Modes
The AP6020 can be configured for Bridge, dual-MONOor STEREO operation via the rear panel MODE switch. The following is a descrip- tion 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.
Stereo Mode
•Two independent amplifiers, Amp A and Amp B.
•Two loads are driven.
•Loads are connected between the BLACK and RED posts on each channel.
Bridge Mode
•Channel A&B inputs are paralleled. GAIN B has no effect.
•Output signals are equal in amplitude but opposite in phase.
•One load is driven.
•The load is connected between the two RED binding posts. The BLACK posts are not used.
Subsonic Filter Switch
The AP6020 features a specially designed subsonic filter that effective- ly blocks potentially destructive energy in the band below 40 Hz. The filter provides a 12 dB/octave. skirt below 40 Hz. It is implemented with a two-pole network designed to minimize phase shift down to 40 Hz. We recommend using this filter in conjunction with some subwoofers and with all high power full range cabinets. With the filter disabled, the AP6020 is flat down to 20-Hz, and rolls off at 12dB/Oct below that.
Limiter Switch
With the internal limiters activated, the AP6020’s gain is continu- ously adjusted to fit the signal within the available dynamic range. Occasional clipping is permitted. The limiters will not only help to protect your system’s horns and tweeters, but will automatically make the best use of the available dynamic headroom. With the limiters activated, all you need to do is turn up the signal level until you start to see some clipping. The limiters will make sure that you are getting the maximum clean power output at all times. Setting the switch to the IN position completely disables both limiters.
Protect LED
In the event of a shorted load or a load which is of too low an imped- ance for the amplifier to handle the PROTECT LED will flash alternate- ly on and off at about 3 second intervals. The sound may come on and off at ½ second intervals. In this case, the fault is in the speakers or the speaker cables and should be located and remedied. No reset of the AP6020 is required to restore proper operation. The PROTECT LED will stay on if the amplifier has overheated. Check the speaker load impedance and any restrictions to air flow at the air intake or exhaust vents of the amplifier.
Short Circuit Protection
The AP6020 is fully protected against all possible passive load con- ditions. It can operate into a dead short continuously without dam- age. (However, we don’t recommend that you short your AP6020 “just for fun.” Shorts do create a lot of stress on the output devices). The output stage uses a unique triple slope VI-limitingscheme which is sophisticated enough to remain inert during transient currents in excess of 150 Amperes and phase angles of more than 45 degrees. It is capable of protecting the output stage from damage due to acciden- tal short circuits and improper loads.
DC Protection
In the unlikely event of the AP6020’s outputs going DC, a thyristor circuit will short the output terminals and divert all potentially harmful currents away from your speakers.
Thermal Protection
In the unlikely event that the AP6020 overheats, the signal will be sporadically cut off and the PROTECT LED will stay on. The AP6020 is designed and tested to operate under “worst case” conditions with- out shutting down, so if you experience a thermal shut down you should check for blocked air flow.
Cooling
The fan draws air in from the front and expels hot air through the rear vents. This is compatible with most installations. Since hot air rises, the heated air forcibly expelled from the back tends to rise away from the equipment rack. This draws cool air from the floor upwards into the front of the rack. In some cases where the rear of the rack is obstructed, it may be necessary to install rack fans to aid cooling. If there are no obstructions, no secondary cooling is required.
Clip LEDs
The CLIP LEDS on the front panel will visibly indicate any signal excursion beyond the dynamic headroom of the amplifier.
Reliability
The AP6020 is designed and manufactured by Yorkville Sound. Each unit undergoes a thorough, temperature cycled burn-in period, and each circuit is tested by both manual and sophisticated computer controlled equipment which is capable of identifying any deviation from the design center parameters. The design of the AP6020 is con- servative with respect to the power handling capabilities of the output devices. The topology guarantees that thermal stress not secondary breakdown will set the limits of operation, while the computer opti- mized heat dissipation system insures that excessive thermal stress will not occur. Yorkville’s reputation as a manufacturer of reliable equip- ment will be further enhanced by the AP6020.
The AP6020 is not only suitable for use in both heavy duty tour- ing sound reinforcement systems but also when high headroom and low distortion are needed to fully reproduce the dynamic range and clarity of today’s CD recordings. It is built to survive grueling road conditions and constant 2-Ohm operation. Its reliability in a fixed installation running 4 or 8-ohm studio monitors is without parallel.
Fan Filter Maintenance
The AP6020 is factory equipped with fan filters mounted on the air- intake grills located on the amplifier’s front panel. Regular cleaning of this filter will increase the amplifier’s long term reliability. The filters should be removed and washed at the first sign of visible clogging. This will typically occur every four to six weeks depending on use and environment. Replacement filters are inexpensive and can be ordered
