Description

Integrated Amplifier /Tube stereo Power Amplifier Esoteric A-100 230v Integrated Amplifier Esoteric A-100. 230v Everything is in perfect condition, no problems. Measurements were made at 120V AC-line voltage with both channels being driven. Measurements made on left channel and into the "RCA 1" input and on the 8-ohm output unless otherwise noted. This integrated amplifier does not polarity. AC line current draw at idle: 1.96A Input sensitivity for 1W output into 8 ohms, volume at maximum, Lch/Rch: 72.0mV/67.8mV Input impedance @ 1kHz RCA 1 input: 10k ohms XLR input: 20k ohms Direct input: >350k ohms Output impedance at 50Hz: 4.7 ohms Gain, output voltage divided by input voltage, volume at maximum, Lch/Rch: 39.3X, 31.99dB/41.7X, 32.4dB Output noise, 8-ohm load, 1k-ohm input termination, Lch/Rch Volume control at reference position wideband: 0.63mV, -70.0dBW/0.68mV, -72.4 dBW A weighted: 0.30mV, -79.5dBW/0.16mV, -85.0dBW Volume control full clockwise wideband: 0.63mV, -70.0dBW/0.65mV, -72.8dBW A weighted:0.28mV, -80.1dBW/0.20mV, -83.0dBW Volume control full counterclockwise wideband: 0.60mV, -73.5dBW/0.76mV, -71.4dBW A weighted: 0.29mV, -79.8dBW/0.32mV, -78.9dBW Power output with 1kHz test signal 8-ohm load at 1% THD: 9.0W 8-ohm load at 10% THD: 56.0W 4-ohm load at 1% THD: 7.4W 4-ohm load at 10% THD: 66.0W Tube stereo power amplifier Esoteric A-100, which is designed as a pure "power amplifier", but with the help of a switch on the rear panel turns into an integrated amplifier - an input selector (RCA x3 / XLR x1) is added to the circuit, as well as a high-quality attenuator - volume control. In the A-100, all amplification stages, except for the final ones on the powerful KT-88, are powered by fully stabilized power supplies. This approach produces an exceptionally deep and finely detailed soundstage. The A-100 delivers at least 45 watts per channel from a push-pull ultra-linear KT-88 output stage driven by a directly coupled cathode follower. The cathode follower and voltage gain stage are also directly coupled to form a triple VBS (variable bias system) controlled by a ZVS (zero voltage control system). A newly designed, custom output transformer, using specially treated copper foil as the secondary winding, provides the best possible inductive coupling to the primary winding and allows for extremely gentle and accurate reproduction of music. All this improves stability and transparency of sound. All the tubes except the KT-88 output tubes are fed with direct current, which dramatically reduces the level of alternating current noise. The power supply and output transformer are firmly fixed in an extremely rigid ‘H-shaped’ design, and the circuit components, organized into separate blocks, are located around it. The A-100 has an extremely low noise level, despite its all-tube design.