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Link: reviewed by Dennis Burger on SoundStage! Access on November 1, 2022

General Information

All measurements taken using an Audio Precision APx555 B Series analyzer.

The PMA-1700NE was conditioned for 1 hour at 1/8th full rated power (~9W into 8 ohms) before any measurements were taken. All measurements were taken with both channels driven, using a 120V/20A dedicated circuit, unless otherwise stated.

The PMA-1700NE offers three line-level analog inputs (RCA); one pair of phono inputs (RCA), configurable for moving magnet (MM) or moving coil (MC), fixed line-level outputs (RCA), main-in inputs (RCA), one digital coaxial input (RCA), two digital optical inputs (TosLink), one digital USB input, two separate speaker-level outputs (A and B), and one headphone output over a 1/4″ TRS connector.

For the purposes of these measurements, the following inputs were evaluated: digital coaxial, analog line-level, as well as phono (MM and MC). Unless otherwise stated, Source Direct mode was engaged, which bypasses bass, treble, and balance functions, and Analog 2 Mode was used for the analog measurements, which disables both front panel display and the digital circuits.

Most measurements were made with a 2Vrms line-level at the analog input, 5mVrms at the MM input, 0.5mVrms at the MC input, and 0dBFS at the digital input. The volume control does not have a numerical display. The signal-to-noise ratio (SNR) measurements were made with the same input signal values but with the volume set to achieve the rated output power of 70W (8 ohms). For comparison, on the line-level input, a SNR measurement was also made with the volume at maximum, where only 0.219Vrms was required to achieve 70W into 8 ohms.

Based on the high accuracy and variability of the left/right volume channel matching (see table below), the PMA-1700NE volume control is likely digitally controlled but operates in the analog domain. The PMA-1700NE offers 5-3dB volume steps between the minimum and 8 o’clock position, and 0.5dB steps for the remainder of the volume range. Overall range is -53.1dB to +40.7dB (line-level input, speaker output).

Volume-control accuracy (measured at speaker outputs): left-right channel tracking

Volume position Channel deviation
min 0.108dB
9 o'clock 0.052dB
12 o'clock 0.054dB
3 o'clock 0.071dB
max 0.077dB

Published specifications vs. our primary measurements

The table below summarizes the measurements published by Denon for the PMA-1700NE compared directly against our own. The published specifications are sourced from Denon’s website, either directly or from the manual available for download, or a combination thereof. With the exception of frequency response, where the Audio Precision bandwidth was extended to 500kHz, assume, unless otherwise stated, 10W into 8ohms and a measurement input bandwidth of 10Hz to 90kHz, and the worst-case measured result between the left and right channels.

Parameter Manufacturer SoundStage! Lab
Amplifier rated output power into 8 ohms (0.07% THD) 70W 89W
Amplifier rated output power into 4 ohms (0.7% THD) 140W 148W
Frequency response 5Hz-100kHz (0,-3dB) 5Hz-100kHz (-0.04,-0.18dB)
THD (1kHz, 8 ohms, 35W) 0.01% 0.002%
Damping factor (1kHz) >100 376
Input sensivity (phono, MM) 2.5mVrms 2mVrms
Input sensivity (phono, MC) 0.2mVrms 0.19mVrms
Input impedance (phono, MM) 47k ohms 52.8k ohms
RIAA deviation (20Hz-20kHz, MM/MC) ±0.5dB ±0.5dB
Phono maximum input (1% THD, 1kHz, MM) 130mVrms 160mVrms
Phono maximum input (1% THD, 1kHz, MC) 10mVrms 15.5mVrms
Input sensitivity (line-level) 125mVrms 120mVrms
Input impedance (line-level) 19k ohms 21.5k ohms
Input sensitivity (ext. pre input) 0.85Vrms 0.83Vrms
Input impedance (ext. pre input) 47k ohms 77.1k ohms
Signal-to-noise ratio (phono, MM, A-weighted, rated output) 89dB 87.2dB
Signal-to-noise ratio (phono, MC, A-weighted, rated output) 74dB 67.8dB
Signal-to-noise ratio (line-level, A-weighted, rated output) 107dB 112.1dB

