POWER AMPLIFIER XS350 XS250 Owner’s Manual 350 POWER POWER AMPLIFIER XS SERIES ON OFF POWER SIGNAL CLIP CH A PROTECTION CLIP SIGNAL CH B E
Introduction Thank you for purchasing a Yamaha XS350, XS250 series power amplifier. This series of audio amps was developed from Yamaha's wealth of experience in building PA equipment and its tradition of careful attention to every detail of circuit design. These amps feature high power and superb quality together with superior reliability and stability, guaranteeing the highest possible audio performance.
Precautions • • • • • • • • • Connect this unit’s power cord only to an AC outlet of the type stated in this Owner’s Manual or as marked on the unit. Failure to do so is a fire and electrical shock hazard. Do not allow water to enter this unit or allow the unit to become wet. Fire or electrical shock may result. Do not place heavy objects, including this unit, on top of the power cord. A damaged power cord is a fire and electrical shock hazard.
Controls and Functions ■ Front Panel POWER 1 3 2 ON 4 OFF POWER SIGNAL CLIP CH A 1 POWER switch and indicator This is the main POWER switch. Press to power ON the amplifier. Press again to power OFF. The POWER indicator lights up when the amplifier is powered ON. 2 SIGNAL indicators These green LED indicators light up when the respective channel’s output signal exceeds 2 Vrms. This is equivalent to 1/2 W into 8Ω, 1 W into 4Ω.
■ Rear Panel 1 2 3 4 FILTER CHANNEL B CHANNEL A FREQ. FREQ.
4 SPEAKERS terminals 6 GND terminals Two types of speaker output terminals: Binding post (Channel A-1, B-1) and barrier strip (Channel A-2, B-2) are available. These parallel wirings are internally connected and output identical signals simultaneously. The output impedance varies depending on whether you use either or both types of SPEAKERS terminals. (Refer to “Speaker Impedance” on page 7 for more information.) The following figures show terminal polarity in STEREO, PARALLEL, and BRIDGE modes.
■ Speaker Impedance In STEREO and PARALLEL modes, the minimum load (i.e., speaker) impedance is 4Ω. In BRIDGE mode it is 8Ω. Make sure that the impedance does not fall below this specified impedance. Using the barrier strip and binding posts simultanuously STEREO mode connections: MODE SPEAKERS BRIDGE STEREO PARALLEL + – + – + + – – Set to STEREO PARALLEL mode connections: MODE BRIDGE STEREO PARALLEL – + + – – + + – Set to PARALLEL Each speaker min.
Using the barrier strip or terminal posts STEREO mode connections: MODE BRIDGE STEREO PARALLEL Set to STEREO PARALLEL mode connections: MODE BRIDGE STEREO PARALLEL Set to PARALLEL • Using the barrier strip • Using the terminal posts SPEAKERS SPEAKERS + – + – + + – – Not used – + + – – + + + – – Not used + – – + Each speaker min. 4Ω + – Each speaker min.
Caution for Speaker Connection 1. Turn off the POWER switch. 2. Remove the cover attachment screws and remove the protective cover from the speaker terminals. Screw 3. For Barrier strip: After removing approx. 15 mm of insulation from the ends of the speaker cables, bind the bare ends of the speaker wires in the corresponding speaker terminals and tighten the terminals to securely clamp the wires. Refer to page 6 for speaker porality.
Rack Mounting ■ Mounting in an EIA standard rack If multiple high-power amp units are mounted in a rack with poor ventilation, the heat from the amps will cause the interior of the amp to become very hot, causing the performance of the amps to be impaired. In particular, when mounting in a rack whose back can not be left open, mount according to the following instructions. Rack: Leave a gap of 10 cm or more between the rear panel of the rack and the rear panel of the amplifier. Fan: Use a fan with 1.
■ Portable Rack Mounting This unit uses a forced cooling system in which air comes in through the front opening and goes out from the sides and rear. If you mount a single unit on a portable rack, be sure to maintain vent openings on the rear and sides.
Specifications ■ General Specifications XS250 Power Output Level (Rated Power) 20 Hz~20 kHz THD+N= 0.1% XS350 8Ω/STEREO 4Ω/STEREO 8Ω/BRIDGE 170 W + 170 W 250 W + 250 W 500 W 230 W + 230 W 350 W + 350 W 700 W 1 kHz THD+N= 0.1% 8Ω/STEREO 4Ω/STEREO 8Ω/BRIDGE 185 W + 185 W 280 W + 280 W 560 W 250 W + 250 W 400 W + 400 W 800 W 1 kHz, 20 ms, no clip 600 W + 600 W 2Ω/STEREO 400 W + 400 W Power Bandwidth Half Power 10 Hz~40 kHz (THD+N= 0.
■ Block Diagram HPF CHANNEL A (BRIDGE) (PARALLEL) CLIP FREQ INPUT CHANNEL A (BRIDGE) (PARALLEL) SIGNAL – A-1 BA LPF CHANNEL A + + – + PROTECTION + – LOW CUT SUB WOOFER OFF – G Protector INV INPUT CHANNEL B-1 SPEAKERS + HPF – G INPUT CHANNEL B – FREQ CHANNEL B A-2 LPF + + – + CHANNEL B-2 BA CHANNEL B LOW CUT SUB WOOFER OFF PARALLEL BRIDGE STEREO – CLIP SIGNAL MODE D:319 ■ Dimensions H:132 W:480 Unit: mm 13
Troubleshooting The following table lists the main causes of abnormal operation and the corrective measures required, as well as the protective circuit operation in each case. Indicator Probable Cause Remedy There is a short at a speaker terminal, amplifier terminal, or wire. Locate and correst the cause of the short. The amplifier load is excessive. Use a speaker system with an impedance of at least 4Ω (stereo) or 8Ω (bridge). The heat sink temperature has exceeded 90°C.
YAMAHA CORPORATION V352950 R1 1 IP 16 NP Printed in Taiwan Pro Audio Division, #18/3 P.O.
