Yorkville Sound AP1020 manual Subsonic Filter Switch, Limiter Switch, Protect LED, DC Protection

Stereo Mode

•Channels A and B inputs are separate.

•Two independent amplifi- ers, Amp A and Amp B.

•Two loads are driven.

•Loads are connected

between the black and red posts on each channel.

Bridge Mode

•Channels A and B inputs are paralleled. Gain B has no effect.

•Output signals are equal in amplitude but oppo- site 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 AP1020 features a specially designed sub- sonic filter, which effectively 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 net- work 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 fil- ter disabled, the AP1020 is flat down to 6 Hz, and rolls off at 12 dB/octave below that.

Limiter Switch

When the internal limiters are activated, the AP1020’s gain is continuously self- adjusted to fit the signal within the avail- able dynamic range. Occasional clipping is permitted. The limiters will not only help to protect your system’s mid-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 Out posi- tion completely disables both limiters.

Protect LED

In the event of a shorted load, or a load which is of too low an impedance for the amplifier to handle ,the Protect LED will flash alternately in about 7-second intervals. The sound may come on and off at ½-second. In this case, the fault is in the speakers or the speaker cables and should be located and remedied. No reset of the AP1020 is required to restore proper operation. The Protect LED will stay on if the amplifier has overheated. Check the speaker load impedance, the position of the load select switch, and any restric- tions to air flow at the air intake or exhaust vents of the amplifier.

Short-Circuit Protection

The AP1020 is fully protected against all possible passive load conditions. It can operate with a dead short continuously without damage. We don’t recommend that you short your AP1020 “just for fun,” short-circuits create a lot of stress on the output devices. The output stage uses a unique triple-slope VL limiting scheme

that is sophisticated enough to remain inert during transient cur- rents in excess of 40 Amperes and phase angles of more than 45 degrees, yet is capable of protecting the output stage from damage due to accidental short circuits and improper loads.

DC Protection

In the unlikely event of the AP1020’s outputs “going DC,” a thy- ristor circuit will short the output terminals and divert all poten- tially harmful currents away from your speakers.

Thermal Protection

In the unlikely event that the AP1020 overheats, the signal will be sporadically cut off and the Protect LED will stay on. If further heating occurs, due to a malfunction, the internal thermal breaker will interrupt the primary circuit. There is no visible indication of this rare condition. The AP1020 is designed and tested to operate under “worst case” conditions without shutting down, check for blocked airflow if you experience a thermal shutdown.

Cooling

The fan draws air inward from the front and expels hot air through the rear vents on the amplifier. This is compatible with other Yorkville power amplifiers (and 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 fans in the rack to aid cooling. If there are no obstructions, secondary cooling is not required.

Fan Filter Maintenance

The AP1020 is factory equipped with a fan filter mounted on the air intake grill on the amplifier’s front panel. Regular cleaning of this filter will increase the amplifier’s long-term reliability. The fil- ter should be removed and washed at the first sign of visible clog- ging. This will typically occur every four to six weeks depending on use and environment. Replacement filters are inexpensive and can be ordered through Yorkville dealers. The foam filter should be removed if a regular inspection schedule is not going to be fol- lowed. The amplifier can operate without the filter in place, but the amplifier should be cleaned internally (by a qualified service technician) when dust is visible on the heatsink fins.

Note: In an unusually dusty location removing the foam fil- ter can extend the operating time before thermal shutdown could occur. At that time, the internal heatsinks should be cleaned thoroughly.

CAUTION: The AP1020 can deliver over 800 Watts of power into a bridged load. Yorkville’s own high power speaker systems have circuit-breaker protection built in. Although these speakers will protect themselves, they are unlikely to be damaged by a bridged AP1020. However, many other speaker manufacturers make “high power cabinets” with no protection features at all

Yorkville Sound is not responsible for any damage, which may result as a consequence of exceeding such a speaker’s power handling capability. Yorkville’s two-year unconditional warranty does not cover any consequential damages to non-Yorkvilleequipment. Please consider these facts carefully before you choose to run your AP1020 in bridged mode!