Our primary measurements revealed the following using the line-level analog input and digital coaxial input (unless specified, assume a 1kHz sine wave at 2Vrms or 0dBFS, 10W output, 8-ohm loading, 10Hz to 90kHz bandwidth):

Parameter Left channel Right channel
Maximum output power into 8 ohms (1% THD+N, unweighted) 96W 96W
Maximum output power into 4 ohms (1% THD+N, unweighted) 160W 160W
Maximum burst output power (IHF, 8 ohms) 96W 96W
Maximum burst output power (IHF, 4 ohms) 173W 173W
Continuous dynamic power test (5 minutes, both channels driven) passed passed
Crosstalk, one channel driven (10kHz) -81.7dB -81.2dB
Damping factor 377 391
Clipping no-load output voltage (instantaneous power into 8 ohms) 29Vrms 29Vrms
DC offset <-4mV <-7mV
Gain (preamp section) 16.7dB 16.8dB
Gain (maximum volume) 45.8dB 45.9dB
IMD ratio (CCIF, 18kHz + 19kHz stimulus tones, 1:1) <-92dB <-92dB
IMD ratio (SMPTE, 60Hz + 7kHz stimulus tones, 4:1 ) <-92dB <-84dB
Input impedance (line input) 21.5k ohms 21.6k ohms
Input sensitivity (for rated power, maximum volume) 122mVrms 120mVrms
Noise level (A-weighted) <88uVmrs <92uVmrs
Noise level (unweighted) <306uVmrs <320uVmrs
Output impedance (line-out) 683 ohms 693 ohms
Signal-to-noise ratio (full power, A-weighted, 2Vrms in) 112.3dB 112.1dB
Signal-to-noise ratio (full power, unweighted, 2Vrms in) 103.8dB 103.8dB
Signal-to-noise ratio (full power, A-weighted, max volume) 97.5dB 97.4dB
Dynamic range (full power, A-weighted, digital 24/96) 110.5dB 110.4dB
Dynamic range (full power, A-weighted, digital 16/44.1) 95.8dB 96.0dB
THD ratio (unweighted) <0.0008% <0.0020%
THD ratio (unweighted, digital 24/96) <0.0006% <0.0011%
THD ratio (unweighted, digital 16/44.1) <0.0008% <0.0013%
THD+N ratio (A-weighted) <0.0013% <0.0025%
THD+N ratio (A-weighted, digital 24/96) <0.0012% <0.0016%
THD+N ratio (A-weighted, digital 16/44.1) <0.0020% <0.0023%
THD+N ratio (unweighted) <0.0035% <0.0020%
Minimum observed line AC voltage 122VAC 122VAC

For the continuous dynamic power test, the PMA-1700NE was able to sustain 155W into 4 ohms (~2% THD) using an 80Hz tone for 500ms, alternating with a signal at -10dB of the peak (15.5W) for 5 seconds, for 5 continuous minutes without inducing a fault or the initiation of a protective circuit. This test is meant to simulate sporadic dynamic bass peaks in music and movies. During the test, the top of the PMA-1700NE was warm to the touch, but did not cause discomfort.

Our primary measurements revealed the following using the phono-level input, MM configuration (unless specified, assume a 1kHz 5mVrms sine-wave input, 10W output, 8-ohm loading, 10Hz to 90kHz bandwidth):

Parameter Left channel Right channel
Crosstalk, one channel driven (10kHz) -69.6dB -68.9dB
DC offset <-4mV <-7mV
Gain (default phono preamplifier) 35.6dB 35.8dB
IMD ratio (CCIF, 18kHz + 19kHz stimulus tones, 1:1) <-86dB <-87dB
IMD ratio (CCIF, 3kHz + 4kHz stimulus tones, 1:1) <-94dB <-90dB
Input impedance 52.8k ohms 52.0k ohms
Input sensitivity (to max power with max volume) 2mVrms 2mVrms
Noise level (A-weighted) <450uVrms <622uVrms
Noise level (unweighted) <1.4mVrms <1.8mVrms
Overload margin (relative 5mVrms input, 1kHz) 30.1dB 30.1dB
Signal-to-noise ratio (full rated power, A-weighted) 89.0dB 87.2dB
Signal-to-noise ratio (full rated power, unweighted) 77.0dB 77.3dB
THD (unweighted) <0.0012% <0.0018%
THD+N (A-weighted) <0.0052% <0.0070%
THD+N (unweighted) <0.016% <0.019%

