A and T Labs
K6 Audio Power Amplifier Assembly Manual
2001 A and T Labs Inc.
AMK6a
9
3.1.4 Transistors and ICs
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Part
Type
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Part
Type
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Part
Type
Q1
MPSA06
Q9
MPSA06
IC1
LM334Z
Q2
MPSA06
Q10
MPSA06
IC2
LM334Z
Q3
MPSA56
Q11
MPSA06
IC3
LM339AN
Q4
MPSA56
Q12
MPSA56
IC4
LF411CN
Q5
MPSA56
Q13
MPSA56
IC5 *
LF357N
Q6
MPSA06
Q14
MPSA06
IC6 ** LF357N
Q7
MPSA56
Q15
MPSA56
IC7
LM358
Q8
MPSA06
Q25
VN0610LL
* Parts required for bridging option
** Parts required for differential input
Install the fuse clips and terminal blocks. The amplifier boards are designed to mount
the input jacks, level set potentiometer, and indicator LEDs on either end of the board,
depending on the unit physical configuration. See section 5 and figures 6,7,9, and 10,
and determine your planned configuration. Then mount these components accordingly,
as follows:
1) Depending on which channel you are building, install the RCA input jack and the
level set potentiometer R43 at the appropriate end of the board (back for 3 ½” unit,
right end, with the power components at the back of the board, for the 5 ¼” unit).
2) The clipping and protection indicator LEDs go on the opposite end from the input
jacks of the board (front for the 3 ½” unit), or on the end of wires to be
remoted
(about 8”) on the front panel for the 5 ¼” unit.
If you have populated the bridging option, the board with R73,74 C20,21,22, and IC5
will be the “input” board for the drive signal), with the switch SW1 and LED 3 on the
other. The cathodes of all the LEDs (the direction the arrow in the symbol points) is the
longer lead. For differential input capability, include the 1/4" jacks on the appropriate
ends of the boards, along with the twisted pair shielded cable from the jack to the
center of the board. If you do not need differential input, omit coax #2, the twisted pair,
IC6 and the components associated with it (R41,42,75,76,77, C23-24).
Last, install coax #1 and the relay K1. The temperature sensor, regulators, and thermal
sensing FET will be left off until heat sink installation, and the output transistors (Q16-
23) will be mounted after preliminary testing is completed.
3.1.5 Miscellaneous parts
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Part
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Part
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Part
Fuse clips (4)
LED1
Twisted pair **
Term. Blocks (5)
LED2
Coax #1
