YORKVILLE ap4020 ys4020 Owner'S Manual Download

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INTRODUCTION

Your new

Yorkville

AP4020/4040 power amplifier is designed and built to provide years of trouble free performance. The

AP4020/4040 combines the field proven reliability of our Audiopro amplifiers with customer requested features such as switch-

able limiters, a Mono/Stereo/Bridge switch, and SPEAKON™ output connectors as well as binding posts.
The AP4020/4040 weighs a comfortable but solid 42 pounds, fits into two rack spaces, and reproduces music with over 4000

Watts of headroom. It will drive reactive phase shifted loads with no difficulty - even though it is fully protected from accidental

short circuits. Our design goal was to create an amplifier which would do exactly what an amplifier should do: reproduce music

with great power, complete reliability, and uncompromising signal fidelity. We think you will agree that the

Yorkville

AP4020/4040 does exactly that.

INPUTS

Balanced Inputs

Either XLR or two–circuit ‘Ring, Tip, Sleeve’ Stereo 1/4”

PHONE cords may be used. Each channel’s XLR input is inter-

nally paralleled with its phone input (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.

Unbalanced Inputs

Ordinary single circuit Standard

1/4” PHONE plugs may be used to

connect unbalanced signals. IMPOR-

TANT NOTE: Such plugs effectively

connect the ring terminal to sleeve

ground, so they work correctly.

However, if you use a Stereo 1/4”

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

AP4020/4040 . Connect a balanced cable to the

AP4020/4040 just as you would if you were running a bal-

anced 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 AP4020/4040 ’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 AP4020/4040.

Driving Multiple AP4020/4040’s

In large installations it is often desirable to operate many

amplifiers in tandem. Since each channel’s XLR input is inter-

nally paralleled with its phone input, you may use the remain-

ing input jack as an output to the

next amplifier. Obviously you will

need both XLR to XLR and PHONE

to PHONE patch cords if you are

going to tandem more than two

amplifiers.

NOTE: These patch cords MUST
be balanced whether the input
signal is balanced or unbalanced!

GROUND SWITCH

Switching the ground switch on

the rear panel will disconnect chas-

sis ground from circuit ground.

Safety (earth) ground is still connect-

ed to the chassis. We do not recom-

mend lifting the ground strap unless

you are experiencing problems with

ground loop hum in multiple ampli-

fier setups where lifting the ground

straps of all but one a

mplifier cures

the hum problem.

CAUTION: Sometimes hum problems are an indication of improper
AC wiring somewhere else in your system. Don’t just doctor the
symptom by lifting grounds. Fix the cause by making sure that the
proper electrical wiring safety regulations have been adhered to.