Our primary measurements revealed the following using the phono-level input, MC configuration (unless specified, assume a 1kHz 0.5mVrms sine-wave input, 10W output, 8-ohm loading, 10Hz to 90kHz bandwidth):

Parameter Left channel Right channel
Crosstalk, one channel driven (10kHz) -63.8dB -45.9dB
DC offset <-4mV <-7mV
Gain (default phono preamplifier) 56.0dB 56.1dB
IMD ratio (CCIF, 18kHz + 19kHz stimulus tones, 1:1) <-78dB <-75dB
IMD ratio (CCIF, 3kHz + 4kHz stimulus tones, 1:1) <-78dB <-75dB
Input impedance 141 ohms 141 ohms
Input sensitivity (to max power with max volume) 193uVrms 189uVrms
Noise level (A-weighted) <4.5mVrms <6mVrms
Noise level (unweighted) <14mVrms <17mVrms
Overload margin (relative 5mVrms input, 1kHz) 29.8dB 29.8dB
Signal-to-noise ratio (full rated power, A-weighted) 69.4dB 67.8dB
Signal-to-noise ratio (full rated power, unweighted) 56.8dB 56.9dB
THD (unweighted) <0.004% <0.005%
THD+N (A-weighted) <0.05% <0.07%
THD+N (unweighted) <0.16% <0.18%

Our primary measurements revealed the following using the analog input at the headphone output (unless specified, assume a 1kHz sine wave, 2Vrms output, 300 ohms loading, 10Hz to 90kHz bandwidth):  

Parameter Left channel Right channel
Maximum output power into 600 ohms (1% THD+N, unweighted) 454mW 454mW
Maximum output power into 300 ohms (1% THD+N, unweighted) 449mW 449mW
Maximum output power into 32 ohms (1% THD+N, unweighted) 105mW 105mW
Gain 45.8dB 45.9dB
Output impedance 440 ohms 441 ohms
Noise level (A-weighted) <23uVrms <23uVrms
Noise level (unweighted) <63uVrms <63uVrms
Signal-to-noise (A-weighted, ref. max output voltage) 113.2dB 113.2dB
Signal-to-noise (unweighted, ref. max output voltage) 104.5dB 104.6dB
THD ratio (unweighted) <0.0006% <0.0006%
THD+N ratio (A-weighted) <0.0013% <0.0013%
THD+N ratio (unweighted) <0.0031% <0.0031%

Frequency response (8-ohm loading, line-level input)

frequency response

In our frequency-response plots above, measured across the speaker outputs at 10W into 8 ohms, the PMA-1700NE is perfectly flat within the audioband (20Hz to 20kHz) and well beyond. At the extremes, the PMA-1700NE is essentially at 0dB at 5Hz and just below -0.5dB at 200kHz, making “wide bandwidth audio amplifier” an apt descriptor for the PMA-1700NE. In the chart above and most of the charts below, only a single trace may be visible. This is because the left channel (blue or purple trace) is performing identically to the right channel (red or green trace), and so they perfectly overlap, indicating that the two channels are ideally matched.

Frequency response (8-ohm loading, line-level input, bass and treble controls)

frequency response

Above are frequency-response plots measured at the speaker-level outputs into 8 ohms, with the bass and treble controls set to maximum (blue/red plots) and minimum (purple/green plots). We see that for the bass and treble controls, roughly +/-7dB of gain/cut is available at 20Hz and 20kHz.

