Text preview for : Pass-Labs_Aleph-ONO_Rev.0,1,2,3_sm.pdf part of PASSLAB Pass-Labs Aleph-ONO Rev.0,1,2,3 sm . Rare and Ancient Equipment PASSLAB Audio Pass-Labs_Aleph-ONO_Rev.0,1,2,3_sm.pdf
Back to : Pass-Labs_Aleph-ONO_Rev.0 | Home
PASS LABORATORIES
ALEPH ONO SERVICE MANUAL
REV 0, 1, 2, 3 9/30/1997
Product Description
The Aleph Ono starts off with a low noise power supply using a
custom designed, shielded, low noise 60 Watt toroid transformer.
This gives plus and minus 42-volt DC primary supplies. These are
passively filtered with resistors and capacitors. The rails are then
actively regulated down to plus and minus 32 volts with zero
feedback Mosfets, Q9 for the positive rail and Q23 for the negative.
The Mosfets references are filtered zener stacks of four 9.1 volt
zeners. These supplies are then passively filtered again for each
channel. The moving coil stage has it's own separate capacitance
multiplier Q24 that regulates down to 26 Volts for Q14 the MC amp
cascode.
The moving coil stage uses 4 matched very low noise Jfets
(Q 10 - Q13) operated in parallel giving a noise floor of 475 picovolts.
These are operated at about 15 volts on the drain. These devices
operate feedback free and feed a cascode stage (Q14) whose output
is buffered by Q15 unity gain inverter. This signal is then feed to the
main gain and equalization stage.
The main gain stage provides its gain with a dual monolithic JFET
(Q5) biased with a low noise current source (Q16). This differential
pair is cascoded into Q1 and Q2 and feeds a P channel Mosfet and
then Transistor Q6 . Q3 and Q6 are feed to current source Q17. The
reference for Q17 and Q18 is red Led D5 witch sets the voltage
across R53 and R67 at 1 volt after the base emitter drops. This
reading across these two resistors is important for this stage to work
properly.
The equalization is performed using 1-% tolerance metal film
resistors and polypropylene capacitors. C4, C5 and C6 along with R8
and R9 provide the Riaa equalization curve in the feedback loop. R28
and C8 provide the high frequency EQ and roll off.
Balanced negative out is provided by a unity gain inverter. Q21 and
Q22 differential pair feed Q8 and Q19 N channel Mosfets.
Q25 and Q26 are used to power the mute relays. The front panel
LED must function for Q25 to turn on and pull the mute relays off.
The differences between revisions are generally minor in nature. In
rev 1 muting relays were added to the output. More gain settings
were added in rev 2, along with a physical layout change. An extra
loading resistor was added to the moving magnet input in rev 3.
ALEPH ONO SPECIFICATIONS
Gain 40 dB @ 1 KHz (MM)
71 dB @ 1 KHz (MC)
76 dB @ 1 KHz (MC)
RIAA response plus/minus .1 dB 20-20 KHz
Distortion < .05 % THD @ 20 volts
balanced @ 1 KHz
Maximum Output 20 volts rms.
Output Impedance 150/150 ohms
Input Impedance 47 Kohm 0-650 pF (MM)
5 ohm - 47 Kohm (MC)
Unweighted Noise -90 dB ref. 10 mV input (MM)
-81 dB ref. 1 mV input (MC)
Power consumption 20 watts
Dimensions 19 " W x 11.5 " D x 4 " H
Weight 35 lbs.
