 to PCB pin 6
●panel pin 2 to PCB pin 7
●panel pin 1 to PCB pin 8
Power Input
Solder 2 wires to the power jack as shown below. Leave the 3rd pin on
the jack unconnected. These wires connect to the male header J1 on the
PCB as follows:

●power jack pin 1 (+5V) to
PCB pin 2
●power jack pin 2 (GND) to
PCB pin 3
Audio Output
Solder 2 wires to the audio
output jack. (Your kit either
has a 3-pin or 2-pin jack, see
pictures.) The wires go to the
header J1 on the PCB as follows:
●audio jack tip (signal) to
PCB pin 1
●audio jack sleeve (GND) to
PCB pin 4
(Almost) Done!
Connect the USB power cable and turn the device on by flipping the
power switch down. If everything is working, the only tasks left are
to put the knurled washers and nuts back onto the switches, the
washers, nuts and knobs onto the pots and finally to secure the panel
to the case using the 4 screws.
Now go create some noise!
If you need help or want to share photos, audio and/or video of your
creations (please do), send a message to [email protected]