Yorkville Sound AP2020 Introduction, Balanced Inputs, Unbalanced Inputs, Remote Referencing

Introduction

Your new Yorkville AP2020 power amplifier is designed and built to provide years of trouble free performance. The AP2020 combines the field proven reliability of our Audiopro amplifiers with customer requested features such as switchable limiters, a Mono/Stereo/Bridge switch, and SPEAKON™ output connectors as well as binding posts.

The AP2020 weighs a comfortable but solid 35 pounds, fits into two rack spaces, and reproduces music with over 2000 Watts of headroom. It will drive reactive phase shifted loads with no difficulty - even though it is fully protected from acciden- tal 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 AP2020 does exactly that.

Inputs

Balanced Inputs

Either XLR or two–circuit ‘Ring, Tip, Sleeve’ Stereo ¼-inch 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 ¼-inch PHONE plugs may be used to connect unbalanced signals.IMPORTANT NOTE: Such plugs effectively connect the ring terminal to sleeve ground, so they work correctly. However, if you use a Stereo ¼-inch PHONE plug on an unbalanced line, you MUST short the Ring terminal to the sleeve terminal, otherwise the sensitivity will be

6 dB 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 AP2020. Connect a balanced cable to the AP2020 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 modi- fied end into your unbalanced piece of equipment. This con- nection enables the AP2020’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 AP2020.

Driving Multiple AP2020’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 chassis ground from circuit ground. Safety (earth) ground is still connected to the chassis. We do not recommend lifting the ground strap unless you are experiencing problems with ground loop hum in multiple amplifier setups where lifting the ground straps of all but one amplifier 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 regula- tions have been adhered to.

Modes

The AP2020 can be configured for dual-MONO, STEREO, or BRIDGED MONO operation via this rear panel MODE switch. The following is a description of each mode:

Mono Mode

•Channel A & B inputs are paralleled.

•Each gain control adjusts the signal level for its respective channel

•Output signals are of equal phase.

•Two loads are driven.

•Loads are connected between the BLACK and RED post on each channel.