YORKVILLE AP4K YS1112 Owner's Manual

Contents

YORKVILLE AP4K YS1112 Owner's Manual Manual pdf 5 page image

2Mono ModeThis can be achieved by using the remaining jacks to make the parallel connection. (see previous)• 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 SwitchThe AP4K features a specially designed subsonic filter which effectively blocks potentially destructive energy in the bandbelow 50 Hz. The filter provides a 18 dB/octave. skirt below 50 Hz. It is implemented with a three pole network designed tominimize phase shift down to 50 Hz. We recommend using this filter in conjunction with some subwoofers and with all highpower full range cabinets. With the filter disabled, the AP4K is flat down to 20-Hz, and rolls off at 18dB/Oct below that.Limiter SwitchWith the internal limiters activated, the AP4K’s gain is continuously adjusted to fit the signal within the available dynamicrange. Occasional clipping is permitted. The limiters will not only help to protect your system’s horns and tweeters, but willautomatically make the best use of the available dynamic headroom. With the limiters activated, all you need to do is turnup the signal level until you start to see some clipping. The limiters will make sure that you are getting the maximum cleanpower output at all times. Setting the switch to the IN position completely disables both limiters.Protect/Clip LEDWhen the amplifier is in Bridge mode, in the event of a shorted load or a load which is of too low an impedance for the am-plifier to handle the PROTECT/CLIP LED’s will flash alternately on and off at about 3 second intervals. The sound may comeon and off at ½ second intervals. In this case, the fault is in the speakers or the speaker cables and should be located andremedied. No reset of the AP4K is required to restore proper operation. The PROTECT/CLIP LED will stay on if the amplifierhas overheated. Check the speaker load impedance and any restrictions to air flow at the air intake or exhaust vents of theamplifier.2 ohm/4 ohm ModeThe AP4K is equipped with the capability of working in two different modes. If the amplifier is connected to speaker loads of4-ohms or above, the switch on the rear panel can be set to 4-ohm mode. In this mode the amplifier will operate at a highervoltage level and will maximize the available headroom. If you need to drive loads that are less than 4-ohms you can oper-ate the amplifier in the 2-ohm mode. This will reduce the amount of voltage available and allow the amplifier to supply morecurrent without overheating. If you are driving speakers with limited power handling capability, the 2-ohm mode can also beused to reduce the amount of power available to the speakers. (See the power chart)Short Circuit ProtectionThe AP4K is fully protected against all possible passive load conditions. It can operate into a dead short continuously with-out damage. (However, we don’t recommend that you short your AP4K “just for fun.” Shorts do create a lot of stress on theoutput devices). The output stage uses a unique triple slope VI-limiting scheme which is sophisticated enough to remaininert during transient currents in excess of 100 Amperes and phase angles of more than 45 degrees, yet is capable of pro-tecting the output stage from damage due to accidental short circuits and improper loads.DC ProtectionIn the unlikely event of the AP4K’s outputs going DC, a thyristor circuit will short the output terminals and divert all poten-tially harmful currents away from your speakers.Thermal ProtectionWhen the amplifier is operating in the 4-ohm mode and an overheating condition exists, the amplifier will automaticallyswitch itself to the 2-ohm mode. This could happen as a result of the speaker impedance being less than 4-ohms, the ambi-ent temperature being too high or the airflo w being restricted. This function will allow the amplifier to continue to produceoutput even in adverse conditions. In the unlikely event that the AP4K overheats, the signal will be sporadically cut off andthe PROTECT/CLIP LED will stay on. The AP4K is designed and tested to operate under “worst case” conditions withoutshutting down, so if you experience a thermal shut down you should check for blocked air flow.