YORKVILLE AP2020 Owner's Manual

Also see for AP2020: Service manual Service manual Owner's manual

Contents

Stereo Mode• Channel A and B inputs are separate.• Two independent amplifiers, Amp A and Amp B.• Two loads are driven.• Loads are connected between the BLACK and RED postson each channel.Bridge Mode• Channel A and 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 bindingposts. The BLACK posts are not used.Subsonic Filter SwitchThe AP2020 features a specially designed subsonic filter,which effectively blocks potentially destructive energy in theband below 40 Hz. The filter provides a 12 dB/octave. Skirtbelow 40 Hz. It is implemented with a two-pole networkdesigned to minimize phase shift down to 40 Hz. We recom-mend using this filter in conjunction with some subwoofersand with all high power full range cabinets. With the filterdisabled, the AP2020 is flat down to 20 Hz, and rolls off at12dB/Oct below that.Limiter SwitchWith the internal limiters activated, the AP2020’s gain is con-tinuously adjusted to fit the signal within the available dynamicrange. Occasional clipping is permitted. The limiters will notonly help to protect your system’s horns and tweeters, but willautomatically make the best use of the available dynamic head-room. With the limiters activated, all you need to do is turn upthe signal level until you start to see some clipping. The limiterswill make sure that you are getting the maximum clean poweroutput at all times. Setting the switch to the IN position com-pletely disables both limiters.Protect LEDIn the event of a shorted load or a load which is of too lowan impedance for the amplifier to handle the PROTECT LEDwill flash alternately on and off at about 3 second intervals.The sound may come on and off at ½ second intervals. In thiscase, the fault is in the speakers or the speaker cables andshould be located and remedied. No reset of the AP2020 isrequired to restore proper operation. The PROTECT LED willstay on if the amplifier has overheated. Check the speakerload impedance and any restrictions to air flow at the airintake or exhaust vents of the amplifier.Short Circuit ProtectionThe AP2020 is fully protected against all possible passive loadconditions. It can operate into a dead short continuously with-out damage. (However, we don’t recommend that you shortyour AP2020 “just for fun.” Shorts do create a lot of stresson the output devices). The output stage uses a unique tripleslope VI-limiting scheme, which is sophisticated enough toremain inert during transient currents in excess of 50 Amperesand phase angles of more than 45 degrees, yet is capable ofprotecting the output stage from damage due to accidentalshort circuits and improper loads.DC ProtectionIn the unlikely event of the AP2020’s outputs going DC, athyristor circuit will short the output terminals and divert allpotentially harmful currents away from your speakers.Thermal ProtectionIn the unlikely event that the AP2020 overheats, the signal willbe sporadically cut off and the PROTECT LED will stay on. Iffurther heating occurs, due to some malfunction, an internalthermal breaker will interrupt the primary circuit. There isno visible indication of this rare condition. The AP2020 isdesigned and tested to operate under “worst case” conditionswithout shutting down, so if you experience a thermal shutdown you should check for blocked air flow.CoolingThe fan draws air in from the front and expels hot air throughthe rear vents. This is compatible with most installations.Since hot air rises, the heated air forcibly expelled from theback tends to rise away from the equipment rack. This drawscool air from the floor upwards into the front of the rack. Insome cases where the rear of the rack is obstructed, it maybe necessary to install rack fans to aid cooling. If there are noobstructions, no secondary cooling is required.Fan Filter MaintenanceThe AP2020 is factory equipped with a fan filter mountedon the air-intake grill located on the amplifier’s front panel.Regular cleaning of this filter will increase the amplifier’slong-term reliability. The filter should be removed and washedat the first sign of visible clogging. This will typically occurevery four to six weeks depending on use and environment.Replacement filters are inexpensive and can be orderedthrough Yorkville dealers. The foam filter should be removedif a regular inspection schedule is not going to be followed.The amplifier can operate without the filter in place, but aqualified service technician should clean the amplifier inter-nally when dust is visible on the heatsink fins.Note: In an unusually dusty location, without regular filterinspections, removing the foam filter can extend the operat-ing time before thermal shutdown could occur. At that time,the internal heatsinks should be cleaned thoroughlyClip LEDsThe CLIP LEDs on the front panel will visibly indicate any sig-nal excursion beyond the dynamic headroom of the amplifier.ReliabilityThe AP2020 is designed and manufactured by YorkvilleSound. Each unit undergoes a thorough, temperature cycledburn-in period, and each circuit is tested by both manual andsophisticated computer controlled equipment which is capableof identifying any deviation from the design center parameters.The design of the AP2020 is conservative with respect to thepower handling capabilities of the output devices. The topol-ogy guarantees that thermal stress not secondary breakdownwill set the limits of operation, while the computer optimizedheat dissipation system insures that excessive thermal stress willnot occur. Yorkville’s reputation as a manufacturer of reliableequipment will be further enhanced by the AP2020.CAUTION: The AP2020 can deliver over 2100 Watts of power into a bridged load. Yorkville’s own high power speaker systemshave circuit-breaker protection built in. These speakers will protect themselves and thus are unlikely to be damaged by a bridgedAP2020. However, many other speaker manufacturers make “high power cabinets” with no protection features at all. YorkvilleSound is not responsible for any damage, which may result as a consequence of exceeding such a speaker’s power handling capa-bility. Yorkville’s Two Year Unconditional Warranty does not cover any consequential damages to non-Yorkville equipment. Pleaseconsider these facts carefully before you choose to run your AP2020 in Bridge Mode!