Phase response (8-ohm loading, line-level input)

phase response

Above are the phase response plots from 20Hz to 20kHz for the line-level input measured across the speaker outputs at 10W into 8 ohms. The tone controls were not engaged. The PMA-1700NE does not invert polarity and exhibits, at worst, about 30 degrees (at 20kHz) of phase shift within the audioband.

Frequency response vs. input type (analog and 16/44.1, 24/96, and 24/192 inputs with 8-ohm loading, left channel only)

frequency response vs input type

The chart above shows the PMA-1700NE’s frequency response as a function of input type measured across the speaker outputs at 10W into 8 ohms. The green trace is the same analog input data from the previous chart (but limited to 80kHz). The blue trace is for a 16-bit/44.1kHz dithered digital input signal from 5Hz to 22kHz using the coaxial input, the purple trace is for a 24/96 dithered digital input signal from 5Hz to 48kHz, and the pink trace is for a 24/192 dithered digital input signal from 5Hz to 96kHz. The 16/44.1 data exhibits brickwall-type filtering, with a -3dB point at 20.9kHz. The 24/96 and 24/192 kHz data yielded -3dB points at 45.4kHz and 59.8kHz, respectively. There is no evidence to suggest that the PMA-1700NE digitizes incoming analog signals.

Frequency response (8-ohm loading, MM phono input)

frequency response phono mm

The chart above shows the frequency response for the phono input (MM). What is shown is the deviation from the RIAA curve, where the input signal sweep is EQ’d with an inverted RIAA curve supplied by Audio Precision (i.e., zero deviation would yield a flat line at 0dB). With the PMA-1700NE, we see a maximum deviation within the audioband of about +0.5dB at 20kHz.

Frequency response (8-ohm loading, MC phono input)

frequency response phono mm

The chart above shows the frequency response for the phono input (MM). Like the MM chart above, what is shown is the deviation from the RIAA curve, where the input signal sweep is EQ’d with an inverted RIAA curve supplied by Audio Precision (i.e., zero deviation would yield a flat line at 0dB). We see a maximum deviation within the audioband of about +0.4dB between 10kHz and 20kHz.

Phase response (MM input)

phase response phono mm

Above is the phase-response plot from 20Hz to 20kHz for the phono input (MM), measured across the speaker outputs at 10W into 8 ohms. For the phono input, since the RIAA equalization curve must be implemented, which ranges from +19.9dB (20Hz) to -32.6dB (90kHz), phase shift at the output is inevitable. Here we find a worst case of about -60 degrees at 200Hz and 5kHz. The PMA-1700NE does not invert polarity.

Phase response (MC input)

phase response phono mc

Above is the phase-response plot from 20Hz to 20kHz for the phono input (MC), measured across the speaker outputs at 10W into 8 ohms. For the phono input, since the RIAA equalization curve must be implemented, which ranges from +19.9dB (20Hz) to -32.6dB (90kHz), phase shift at the output is inevitable. Here we find a worst case of about -60 degrees at 200Hz and 5kHz. The PMA-1700NE does not invert polarity.

Digital linearity (16/44.1 and 24/96 data)

digital linearity

The chart above shows the results of a linearity test for the coaxial digital input for both 16/44.1 (blue/red) and 24/96 (purple/green) input data, measured at the line level output of the PMA-1700NE. The digital input is swept with a dithered 1kHz input signal from -120dBFS to 0dBFS, and the output is analyzed by the APx555. The ideal response would be a straight, flat line at 0dB. Both data were essentially perfect as of -100dBFS down to 0dBFS. At -120dBFS, the 16/44.1 data were only +2 to 2.5dB above reference, while the 24/96 data were within 1dB of reference.  

Impulse response (24/44.1 data)

impulse response 2444 1

The chart above shows the impulse responses for the PMA-1700NE, fed to the coaxial digital input, measured at the line-level output, for a looped 24/44.1 test file that moves from digital silence to full 0dBFS (all “1”s), for one sample period, then back to digital silence. Here we find a symmetrical impulse response with minimal pre- and post-ringing.

