QUAD II Power Amplifier
R |
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8 |
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10 |
6 |
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9 |
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C |
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2 |
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3 |
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6 |
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HT and |
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V1 |
115V |
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EF86 |
1.2mA |
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heaters to |
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110V 0.22mA |
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Control unit |
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socket |
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R5 |
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h h |
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R2 |
h h |
180kΩ |
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SK |
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1MΩ |
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1 |
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R4 |
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6 |
5 |
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4 |
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2.2V |
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3 |
C1 |
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680Ω |
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2 |
1 |
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0.1µ F |
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R3 |
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Input |
1MΩ |
h h |
R6 |
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180kΩ |
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110V |
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0.22mA |
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V2 |
115V |
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R1 |
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EF86 |
1.2mA |
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1.5MΩ |
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R10 100Ω
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330V |
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17mA |
C2 |
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L1 |
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14mA |
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0.1µ F |
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350V |
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V3 65mA |
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KT66 |
R7 |
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680kΩ |
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h h |
R8 |
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26V |
2.7kΩ |
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R9 |
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h h |
680kΩ |
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V4 |
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KT66 |
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65mA |
C3 |
C4 |
R12 |
0.1µ F |
16µ F |
180Ω |
350V |
450V |
3W |
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V5 |
310V |
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rms |
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340V |
GZ32 |
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147mA |
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310V |
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rms |
For 15 Ω |
speakers link S to |
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R as shown, for 8 |
Ω link S |
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to T and Q toR |
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T1 |
T |
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Y |
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Z |
S |
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U |
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VR
W Q
X
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SK2 |
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Output |
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SK3 |
C5 |
C6 |
25µ F |
16µ F |
50V |
450V |
5V rms
h
6.3V rms
h
E
C 6 and C |
4 are in the |
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large square can. C |
6 |
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is marked +P (for |
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plain foil) and has |
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the higher ripple |
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rating, C |
4 is marked |
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+E (for etched foil) and is more like a standard electrolytic capacitor
T2
HT
240V or 130V
HT |
220V or 115V |
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200V or 100V |
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5V |
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5V |
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com |
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6.3V |
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6.3V |
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F1 |
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2A 200-250V |
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3A 100-130V |
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PL1 |
a.c. mains from QUAD 22 |
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control unit |
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Note: The original capacitors for C |
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and C 3 had insulated metal bodies which were connected to ground, the small capacitance to ground controls
the open loop frequency response and
thus the stability with feedback; change these capacitors with caution!
R11 470Ω
QUAD II Power Amplifier Schematic Drawing 11175 iss.1 Redrawn in original style by Keith Snook d.c.~daylight ltd. 1994
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