Improved Hybrid HeadPhone Amplifier
Materials
Gerber file
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Extra info / Update
Specifications
Voltages measured w.r.t. circuit ground
T1/T6 base 0.7 V
T2/T7 base 1.4 V
T3/T8 base 3.8 V
T3/T8 Emitter 2.8 V
ECC82 grid 4 V
T10/T12 Emitter 6.2 V
T9/T11Base 0.67 V
ECC82 anodes 10 V
ECC82 pin 5 9.4 V
D2 (across device) 0.8 V
T5 VCE 1.3 V
R6/R14 (across device) 6.85 V
Component list
R1,R8,R9,R15 = 10k?
R2,R4,R10,R12 = 91k? (E96: 90k?9)
R3,R11 = 15k?
R5,R13 = 22?
R6,R14,R16,R17,R22,R23 = 1k?
R7 = 39k?
R18,R21,R24,R27 = 560?
R19,R25 = 33k?
R20,R26 = 8k?06
Capacitors
C1,C6 = 2?F2 100V, lead pitch 22.5mm (WxL = 10 x 26 mm abs. max.)
C10,C12 = 10?F 63V, lead pitch 22.5mm (WxL = 10 x 26 mm abs. max.)
C2,C7 = 100nF, MKT, lead pitch 5mm or 7.5mm
C3,C8,C11,C13 = 100?F 25V, lead pitch 2.5mm, diam. 8.5 mm max.
C4,C9 = 2200?F 25V, lead pitch 7.5mm, diam. 18mm max.
C5 = 1000 ?F 25V, lead pitch 5mm, diam. 10 mm max.
Semiconductors
D1,D3 = red LED
D2 = 1N4004
T1,T2,T6,T7,T9,T10,T11,T12 = BC550C
T3,T5,T8 = BC517
T4 = BD139
Miscellaneous
V1 = ECC82 or 12AU7
9-pin (‘Noval’) PCB mount socket, e.g. Conrad Electronics # 120529
PCB, # 080310-1 from www.thepcbshop.com
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