J-Test (coaxial)

jtest coax 2448

The chart above shows the results of the J-Test test for the coaxial digital input measured at the line-level output of the PMA-1700NE. The J-Test was developed by Julian Dunn in the 1990s. It is a test signal—specifically, a -3dBFS undithered 12kHz squarewave sampled (in this case) at 48kHz (24 bits). Since even the first odd harmonic (i.e., 36kHz) of the 12kHz squarewave is removed by the bandwidth limitation of the sampling rate, we are left with a 12kHz sinewave (the main peak). In addition, an undithered 250Hz squarewave at -144dBFS is mixed with the signal. This test file causes the 22 least-significant bits to constantly toggle, which produces strong jitter spectral components at the 250Hz rate and its odd harmonics. The test file shows how susceptible the DAC and delivery interface are to jitter, which would manifest as peaks above the noise floor at 500Hz intervals (e.g., 250Hz, 750Hz, 1250Hz, etc.). Note that the alternating peaks are in the test file itself, but at levels of -144dBrA and below.  The test file can also be used in conjunction with artificially injected sine-wave jitter by the Audio Precision, to show how well the DAC rejects jitter.

The coaxial input exhibits obvious peaks throughout the audioband, as high as -100dBrA on both sides of the 12kHz fundamental. This is a relatively poor J-Test result, indicating that PMA-1700NE DAC may be susceptible to jitter.

J-Test (optical)

jtest optical 2448

The chart above shows the results of the J-Test test for the optical digital input measured at the line-level output of the PMA-1700NE. The result is similar but slightly worse than for the coaxial input. The highest peaks are just above -90dBrA, on both sides of the 12kHz fundamental. This is a relatively poor J-Test result, indicating that PMA-1700NE DAC may be susceptible to jitter.

J-Test with 10ns of injected jitter (coaxial)

jtest coax 2448

The coaxial input was also tested for jitter immunity by injecting artificial sine-wave jitter at 2kHz, which would manifest as sidebands at 10kHz and 14kHz without any jitter rejection. Jitter immunity proved poor, as predicted based on the previous results, with visible sidebands at only the 10ns jitter level, at -70dBrA.

J-Test with 100ns of injected jitter (coaxial)

jtest coax 2448

The coaxial input was also tested for jitter immunity by injecting artificial sine-wave jitter at 2kHz, which would manifest as sidebands at 10kHz and 14kHz without any jitter rejection. Jitter immunity proved poor as predicted, based on the other results, with visible sidebands at the 100ns jitter level, at -50dBrA. The optical input (not shown) performed similarly with the same 100ns jitter level injected.

Wideband FFT spectrum of white noise and 19.1kHz sine-wave tone (coaxial input)

wideband fft noise plus 19 1khz 1644 1kHz

The chart above shows a fast Fourier transform (FFT) of the PMA-1700NE’s line-level output with white noise at -4dBFS (blue/red) and a 19.1 kHz sine wave at 0dBFS fed to the coaxial digital input, sampled at 16/44.1. The fairly steep roll-off around 20kHz in the white-noise spectrum shows the behavior of the PMA-1700NE’s reconstruction filter. There are no aliased image peaks within the audioband visible above the -125dBrA noise floor. The primary aliasing signal at 25kHz is highly suppressed at -105dBrA, while the second and third distortion harmonics (38.2, 57.3kHz) of the 19.1kHz tone are at -80dBrA and below.

RMS level vs. frequency vs. load impedance (1W, left channel only)

rms level vs frequency vs load impedance

The chart above shows RMS level (relative to 0dBrA, which is 1W into 8ohms or 2.83Vrms) as a function of frequency, for the analog line-level input swept from 5Hz to 100kHz. The blue plot is into an 8-ohm load, the purple is into a 4-ohm load, the pink plot is an actual speaker (Focal Chora 806, measurements can be found here), and the cyan plot is no load connected. The chart below . . .

rms level vs frequency vs load impedance

. . . is the same but zoomed in to highlight differences. Here we find that maximum deviation between no load and a 4-ohm load is very small, at just over 0.04dB. This is an indication of a very high damping factor, or low output impedance. With a real speaker, maximum deviations in RMS level were smaller, at about 0.035dB.

