Description
Parasound HCA-1000A 2-Channel Power Amplifier Model: HCA-1000A Price: $445.99 + $54.99 flat-rate ground shipping to US mainland states only Description:Refurbished/Serviced -- See NOTES below for services performedTested after service and working very wellCosmetic condition is exactly as seen in pictures -- some minor marks and scratches due to use and ageAn electronic copy of the users manual will be emailed to the buyer after completion of purchase, if requestedAll work performed by the techs at MC Mobile, Thousand Oaks, CAFeel free to ask questions before purchase, and keep in mind that this amp will be quite different than an unserviced amp of this model. This amp is ready again for prime time. NOTES: These are very nice sounding amps, but almost 30 years old. All of them we have seen need servced even if they are working due to their age and other issues. These amps have complimentary JFET input stages, and good, authentic, P-channel JFETs are now hard to find. Hence, these amps should be serviced before a failure that willl cause the JFETs to fail. 1. Replaced failed, 10A, rectifier bridge with heavier duty 25A bridge2, Replaced 3 blown internal fuses3. Replaced numerous failing caps with high ESR4. Cleaned level controls and swtiches5. Corrected factory mistake in the current overload indicator circuit causing erronious illumination (see NOTE 1 below)6. Set bias so that there is no visible notch distortion at 20 KHz on our scope7. Checked output stage current balance8. Measured power output at 1 KHz into 8 Ohms, one channel driven, and measured the output power at a healthy 166 W/ch RMS with good top to bottom symmetry9. Measured frequency response from 100 Hz to 10 KHz for both channels, and found the response to be very flat with a slight increase at 10 kHz10. Checked short circuit protection and DC protection circuits11. Checked bridging (mono) function -- See NOTE 2 below NOTE 1 : We modify their circuits, so that this amp works in this fashion. If there is a short circuit at the ouput, the protection relay trips out, and the current overload LED illuminates for the appropriate channel. If there is high DC at the output, the protection relay trips out, and the red standby LED illiminates. There is a provision from the factory, that was internally defeated on this amp, to have both the current overload and standby LEDs illuminate for high DC at the output. We thought this was more confusing, so we left it as decribed above. We changed the current overload protection LEDs to also indicate clipping. If this amp is driven into clip, the overload LEDs will illuminate faintly and become brigher as the clipping worsens. Hence, if the current overload LEDs light, the amp is being driven too hard or there is a short. The protection relay will not trip if this amps clips. This is different than what the user manual states; this is just a bonus in this amp. NOTE 2 : This amp can be bridged to mono, and the bridging works. We replaced the supply caps to the op amps that handle this function, so all is well. However, we are not a fan of the bridging for multiple reasons. The amps sound better when used as stereo amps, so it is best to buy a monoblock amp if one wants more single channel clean power.Also, folks get into trouble with hookups and impedance in bridged mode. Some Original Specifications: Continuous Power Output - Stereo: 125 watts RMS x 2, 20 Hz - 20 kHz, 8 ?, both channels driven; 200 watts RMS x 2, 20 Hz - 20 kHz, 4 ?, both channels drivenContinuous Power Output - Mono: 400 watts RMS, 20 Hz - 20 kHz, 8 ?Current Capacity: 45 amperes peak per channelSlew Rate:>130 V/?secondPower Bandwith: 5 Hz - 100 kHz, +0/-3 dB at 1 wattTotal Harmonic Distortion: < 0.03% at full power; < 0.01 % typical levelsIM Distortion: < 0.03 %TIM: unmeasurableDynamic Headroom: > 1.5 dBInterchannel Crosstalk: > 80 dB at 1 kHz; > 60 dB at 20 kHzInput Sensitivity: 1 V for 28.28 V, THX Reference Level; 1.1 V for full outputInput Impedance: 33 k ?S/N Ratio: > 116 dB, full power; > 96 dB, THX Reference LevelDamping Factor: > 800 at 20 HzPower Consumption: 500 wattsDimensions: w 17 1/4 x h 3 1/2 x d 13 1/4, h 4 1/8 with feetNet Weight: 22 lb
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