QSC-USA400-pwr-sm维修电路原理图.pdf

USA 400 FEATURES he USA 400, a member of QSCs world-wide best-selling line of amplifiers, is now even bet- ter. The USA Series now offers even more value and performance: Neutrik Combo input connec- tors (1/4” and XLR), selectable limiters, vari- able low-frequency filters, and even more power in a new rugged, all-steel chassis. Other standard features include comprehensive am- plifier and load protection, ample heat sinks, clip indicators, mono-bridging switch, and ac- tive balanced inputs. The USA 400 is ideal for live sound specialists, system installers, and other professionals who demand QSCs legend- ary reliability and audio quality. QSC Audio Productsthe leader in amplifier technology. USA Series 250 watts per channel at 2 ohms 200 watts per channel at 4 ohms Built-in limiting (defeatable) for speaker protection Selectable high-pass filter (30 Hz, 50 Hz, or out) Active balanced inputs Neutrik ”Combo“ input connectors accommodate both 1/4” TRS and XLR Barrier strip inputs ”Touch-proof“ binding post outputs Passive cooling LED clip indicators Patented Output Averaging short circuit protection Stereo, bridged mono, or parallel operation QSC reliability and audio performance Made in USA 3-year warranty PLUS optional 3-year extended warranty LOAD20Hz-20kHz, 0.1% THD (typical)1kHz, 1% THD (typical) Stereo (W/Ch) 8110 watts125 watts 4200 watts 2250 watts Mono-Bridged 16220 watts250 watts 8400 watts 1675 MacArthur Boulevard Costa Mesa, California 92626-1468 USA Phone: 714/754-6175 Fax: 714/754-6174 RadioFans.CN 收音机爱 好者资料库 ARCHITECTS AND ENGINEERS SPECIFICATIONS The power amplifier shall contain all solid-state circuitry, using complementary silicon semiconductors. The amplifier shall operate from 50-60 Hz AC power, with voltages of 100, 120, or 240 Vac. The amplifier shall operate from a normal household AC outlet, drawing less than 900 VA when driven with random program material at 1/8 rated power into four ohm loads. The amplifier shall be supplied with a single molded AC cord having an appropriate AC plug for the intended operating voltage. The amplifier shall contain two independent channels. Each chan- nel shall have independent protective circuitry against open cir- cuit, short circuit, or reactive loads, and the remaining channel shall continue to operate if one channel fails. A muting circuit shall provide three seconds of muting after turn-on, and shall mute within 1/4 second after turn-off or loss of power, to protect the load against turn-on or turn-off thumps. Self resetting ther- mal shutdown shall protect the circuitry against temperatures in excess of 90C, and a front panel resettable circuit breaker or fuse shall protect against AC overloads. Each channel of the amplifier shall have an independently defeatable limiter. Each channel shall also have bypassable high- pass filtering, with independently selectable -3 dB frequencies of 30 Hz or 50Hz. The limiter and high pass filter controls shall be on an 8-position DIP switch on the amplifiers rear panel. Each channel of the amplifier shall typically be capable of meet- ing the following performance criteria, with both channels driven simultaneously, unless otherwise stated: Output power, 8 ohms per channel, 20 Hz-20 kHz, less than 0.1% distortion, at least 110 watts rms per channel. Output power, 4 ohms per channel, 1 kHz, less than 1% distortion, at least 200 watts rms per channel. Frequency response shall be 20 Hz-20 kHz + 0, - 1 dB at 1 watt output. SMPTE IM distortion shall be less than 0.025% at rated power, 8 ohms, and less than 0.05% at rated power, 4 ohms. IHF damping factor shall be at least 200. Signal to noise, below rated output, shall be at least 105 dB (A weighted). Dynamic head- room at 8 ohms shall be at least 2 dB. The voltage gain shall be 29 dB at full gain. The input sensitivity for rated 8 ohm power shall be 1.12 Vrms. Input impedance shall be 20 kilohms bal- anced and unbalanced noninverting, 10 kilohms unbalanced in- verting. Balanced, bridging input circuit shall be standard, and the amplifier shall meet all performance criteria in the balanced or unbalanced mode. The amplifier shall have passive cooling for ultra-quiet operation. Each channel shall have the following controls, indicators, and connectors: Rear mounted gain control calibrated in dB. Clipping indicator, responding proportionally to any distortion in excess of 0.1%. Balanced/unbalanced input jack of the Neutrik Combo (combined 1/4 TRS and XLR). Bal- anced input of the barrier strip screw terminal type. Speaker ter- minals of the touch proof binding post type. In addition, the chassis shall feature a rear mounted mono-bridging switch, front mounted AC switch and circuit breaker or fuse in some export locations, mounting positions on the rear for optional 70 V out- put transformers, and built-in rack mounting ears. The chassis shall mount in a 19 rack, occupying 3 rack spaces (5.25). Chas- sis depth behind the rails shall be 8.5 plus 1 in allowance for the binding posts. Weight shall be 24 Ib. The amplifier shall be the QSC Model USA 400. BACK USA 400 Specifications OUTPUT POWER (per channel, typical) 8 ohms, 20 Hz to 20 kHz, 0.1%THD, 110 watts 8 ohms, 1kHz,1%THD, 125 watts 4 ohms, 1 kHz,1%THD, 200 watts 2 ohms, 1 kHz,1%THD, 250 watts OUTPUT POWER (bridged mono) 16 ohms, 1 kHz,1%THD, 250 watts 8 ohms, 1 kHz,1%THD 400 watts DISTORTION: SMPTE-IM, less than 0.025% FREQUENCY RESPONSE: 20 Hz to 20 kHz, +0/-1 dB, 1 watt DAMPING FACTOR: Greater than 200 DYNAMIC HEADROOM: 2 dB at 8 ohms NOISE: 105 dB below rated output (A weighted) SENSITIVITY: 1.12 Vrms for rated power (8 ohms) VOLTAGE GAIN: 28 (29 dB) INPUT IMPEDANCE: 10K unbalanced, 20K balanced CONTROLS: Front:AC Switch, AC Circuit Breaker Back:Stereo/Bridge Switch/Ch 1 and Ch 2 Gain Knobs 8 Position DIP Switch for Filter & Limiter INDICATORS: PWR-ON:Green LED CLIP:Red LED, 1 per channel CONNECTORS: (each channel) Input:Barrier strip and Neutrik Combo 1/4 TRS and XLR, tip positive Speakers: Touch proof binding posts COOLING: Passive AMPLIFIER PROTECTION: Full short circuit, open circuit, ultrasonic, and RF protection. Stable into reactive or mismatched loads. LOAD PROTECTION: On/off muting and DC-fault protection. OUTPUT CIRCUIT TYPE: Complementary linear outputs. POWER REQUIREMENTS: 100,120, 240 Vac, 50-60 Hz POWER CONSUMPTION: Normal Operation: 4 ohms per channel: less than 4.4 amps, 120 Vac (900 VA) DIMENSIONS: 19.0 (48.3 cm) rack mounting 5.25 (13.3 cm) tall (3 spaces) 9.5 (24.1 cm) deep WEIGHT: 24 Ibs (10.9 kg) net, 28 Ibs (12.7 kg) shipping Output Averaging short circuit protection (US Patent 4,321,554) SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE. 1675 MacArthur Boulevard Costa Mesa, California 92626-1468 USA Phone: 714/754-6175 Fax: 714/754-6174 RadioFans.CN 收音机爱 好者资料库