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.

Measurements were taken at both channels’ Coaxial S/PDIF, Line 2, and Phono inputs, at 120V AC line voltage, both channels driven.

All unless otherwise noted: the volume control was set for 5W output into 8 ohms, for an input level into Line 2 of 500mV; the results discussed below are for the left channel only; and an Audio Precision AUX-0025 external low-pass filter was used for the speaker-output measurements.

Power output

  • Power output at 1% THD+N: 64.1W @ 8 ohms, 76.7W @ 4 ohms
  • Power output at 10% THD+N: 75.0W @ 8 ohms, 82.5W @ 4 ohms

Additional data

  • Input/output polarity (analog and digital): noninverting
  • AC-line current draw
    • Idle: <0.5W
    • Operating: 14.1W, 0.22A, 0.54PF
  • Gain: output voltage divided by input voltage, 8-ohm load, volume at +10dB
    • Speaker output, Line 2 input: 60.2X, 35.6dB
    • Speaker output, Phono input: 3810.0X, 71.6dB
    • Pre/Sub output, Line 2 input: 6.16X, 15.8dB
    • Pre/Sub putput, Phono input: 390.6X, 51.8dB
  • Input sensitivity for 1W output into 8 ohms
    • Line 2 input: 47.0mV
    • Phono input: 0.74mV
  • Output impedance @ 50Hz
    • Speaker output: 0.016 ohm
    • Pre/Sub output: 440 ohms
  • Input impedance @ 1kHz
    • Line 2 input: 18.0k ohms
    • Phono: 44.0k ohms
  • Output noise, speaker output, 8-ohm load, input terminated with 1k ohm, Lch/Rch
    • Without AUX-0025 measurement filter (high-frequency switching)
      • Wideband: 165.2mV / 158.6mV, -24.7dBW / -25.0dBW
    • With AUX-0025 filter, volume at -3.5dB (ref 5W output for 500mV input)
      • Wideband: 486.1uV / 382.1uV, -75.3dBW / -77.4dBW
      • A weighted: 58.4uV / 53.0uV, -93.7dBW / -94.6dBW
    • With AUX-0025 filter, volume at -90dB
      • Wideband: 197.8uV / 175.9uV, -83.1dBW / -84.1dBW
      • A weighted: 32.1uV / 32.2uV, -98.9dBW / -98.9dBW
    • With AUX-0025 filter, volume at +10dB
      • Wideband: 1970.0uV / 1390.0uV, -63.1dBW / -66.2dBW
      • A weighted: 196.5uV / 149.7uV, -83.2dBW / -85.5dBW

Measurements summary

The NAD D 3045 is a feature-laden little integrated amplifier offering digital inputs as well as analog line and phono inputs.

Chart 1 shows the D 3045’s frequency response with varying loads, with and without the Audio Precision AUX-0025 external low-pass filter. The output LC filtering must have been included in the overall feedback loop to produce a response so invariant with load. Most impressive!

Chart 2 illustrates how the D 3045’s total harmonic distortion plus noise (THD+N) vs. power varies for 1kHz and SMPTE intermodulation test signals and amplifier output load for 8- and 4-ohm loads.

The D 3045’s THD+N as a function of frequency at several different power levels is plotted in Chart 3. The amount of increase of distortion with frequency is admirably low, if not absent -- in my career of measuring many amplifiers, this is very rare.

The damping factor vs. frequency of the D 3045 is shown in Chart 4. Like the unchanging THD+N vs. frequency, the damping factor remains high at a much higher frequency than most power amplifiers.

Chart 5 plots the spectrum of the D 3045’s harmonic distortion and noise residue of a 10W, 1kHz test signal. The AC-line harmonics are low and simple, with some 120Hz visible. The signal harmonics are dominated by third-order harmonics, with second- and higher-order harmonics of much lower magnitude.

Chart 6 is a measure of the phono section’s RIAA equalization error. It shows extremely good accuracy.

Chart 7 is the frequency response of the D 3045’s digital input for sample rates of 44.1, 96, and 192kHz. Of interest is the gentle rolloff of the high frequencies for the two higher rates, which implies less ringing of the leading edges of transient signals.

Chart 8 shows the D 3045’s input/output linearity. This is usually done with a bandpass filter, to exclude noise and see only the signal amplitude. It is also instructive to take the same measurement within an audioband bandwidth, as that shows the ultimate noise level when the signal level descends into the noise.

I also looked briefly at the performance of the D 3045’s headphone amplifier. With a 32-ohm load, hard clipping began at about 1.5W, and low distortion below about 1.3W. With a 600-ohm load, clipping began at about 115mW.

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

Chart 1

Red line = with AUX-0025 measuring filter
Magenta line = without AUX-0025 measuring filter
(Note: these responses are representative of 4-, 8-, and open-load curves)

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

Chart 2

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

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

Chart 3

(8-ohm loading)
Cyan line = 1W
Magenta line = 10W
Blue line = 30W
Red line = 60W

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

Chart 6 - Phono RIAA equalization response

Chart 6

Chart 7 - Digital-input frequency response

Chart 7

Red line = 44.1kHz sample rate
Magenta line = 96.0kHz sample rate
Blue line - 192.kHz sample rate

Chart 8 - Digital input-output linearity

Chart 8

Magenta line = with usual bandpass filter
Red line = 10Hz - 20kHz