Preamplifier 2012 (3)

Part 3: level indicator, source selector, power supply

Published in issue 6/2012 on page 20

This month we close off the discussions of the individual boards that make up the preamplifier, both in terms of theory of operation and construction: LLLL board, PSU board, input board, and PSU board.

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Products

Components

LLLL board (# 110650-6)
Resistors
(0.25W, 1%)
R1,R2,R3,R5,R11,R12,R13,R15 = 20kOhm
R4,R6,R7,R14,R16,R17 = 10kOhm
R8,R9,R18,R19 = 1kOhm
R10,R20 = 100kOhm
R21 = 910Ohm
R22,R23,R25 = 22kOhm
R24 = 100Ohm
R26,R27 = 220Ohm
Capacitors
C1-C4 = 2.2μF 20% 100V, diam. 6.3mm, 2.5mm pitch
C5-C9 = 100nF 10% 100V, 7.5mm pitch
C10,C11= 100µF 20% 25V, diam. 6.3mm, 2.5mm pitch
C12,C13 = 220nF 10%, 100V, 7.5mm pitch
Inductors
L1,L2 = 1mH 3.6Ohm 370mA, axial
Semiconductors
D1-D14 = 1N4148
T1 = BC557B
IC1-IC4 = NE5532
IC5 = LM339
Miscellaneous
K1-K4,K6 = 2-pin pinheader, 0.1’’ pitch (2.54mm)
Socket headers for K1-K4,K6
K5 = 3-pin pinheader, 0.1’’ pitch (2.54mm)
Socket header for K5
K7 = 3-way PCB terminal block, 5mm pitch
RE1,RE2 = V23105-A5003-A201, 12V/960Ohm, 230V/3A, DPDT
PCB # 110650-6

 

Input board (# 110650-3)
Resistors
R1,R2 = 0Ohm
Capacitors
C1-C4 = 220nF 10% 100V, 7.5mm lead pitch
Miscellaneous
K1,K3,K5,K7 = XLR socket, PCB mount, horizontal, 3-way
K11 = XLR plug, PCB mount, horizontal, 3-way
K2,K4,K6,K8-K10,K12 = RCA/Phono socket, PCB mount, Pro Signal type PSG01545 (red) ® or PSG01546 (white) (L)
K13,JP1-JP4 = 2-pin pinheader, 0.1’’ pitch (2.54mm)
Socket header for K13
K14,K15,K16 = 4-pin pinheader, 0.1’’ pitch (2.54mm)
Socket headers for K14,K15,K16
K17 = 10-way boxheader, straight, 0.1’’ pitch (2.54mm)
S1-S4 = 3-pin pinheader, 0.1’’ pitch (2.54mm)
Jumpers for S1-S4,JP1-JP4
RE1-RE4 = V23105-A5003-A201, 12V/960Ohm, 230V/3A, DPDT
PCB # 110650-3; 2 pcs required

Front panel board (# 110650-4)
Resistors
(0.25W, 1%)
R1 = 220Ohm
R2 = 3.3kOhm
Semiconductors
D1 = LED, green, 3mm, through hole
D2 = LED, red, 3mm, through hole
Miscellaneous
K1 = 10-way boxheader, straight, 0.1’’ pitch (2.54mm)
K2,K5,D1,S1-S3 = 2-pin pinheader, 0.1’’ pitch (2.54mm)
Socket headers for K2,K5,D1,S1-S3
K3,K4 = 3-pin pinheader, 0.1’’ pitch (2.54mm)
Socket headers for K3,K4
K6 = 2-way PCB terminal block, 5mm pitch
S1,S2,S3 = switch, SPDT (On-On)
S4,S5 = 2-pole, 6-position rotary switch, PCB mount, e.g. Lorlin type CK1050
PCB # 110650-4

Power supply board (# 110650-5)
Resistors
(0.25W, 1%)
R1,R3 = 100Ohm
R2,R4 = 1.3kOhm
R5 = 1Ohm
R6,R7 = 12kOhm
Capacitors
C1,C3,C7,C9,C11,C13 = 100nF 10% 100V, 7.5mm pitch
C2,C4 = 100µF 20% 25V, 6.3mm diam., 2.5 mm pitch
C5,C6, = 47µF 20%, 25V, 6.3 mm diam., 2.5 mm pitch
C8,C10 = 4700µF 20% 35V, 22mm diam., 10mm pitch
C12 = 10µF 20% 63V, 6.3mm diam., 2.5mm pitch
C14-C17 = 47nF 50V, ceramic, 5mm pitch
Semiconductors
D1,D2 = 1N4004
D3-D6 = MBR1045
D7 = LED, red, 3mm, through hole
D8 = LED, green, 3mm, through hole
IC1 = LM317
IC2 = LM337
IC3 = 7815
Miscellaneous
K1,K2,K3 = 3-way PCB terminal block, 5mm pitch
K4,K5,K6 = 2-way PCB terminal block, 5mm pitch
HS1,HS2 = heatsink, 50.8 mm, Fischer Elektronik type SK 129 50,8 STS
HS3 = heatsink, 50.8 mm, Fischer Elektronik type SK 104 50,8 STS
PCB # 110650-5 (www.elektorpcbservice.com)
Not on PCB:
Tr1 = AC power transformer, 115/230V primary, 2x18V/50VA secondary, e.g. Multicomp # MCTA050/18, Farnell (Newark) # 9530380
F1 (230VAC) = fuse, 0.315A antisurge, 5x20mm, panel mount
F1 (115VAC) = fuse, 0.63A antisurge, 5x20mm, panel mount
S1 = 115/230V AC line voltage selector, e.g. Arcolectric Switches type T22205BAAC
S2 = AC power switch