1
Introduction
Your new Yorkville Audiopro AP4K power amplifier is designed and built to provide years of trouble free performance. The
AP4K combines the field proven reliability of our Audiopro amplifiers with customer requested features such as switchable
limiters, a Stereo/Bridge switch, SPEAKON™ output connectors and binding posts.
The AP4K weighs a comfortable 42 pounds, fits into two rack spaces and reproduces music with over 7000 Watts of
headroom. It will drive reactive phase shifted loads with no difficulty - it is fully protected from accidental short circuits. Our
design goal was to build an amplifier to do exactly what an amplifier should do, reproduce music with great power, complete
reliability with uncompromising signal fidelity. We believe that the Yorkville AP4K does exactly that.
Inputs
Either XLR or four–circuit ‘Ring, Tip, Sleeve’ Stereo 1/4-inch PHONE cords may be used. Each channel’s XLR input is in-
ternally paralleled with its phone inputs (The TIP of the channel ‘A’ PHONE input is connected to pin 2 of its XLR input, the
RING is connected to pin 3, and the Sleeve is connected to PIN 1). PIN 2 is in phase, PIN 3 is 180 degrees out of phase,
and PIN 1 is ground. We recommend using balanced lines for the best hum -free performance, particularly when chaining
multiple amplifiers.
Using Unbalanced 1/4-inch Cables
Ordinary single circuit Standard 1/4-inch PHONE plugs may be used to connect 1/4-inch cables with unbalanced signals.
IMPORTANT NOTE:
Such plugs effectively connect the ring terminal to sleeve ground, so they work correctly. However, if you
use a Stereo 1/4-inch PHONE plug on an unbalanced line, you MUST short the Ring terminal to the sleeve terminal, otherwise
the sensitivity will be 6dB lower than is specified! (The same applies to the XLR input: To connect an unbalanced source via the
XLR input, you must connect the signal to Pin 2 and ground BOTH Pin 1 and Pin 3).
Remote Referencing
You can approach balanced performance with unbalanced sources by utilizing the remote reference feature of the AP4K .
Connect a balanced cable to the AP4K just as you would if you were running a balanced line. At the other end, connect Pin
3 and Pin 1 together, (or connect ring to sleeve if you are using a PHONE plug cable), and plug this modified end into your
unbalanced piece of equipment. This connection enables the AP4K ’s input to look down the cable directly at the output jack
of the unbalanced equipment. Any hum voltage generated across the cable’s impedance will be attenuated by the common
mode rejection of the AP4K.
Driving Multiple AP4K’s
In large installations it is often desirable to operate many amplifiers in tandem. Since each channel’s XLR input is internally
paralleled with its phone inputs, you may use the remaining input jack as an output to the next amplifier. You can use either
XLR or PHONE jacks to make these connections.
NOTE:
These patch cords MUST be balanced whether the input signal is balanced or unbalanced.
Bridge
Mode
HP Filter
Limiter
Clip
Power
Limit
0
dB
-6
-40
A
B
Stereo
Bridge
Active
Defeat
Defeat
50 Hz
-51
-1
-21
-3
-12
-4
-9
-6
- 00
0
dB
-51
-1
-21
-3
-12
-4
-9
-6
- 00
0
dB
Power
Circuit Breaker
4K
PROFES SION A L POWER A MPLIFIER
A
B
A
B
Min. Speaker Impedance
SPEAKER OUTPUTS
W
ARNING: SHOCK HAZARD • DO NOT OPEN
A
VIS: RISQUE DE CHOC • NE P
AS OUVRIR
DESIGNED & MANUFACTURED BY
YORKVILLE SOUND • TORONTO, CANADA
www.yorkville.com
1800 WATTS PER CHANNEL
2 or 4-OHMS MIN
(selectable)
BRIDGE
Bridge Input
PARALLEL
PARALLEL
WARNING: RISK OF HAZARDOUS ENERGY! SEE OPERATING MANUAL.
AVERTISSEMENT: ÉNERGIE ÉLECTRIQUE DANGEREUSE! VOIR LE CAHIER D'INSTRUCTION.
*
SPECIAL CABLE REQUIRED
(+1,-1)
(+1,-1)
2-OHM
4-OHM
STEREO
A (
+1,-1)
B (
+2,-2)
BRIDGED
*
+
(
+1)
–
(
+2)
MODEL TYPE: YS1112
A-Z1560 / 1v1
230V
50Hz 5,0A
120VAC
60Hz 10A
AMPLIFIER INPUTS
ALL INPUTS ARE BALANCED
L
O
C
K
L
O
C
K
C
Certified
4K
P R O F E S S IO N A L P O W ER A MP L IFIER
