paX: a power amplifier with error correction (2)
The voltage amplifier and input buffer stages
Published in issue 377, May 2008
Last month we discussed the principle of error correction and developed an error-correction power output stage. In this installment we will use H.ec in a voltage amplification stage and present the complete amplifier.
Resistors (0.25W metal film) R1-R4,R6,R8,R17,R18 = 47Ω R7 = 220Ω R9,R10,R12,R25,R34 = 4kΩ7 R11 = 249Ω R13 = 2kΩ74 R16 = 5kΩ23 R19,R20,R30,R31 = 2kΩ15 R21-R24,R60 = 100Ω R26,R27,R33,R40-R43,R46,R51 = 1kΩ R28 = 10Ω R29 = 3kΩ0 R32 = 33Ω R35,R36 = 619Ω R37,R38 = 680Ω R39,R45 = 1MΩ R44 = 7kΩ5 R47,R48 = 1kΩ8 2W MF R49,R50 = 10 kΩ R52-R55 = 0Ω22 5W ceramic R64 = 1Ω5 2W R65 = 6(8 2W RV1, RV2 = 200( multiturn trimmer R5,R14,R15,R56-R59, R61-R63 = not present Capacitors C1,C3,C23 = 150pF polypropylene C2, C4,C5,C9,C14-C16,C19,C22, C24,C25 = 100nF cer. C6-C8,C13,C21 = 1µF 63V foil C10 = 220nF 50V cer. C11,C12,C17,C18 = 470µF 63V C26 = 1nF foil Inductors L1 = 5µH (see text) Semiconductors D1, D2, D5,D6,D10,D11 = zener diode 15V 0.5W D3,D4,D9,D12,D13,D14 = 1N4148 D7,D8 = 1N4003 Q1,Q2,Q9 = 2SA1208 Q3,Q4,Q10 = 2SC2910 Q5,Q11,Q17,Q18 = BC546B Q6,Q14,Q19,Q20 = BC556B Q13,Q16 = STD03N (+ isolation pad & mounting hardware) Q12,Q15 = STD03P (+ isolation pad & mounting hardware) U1,U2,U4 = AD844AN U3 = TL051CP Miscellaneous J9 = header 2 x 1 pin (signal input) J10 = header 2 x 3 pin (+ flatcable) 4 IC sockets DIL08 PCB, ref. 071085-1
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