December 2004

Classé Audio Delta CA-2200 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 with both channels driven using the unbalanced inputs.
• Gain, unbalanced input/balanced input: 28.6x, 29.1dB/28.6x, 29.1dB.
• Output noise, 8-ohm load, unbalanced input, 1k-ohm input termination: wideband 0.282mV, -80.0dBW; A weighted 0.068mV, -92.4dBW.
• Output noise, 8-ohm load, balanced input, 600-ohm input termination: wideband 0.285mV, -79.9dBW; A weighted 0.065mV, -92.8dBW.
• AC line current draw at idle: 1.44A.
• Output impedance at 50Hz: 0.0055 ohms.
• This amplifier does not invert polarity.

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 224W
  
  
• 4-ohm load at 1% THD: 425W

General

The Classé Audio CA-2200 is a medium-/high-power solid-state design with typically wide bandwidth and very low output impedance.

Chart 1 shows the frequency response of the amp with varying loads. As can be seen, the output impedance, as judged by the closeness of spacing between the curves of open circuit, 8-ohm, and 4-ohm loading, is quite low. The variation with the NHT dummy load in the audio range is negligible.

Chart 2 illustrates how total harmonic distortion plus noise versus power varies for 1kHz and 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. Amount of rise in distortion at high frequencies is fairly pronounced and is similar to that of many amplifiers measured.

Damping factor versus frequency is shown in Chart 4 and is unusually high.

A spectrum of the harmonic distortion and noise residue is plotted in Chart 5. The magnitude of the AC-line harmonics is low and typical of many of the amplifiers measured at BHK Labs. The test signal harmonics are both even and odd harmonic, with the odd harmonics dominating the total harmonic sum. The higher-order harmonics quickly decline into the noise level.

Red line: open circuit
Magenta line: 8-ohm load
Blue line: 4-ohm load
Cyan line: NHT dummy-speaker load

(line up at 20W 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

4-ohm output loading
Cyan line: 350W
Blue line: 100W
Magenta line: 20W
Red line: 2W

Damping factor = output impedance divided into 8

1kHz signal at 10W into a 4-ohm load

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