SyntherJack 4sum User manual

4sum
portable audio mixer
assembly instructions*
v0.95
by SyntherJack.net
*I've tried to keep it short and informative. obody reads manuals.

Main features:
•4x mono inputs,
•1x stereo (double mono) output,
•long battery life (average 100 hours),
•output in phase with input,
•high quality components,
•designed for portability,
•LED on/off indicator.
Mechanical data:
•size:
◦without knobs : 93 x 60 x 29 mm,
◦with knobs : 93 x 60 x 35 mm,
•weight:
◦ without battery: 90 g,
◦ with battery: ~120 g.
Electrical data:
•max. input signal level: 6 Vp-p,
•max. amplification x2 (+6 dB),
•power supply: single 6F22 battery,
•current draw: ~5,5 mA @ 9V,
•battery life:
◦~100 h (average cheap battery),
◦up to 200 h (lithium battery),
•works with rechargable USB batteries.

BILL OF MATERIALS
Count Part on PCB
1 9 R1, R2, R3, R4, R5, R6, R7, R8, R9 0,6 W, metal film, 1%
2 1 R10 0,6 W, metal film, 1%
3 100 kA 5 LVLI1, LVLI2, LVLI3, LVLI4, LVLO
4 4 C1, C2, C3, C4
5 1 C5
6 TL072 1 IC1
7 BAT43 1 D1
8 LED 1 LED 3 mm, red
9 5 I 1, I 2, I 3, I 4, OUT
10 1 IC1 standard
11 1 PWR
12 1 +V (RED), -V
13 Male spacer 4 - 8 mm, M3
14 4 -
15 8 - 6 mm, M3
16 Top cover 1 -
17 1 -
18 PCB 1 -
Part value Description
Resistors
47 kΩ
4,7 kΩ
Potentiometers
Alpha Taiwan RV09AF-40-20K-A100K
Capacitors
10 μF tantalum, 25 V
100 nF ceramic, 50 V
Semiconductors
opamp, DIL8
Schottky diode
Mechanical
Jack socket Lumberg 1503-08
DIL8 socket
Slide switch Canal Electronic TS-6S-QH
Battery connector Keystone 84-8
Female spacer 8 mm (+thread length 6 mm), M3
Screw
custom
Bottom cover custom
custom

Step I : solder nine 47 kΩ resistors (R1..R9). Step II : solder one 4,7 kΩ resistor (R10).
Step III : solder one Schottky diode (D1).
Mind the polarity! Black strip should be pointing top!
Step IV : solder one 100 nF ceramic capacitor (C5).

Step V : solder DIL8 socket (IC1).
The small notch in socket should be pointing to the left!
Step VI : bend legs of four 10 μF capacitors (C1..C4) and solder
them (see photo).
Mind the polarity! On tantalum capacitor positive (longer) lead is
marked and it should be pointing to the left!
Step VII : solder five jack connectors (IN1..IN4, UT). Step VIII : solder power switch (PWR) and slide it to the right.

Step IX : solder LED (LED) slightly (~1 mm) above resistors.
Mind the polarity! Cut edge (shorter lead) of the LED should be
pointing to the top!
Step X : solder five potentiometers (LVL1..LVL4, LVL ).
Step XI : cut the battery connector to around 85 mm, strip both
ends of the wires and solder them (red to V+).
Step XII : inspection – double check all the joints. They should
be nice and shiny. If you have isopropyl alcohol, clean them.

Step XIII : insert the battery, remove protection form acrylic
cover and connect it with screws and spacers using fingers.
Step XIV : turn the device on – the LED should lit. The chance
you've soldered everything correctly just increased! Turn it off.
Step XV : Slightly bend the IC leads and put it into the socket.
Notch on the IC should match notch on the socket!
Step XVI : Install the top cover.

Step XVII : Congratulations! Your brand new and shiny portable mixer is ready, I hope it looks as good as mine :)

Operation manual
Controls:
•each knob sets the level for the corresponding
input/output (see diagram),
•fully left (anticlockwise) is equal to silence, fully right
(clockwise) to maximum volume level possible.
First run:
•turn mixer OFF,
•turn all I knobs to around 50% (12 o'clock),
•turn OUT knob full anticlockwise (min. level),
•provide signal to I s of choice,
•connect OUT to your favourite piece of equipment,
•turn mixer O ,
•turn OUT knob slowly clockwise to increase output level.
Notes:
•inputs are monophonic and take signal from the tip of the
jack plug (usually left channel),
•output is stereophonic (or rather double mono) and works
only with stereo cable,
•max. amplification of mixer is x2 (+6 dB),
•both inputs and output are AC coupled,
•for fresh battery maximum mixers output is 5,6 Vp-p
and it will drop with supply voltage,
•6 Vp-p can be considered as safe input voltage level
(don't worry if you fry TL072, they are relatively cheap).