Monday, January 22, 2018


All amplifier measurements are performed independently by BHK Labs. All measurement data and graphical information displayed below are the property of the SoundStage! Network and Schneider Publishing Inc. Reproduction in any format is not permitted.

Notes: All measurements were made at 120V AC line voltage, both channels driven -- and, unless otherwise noted, through the Direct (DIR) balanced input.

Power output

  • Power output at 1% THD+N: 595.0W @ 8 ohms, 988.0W @ 4 ohms
  • Power output at 10% THD+N: 777.0W @ 8 ohms, 1324.0W @ 4 ohms

Additional data

  • Input/output polarity: noninverting
  • AC-line current draw
    • Idle: 125W, 1.52A, 0.67PF
    • Standby: 4.0W, 0.06A, 0.52PF
  • Gain: output voltage divided by input voltage, 8-ohm load
    • BAL input: 18.21X, 25.2dB
    • RCA input: 18.23X, 25.2dB
    • DIR input: 3.996X, 12.0dB
  • Input sensitivity for 1W output into 8 ohms
    • BAL input: 155.3mV
    • RCA input: 155.2mV
    • DIR input:  707.8mV
  • Output impedance @ 50Hz: 0.014 ohm
  • Input impedance @ 1kHz
    • BAL input: 792k ohms
    • RCA input: 534k ohms
    • DIR input: 78.6k ohms
  • Output noise, 8-ohm load, BAL input terminated with 600 ohms
    • Wideband: 193.2uV, -83.3dBW
    • A weighted: 72.8uV, -91.8dBW
  • Output noise, 8-ohm load, RCA input terminated with 1k ohms
    • Wideband: 208.1uV, -82.7dBW
    • A weighted: 74.8uV, -91.6dBW
  • Output noise, 8-ohm load, DIR input terminated with 600 ohms
    • Wideband: 124.8uV, -87.1dBW
    • A weighted: 67.4uV, -92.5dBW

Measurements summary

The Taurus Mono is a high-powered amplifier in Constellation Audio’s new Revelation Series of models. All Constellation power amps use a unique circuit design comprising MOSFET and JFET devices. The power-output stage uses only N-type devices, driven symmetrically.

Chart 1 shows the frequency response for both the Direct (DIR) and Balanced (BAL) inputs. Since the response deviation for open circuit, 8 ohms, and 4 ohms were virtual overlays, due to the Taurus Mono’s low output impedance, these curves are for an 8-ohm loading.

Chart 2A illustrates how, in DIR mode, the Taurus Mono’s total harmonic distortion plus noise (THD+N) vs. power varies for 1kHz and SMPTE IM test signals and amplifier output load for loads of 8 and 4 ohms. Chart 2B shows the results for BAL mode.

The DIR input’s THD+N as a function of frequency at several different power levels is plotted in Chart 3. The rise in distortion at high frequencies is fairly pronounced.

The Taurus Mono’s damping factor vs. frequency, shown in Chart 4, is relatively high, remaining at 2-3kHz before declining with increasing frequency.

Chart 5 plots the spectrum of harmonic distortion and noise residue of a 10W, 1kHz test signal. The magnitude of the AC-line harmonics is relatively complex and the signal harmonics are dominantly the third harmonic -- a mark of the symmetry of the plus and minus half-cycles of the signal.

Chart 1 - Frequency response of output voltage as a function of output loading

Chart 1

Red line = DIR input
Magenta line = BAL input

Chart 2 - Distortion as a function of power output and output loading

Chart 2A - DIR input

Chart 2A

(Line up at 100W to determine lines)
Top line = 4-ohm SMPTE IM distortion
Second line = 8-ohm SMPTE IM distortion
Third line = 4-ohm THD+N
Bottom line = 8-ohm THD+N

Chart 2B - BAL input

Chart 2B

(Line up at 20W to determine lines)
Top line = 4-ohm SMPTE IM distortion
Second line = 4-ohm THD+N
Third line = 8-ohm SMPTE IM distortion
Bottom line = 8-ohm THD+N

Chart 3 - Distortion as a function of power output and frequency

Chart 3

(8-ohm loading)
Red line = 1W
Magenta line = 10W
Blue line = 30W
Green line = 100W
Yellow line = 400W

Chart 4 - Damping factor as a function of frequency

Chart 4

Damping factor = output impedance divided into 8

Chart 5 - Distortion and noise spectrum

Chart 5

1kHz signal at 10W into an 8-ohm load

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