Simple Hybrid Amp

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Published in issue 356, July 2006

Resistors

R1 = 1M

R2,R4 = 180

R3 = 2k2

R5 = 1k

R6,R7 = 100k

R8, R9 = 4k7

R10 = 47k

R11,R12,R13 = 1.5 5W

P1,P2 = 4k7 preset

Capacitors

C1 = 100nF 250V MKT, lead pitch 15mm, dim. 7x18 mm max.

C2 = 220pF

C3 = 10µF 400V radial, lead pitch 5 mm o 13mm max.

C4 = 2µF2 250V, lead pitch 27.5 mm, dim. 11x30 mm max.

C5,C10 = 100nF

C6 = 100µF 25V radial

C7 = 2µF2, lead pitch 5 or 7.5mm

C8,C9 = 4700µF 25V radial, lead pitch 7.5mm, o 18mm max.

Inductors

L1 = ≥ 50 mH, not on board, see text

Semiconductors

D1,D2 = 1N4001

T1 = BC337

T2 = BUZ11 (or IRFZ34N)

Miscellaneous

V1 = ECC88 with 9-pin valve socket (Chelmer Valve Company)

Heatsink for T2, ≤1 K/W

PCB, ref. 050153-1 from The PCBShop