Befaco Quad-T Assembly Manual

This module has four equal parts (four oscillators type twin-T), the drawing of the PCB is intentioned for an easy
assembly procedure by symmetrizing two groups of oscillators taking the central axis by normal, and themselves
symmetric around the line at 45º and 135º respectively. On this way once you find one component in one of the parts is
easy to find his simile on the other tree portions. Finally in the middle we can find a transistor amplifier who can
saturate the audio signal, on this way we can produce natural percussive sounds (avoiding saturation) or a more
aggressive sounds by increase the level of the sum at the amplifier input.
Part list:
Resistors:
Cant. Value
8 2K2 Red, red, red gold
4 2M Red, black, gren, gold
1 3K3 Orange, orange, red, gold
4 6K8 Blue, gray, red, gold
4 10K Brown, black, orange, gold
4 22K Red, red, orange, gold
5 47K Yellow, purple, orange, gold
12 100K Brown, black, yellow, gold
1 110K Brown, brown, black, orange, brown R33
4 270K Red, purple, yellow, gold
1 470K Yellow, purple, yellow, gold
Pots:
4 5K
4 200K ó 100K 204 ó 104 white or black
Condensers:
Cant. Value
1 560pF n56 or 561
4 1uF 1uF
2 2,2uF 2.2uF
4 10nF 103
12 330nF 330n
The ones labeled as: C1, C2, C3 - C13, C14, C15 - C20, C21, C22 - C32, C33, C34 (rounded by a white box) are the
determinant of the tune of each sound, we will put here a PIN in order to choose the tune of them.
Actives:
9 BC546A Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9 – transistor, put them according to the drawing on PCB
1 LED3MM D1 - LED diode, check polarity, long leg = +
Quad-T assembly manual:
Code
502 blue
Code
R3, R11, R50, R55, R8, R21, R40, R53
R9, R19, R42, R52
R30
R1, R22, R38, R60
R6, R10, R51, R58
R14, R18, R43, R48
R13, R29, R31, R32, R49
R5, R7, R15, R17, R24, R25, R36, R37, R45, R46, R54, R56
R2, R12, R47, R59
R28
R16, R23, R39, R44 – multi-turn potentiometer
R20, R26, R34, R41 – 1 turn potentiometer
C4
C7, C8, C27, C28 (electrolytic check polarity before
C17, C18 solder it, long leg = + )
C6, C10, C25, C29
C5, C9, C11, C16, C19, C24, C26, C30
Name on PCB
Name on PCB