PASS
Pass Laboratories
PO Box 219
24449 Foresthill Rd.
Foresthill CA 95631
tel (916) 367 3690
fax (916) 367 2193
web site: www.passlabs.com
A B C D E F G H
30 Volt regulator
1 + 40 Volts
1
R44
Q9
R30 5.1
610 221 2.2K
C23 C24
R29 +
1KUF 1KUF
D2
D1
D1 1N4004 * 4
C21
1KUF D2
C7 C22 .25 AMP SLOW 240 AC
R2
10UF 1KUF .5 AMP SLOW 120 AC
D4
D3
5.1 D3 9.1V
-
T1 F1
C32 S1 P1
D4 C31
1KUF 1KUF 30 VAC VAL
S2 P2
4007
R71 5.1 - 40 Volts S1 P1
- 30 Volt regulator ACJACK
30 VAC
R73 S2 P2
Q23 R72 2.2K
2 + 30 VOLTS - 30 VOLTS
9610 221
2
R75 C12 CL60
1.5K 1KUF C30 C33 D9 TH1
C29
MC SUB REGULATOR R6 1KUF 10UF
1KUF D8
Q24 10K Q3
ZTX450 9610 D7
R42 R4
C34
3.3K 4.02K R12
3300UF R51 V+ D6 9.1V
R76 26 VOLTS 4.75K C10
A 221
10K TO MM STAGE Q2
CB3 Q1
C19 10UF R3 Q6
.047 2SC1844 2SC1844
220UF 2SA991
GAIN SELECT 8.2K C3 Q7
D
SHORT FOR -4 dB R80 100PF R26
G Q15 R17 R23 610
1K 2SK170 10K 22K C11 221
R41
R66 S 10PF
R81
499 4.02k
1K
MOVING MAGNET ADJUST R25P FOR
J1 C4 C6
C16 R49
330PF
R50 INPUT Q5 .01UF .033UF
R28
.35 VOLTS
C35 100K 56 33
3 3300UF
R18
R40 GAIN
S1:1
2SK389
D D
R25P R25 3
499 CB4 SHORT R1 2.21K 5K C7
R7 R8 R9 R28 R82
10K .047 G G
FOR 1 1 1 1 1 1 1
+
6 5 4 3 2 1 0 9 100 7.32K 88.7K 150 +OUT 150
221 R21 10UF
C37 - 10 dB S S
R20 100
R16 Q14 220UF
47K C41 R27
10K 2SC1844 C1 220UF 33
+
+
1 2 3 4 5 6 7 8 220UF C2 R14
C5
A 100K
C13 C14 C15 CX MM MC .047UF .0027
100 220 330 R79
RX
15 VOLTS 1K R52 9610 C8
.01
R5
MOVING COIL INPUT 6.8K
221
Q10 D
Q11 D
Q12 D
Q13 D R22 R55 R54 Q18
J2 Q16 Q17
G G G G 2SC1844
2SC1844 221 221 221
2SK170 S 2SK170 S 2SK170 S 2SK170 S
C29 R67
1 VOLT C27 R53
100PF R31 475 D5 C28 1 VOLT
150
47K 220UF RED 4.7UF
4 R45 R46 R47 R48 BALANCED OUT 4
-30 VOLTS
22 22 22 22
NC1 K1:B
R70 C1 MUTE
S2:2 C20 J3
5.1 2 J4
NO1
1KUF + VAL
8 1 RELAY
R39 10 RCA OUT 1
G XLRO
R38 24R9
7 2
MOVING COIL PREAMP + 30 dB 3 - NC2 K1:C
6 3 C2
R37 47R5 NO2
R36 100 5 4 R57 R11 Q8 VAL
R12
8 1 221 R56 4.75K
R35 249 221 610
9.1V
475 7 2
R34
6 3
R61
R33 825 Q20
Q4 R24 R65
5 4 221
R32 1K 9110 R68 ZTX450 221 47
4.75K C9
C39 R62 R13 -OUT
Q21 22K 332
.001 10UF Installed rev 3 boards starting sn 8029
9110 R15
R61 R63 C38 +OUT C? 1.5K UNREG 40V
100K
RIGHT CHANNEL SHOWN R69
Q21 221 22K 10UF
Q19 680PF
R78
221 610 Q25
5 9110
R60
3.32K
9610
5
LEFT CHANNEL DESIGNATORS USE REFERENCE DESIGNATOR FOLLOWED BY LETTER A 221 D?
R74
R64
R59 D11 K1:A
47 +
475 +
- -
D10
Q26
C39 .01PP ECO 10-8-97 R77