QSC-USA400-pwr-sm 维修电路原理图.pdf

USA 400FEATUREShe USA 400, a member of QSCs world-widebest-selling line of amplifiers, is now even bet-ter. The USA Series now offers even more valueand performance: Neutrik Combo input connec-tors (1/4” and XLR), selectable limiters, vari-able low-frequency filters, and even morepower in a new rugged, all-steel chassis. Otherstandard 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 forlive sound specialists, system installers, andother professionals who demand QSCs legend-ary reliability and audio quality.QSC Audio Productsthe leader inamplifier technology.USA Series250 watts per channel at 2 ohms200 watts per channel at 4 ohmsBuilt-in limiting (defeatable) forspeaker protectionSelectable high-pass filter (30 Hz,50 Hz, or out)Active balanced inputsNeutrik ”Combo“ input connectorsaccommodate both 1/4” TRS andXLRBarrier strip inputs”Touch-proof“ binding post outputsPassive coolingLED clip indicatorsPatented Output Averaging shortcircuit protectionStereo, bridged mono, or paralleloperationQSC reliability and audioperformanceMade in USA3-year warranty PLUS optional3-year extended warrantyLOAD20Hz-20kHz, 0.1% THD (typical)1kHz, 1% THD (typical)Stereo (W/Ch)8110 watts125 watts4200 watts2250 wattsMono-Bridged16220 watts250 watts8400 watts1675 MacArthur BoulevardCosta Mesa, California 92626-1468 USAPhone: 714/754-6175 Fax: 714/754-6174RadioFans.CN 收音机爱 好者资料库ARCHITECTS AND ENGINEERS SPECIFICATIONSThe power amplifier shall contain all solid-state circuitry, usingcomplementary silicon semiconductors. The amplifier shalloperate from 50-60 Hz AC power, with voltages of 100, 120, or240 Vac. The amplifier shall operate from a normal householdAC outlet, drawing less than 900 VA when driven with randomprogram material at 1/8 rated power into four ohm loads. Theamplifier shall be supplied with a single molded AC cord havingan 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 channelshall continue to operate if one channel fails. A muting circuitshall provide three seconds of muting after turn-on, and shallmute within 1/4 second after turn-off or loss of power, to protectthe load against turn-on or turn-off thumps. Self resetting ther-mal shutdown shall protect the circuitry against temperatures inexcess of 90C, and a front panel resettable circuit breaker orfuse shall protect against AC overloads.Each channel of the amplifier shall have an independentlydefeatable limiter. Each channel shall also have bypassable high-pass filtering, with independently selectable -3 dB frequenciesof 30 Hz or 50Hz. The limiter and high pass filter controls shall beon 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 drivensimultaneously, unless otherwise stated: Output power, 8 ohmsper channel, 20 Hz-20 kHz, less than 0.1% distortion, at least110 watts rms per channel. Output power, 4 ohms per channel, 1kHz, less than 1% distortion, at least 200 watts rms per channel.Frequency response shall be 20 Hz-20 kHz + 0, - 1 dB at 1 wattoutput. SMPTE IM distortion shall be less than 0.025% at ratedpower, 8 ohms, and less than 0.05% at rated power, 4 ohms. IHFdamping factor shall be at least 200. Signal to noise, below ratedoutput, shall be at least 105 dB (A weighted). Dynamic head-room at 8 ohms shall be at least 2 dB. The voltage gain shall be29 dB at full gain. The input sensitivity for rated 8 ohm powershall 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, andthe amplifier shall meet all performance criteria in the balancedor unbalanced mode. The amplifier shall have passive coolingfor ultra-quiet operation. Each channel shall have the followingcontrols, indicators, and connectors: Rear mounted gain controlcalibrated in dB. Clipping indicator, responding proportionally toany distortion in excess of 0.1%. Balanced/unbalanced inputjack 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, thechassis shall feature a rear mounted mono-bridging switch, frontmounted AC switch and circuit breaker or fuse in some exportlocations, mounting positions on the rear for optional 70 V out-put transformers, and built-in rack mounting ears. The chassisshall 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 forthe binding posts. Weight shall be 24 Ib. The amplifier shall bethe QSC Model USA 400.BACKUSA 400 SpecificationsOUTPUT POWER (per channel, typical)8 ohms, 20 Hz to 20 kHz, 0.1%THD, 110 watts8 ohms, 1kHz,1%THD, 125 watts4 ohms, 1 kHz,1%THD, 200 watts2 ohms, 1 kHz,1%THD, 250 wattsOUTPUT POWER (bridged mono)16 ohms, 1 kHz,1%THD, 250 watts8 ohms, 1 kHz,1%THD 400 wattsDISTORTION:SMPTE-IM, less than 0.025%FREQUENCY RESPONSE:20 Hz to 20 kHz, +0/-1 dB, 1 wattDAMPING FACTOR:Greater than 200DYNAMIC HEADROOM: 2 dB at 8 ohmsNOISE: 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 balancedCONTROLS:Front:AC Switch, AC Circuit BreakerBack:Stereo/Bridge Switch/Ch 1 and Ch 2 Gain Knobs8 Position DIP Switch for Filter & LimiterINDICATORS:PWR-ON:Green LEDCLIP:Red LED, 1 per channelCONNECTORS: (each channel)Input:Barrier strip and Neutrik Combo 1/4 TRS and XLR, tip positiveSpeakers: Touch proof binding postsCOOLING: PassiveAMPLIFIER PROTECTION:Full short circuit, open circuit, ultrasonic, and RF protection. Stable into reactive or mismatchedloads.LOAD PROTECTION:On/off muting and DC-fault protection.OUTPUT CIRCUIT TYPE:Complementary linear outputs.POWER REQUIREMENTS: 100,120, 240 Vac, 50-60 HzPOWER CONSUMPTION:Normal Operation: 4 ohms per channel: less than 4.4 amps, 120 Vac (900 VA)DIMENSIONS:19.0 (48.3 cm) rack mounting5.25 (13.3 cm) tall (3 spaces)9.5 (24.1 cm) deepWEIGHT: 24 Ibs (10.9 kg) net, 28 Ibs (12.7 kg) shippingOutput Averaging short circuit protection (US Patent 4,321,554)SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.1675 MacArthur BoulevardCosta Mesa, California 92626-1468 USAPhone: 714/754-6175 Fax: 714/754-6174RadioFans.CN 收音机爱 好者资料库