QSC-USA400-pwr-sm维修电路原理图.pdf

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1、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

2、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

3、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 in

4、puts 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 Mad

5、e 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-

6、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 sha

7、ll 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 c

8、ontain 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 sh

9、all 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 overl

10、oads. 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 am

11、plifiers 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 chan

12、nel. 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 damp

13、ing 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

14、 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 c

15、hannel 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

16、 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

17、- 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 Specif

18、ications 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 th

19、an 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 CONTR

20、OLS: 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: Tou

21、ch 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,

22、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