Anthem PVA 2
Stereo Amplifier: Measurements
All amplifier measurements are performed
independently by BHK Labs. Please click to learn
more about how we test amplifiers there. All measurement data and graphical
information displayed below are the property of SoundStage! and Schneider
Publishing Inc. Reproduction in any format is not permitted.
- Measurements were made with 120V AC line voltage.
- Power output and distortion plotted with both channels
- Gain: 28.0x, 28.9dB.
- Output noise, 8-ohm load, unbalanced input, 1k-ohm input
termination: wideband 0.115mV, -87.8dBW; A weighted 0.028mV, -100.1dBW.
- AC line current draw at idle: 0.41A.
- Output impedance at 50Hz: 0.02 ohms.
- This amplifier does not invert polarity.
Power output with 1kHz test signal
- 8-ohm load at 1% THD: 119W
- 4-ohm load at 1% THD: 193W
The Anthem PVA 2 is a solid-state design with low measured
distortion, wide frequency response, and very low output impedance
Chart 1 shows the frequency response of the amp with
varying loads. As can be seen, this unit has low output impedance as evidenced by the v
ery close spacing of the curves for an open circuit down to 4-ohm loading in the audio
range. The deviation above the audio range is common and typical due to the usual presence
of a series RL network in the output for circuit stability and the decrease in overall
negative feedback with increasing frequency. When an amplifier has such low output
impedance, it doesn't make any sense to measure the NHT dummy speaker load as we do for
many amplifiers because its impedance variation won't show on the chart. Needless to say,
the frequency-response variation with varying-impedance speaker loads with this amp will
be negligible. Chart 2 illustrates how total harmonic distortion plus noise versus power
varies for a 1kHz sine wave, SMPTE IM test signals, and amplifier output load. As can be
seen, attainable power is greater for the 4-ohm load, as is usual for most power
amplifiers. Total harmonic distortion plus noise as a function of frequency at several
different power levels is plotted in Chart 3. Distortion up to about 300Hz is very low,
but as is typical with most power amplifiers, it does rise as frequency increases. Damping
factor versus frequency is shown in Chart 4 and is very high for this design. A spectrum
of the harmonic distortion and noise residue is plotted in Chart 5 for a 10W 1kHz signal
into a 4-ohm load. Amount of the signal distortion products is very low, as is the amount
of AC line-hum harmonics. Virtually absent is the cluster of AC line harmonics around some
of the signal harmonics as has been seen in some other amplifiers measured.
- Frequency Response of Output Voltage as a Function of Output Loading
Red line: open circuit
Magenta line: 8-ohm load
Blue line: 4-ohm load
|Chart 2 - Distortion as a Function
of Power Output and Output Loading
(line up at 50W to determine lines)
Top line: 4-ohm SMPTE IM
Second line: 8-ohm SMPTE IM
Third line: 4-ohm THD+N
Bottom line: 8-ohm THD+N
|Chart 3 - Distortion
as a Function of Power Output and Frequency
8-ohm output loading
Red line: 1W
Magenta line: 10W
Blue line: 30W
Cyan line: 100W
|Chart 4 - Damping Factor
as a Function of Frequency
Damping factor = output impedance divided into 8
|Chart 5 - Distortion and
1kHz signal at 10W into an 4-ohm load