THD ratio (unweighted) vs. frequency vs. output power

thd ratio unweighted vs frequency vs output power

The chart above shows THD ratios at the output into 8 ohms as a function of frequency for a sine-wave stimulus at the analog line-level input. The blue and red plots are for left and right channels at 1W output into 8 ohms, purple/green at 10W, and pink/orange at 63W. Power was varied using the volume control. The left channel consistently outperformed the right channel by as much as 5dB at all power levels. The 1W and 10W data are nearly identical, ranging between 0.005% at 20Hz, down to 0.0007% from 200Hz to 1kHz, then up to 0.01% at 20kHz for the left channel. The 63W THD values were only slightly higher, from a low of 0.0015% in the midrange frequencies, up to 0.02% at 20kHz for the left channel.

THD ratio (unweighted) vs. frequency at 10W (MM and MC phono inputs)

thd ratio unweighted vs frequency vs phono mm mc

The chart above shows THD ratios as a function of frequency plots for the phono input measured across an 8-ohm load at 10W. The blue and red plots are for left and right channels with the MM configuration, purple/green for MC. The input sweep is EQ’d with an inverted RIAA curve. For the MM configuration, the THD values vary from around 0.02% (20Hz) down to 0.001% (200Hz-1kHz), then up to 0.006% (20kHz), once again for the left channel, which outperformed the right channel by as much as 5dB. For the MC configurationm, the THD values vary from around 0.2% (20Hz) down to 0.003% (1kHz-2kHz), then up to 0.006% (20kHz), once again for the left channel. For the MM input, the left channel outperformed the right channel only between 1kHz to 20kHz.

THD ratio (unweighted) vs. output power at 1kHz into 4 and 8 ohms

thd ratio unweighted vs output power at 4 8 ohms

The chart above shows THD ratios measured at the output of the PMA-1700NE as a function of output power for the analog line-level input, for an 8-ohm load (blue/red for left/right channels) and a 4-ohm load (purple/green for left/right channels). The right channel into 4 ohms exhibited much higher THD ratios (20-30dB) than the left channel between 0.5W and 100W. The test was repeated to rule out any anomalies, and the results were repeatable. Into 8 ohms, the left channel outperformed the right channel by 10dB or less. Both the left channel data (8 and 4 ohms) are quite similar, a testament to the PMA-1700NE’s high damping factor. These ranged from about 0.002% at 50mW, down to nearly 0.0005% at 5-50W, then a small rise to the knees (near 70W into 8 ohms, near 100W into 4 ohms). The 1% THD marks were hit at 96W (8 ohm) and 160W (4 ohm).

THD+N ratio (unweighted) vs. output power at 1kHz into 4 and 8 ohms

thd n ratio unweighted vs output power at 4 8 ohms

The chart above shows THD+N ratios measured at the output of the PMA-1700NE as a function of output power for the analog line-level input, for an 8-ohm load (blue/red for left/right channels) and a 4-ohm load (purple/green for left/right channels). Aside from the right channel into 4 ohms (described above), overall, THD+N values for both loads were similar up to 60W. The 8-ohm data ranged from 0.02% down to just below 0.003%. The 8-ohm data outperformed the 4-ohm data by 3-4dB.

THD ratio (unweighted) vs. frequency at 8, 4, and 2 ohms (left channel only)

thd vs frequency load

The chart above shows THD ratios measured at the output of the PMA-1700NE as a function of frequency into three different loads (8/4/2 ohms) for a constant input voltage that yields 10W at the output into 8 ohms (and roughly 20W into 4 ohms, and 40W into 2 ohms) for the analog line-level input. The 8-ohm load is the blue trace, the 4-ohm load the purple trace, and the 2-ohm load the pink trace. The 8-ohm and 4-ohm track very closely throughout the audioband, between 0.001% and 0.01%. The 2-ohm data yielded higher distortion, hovering between 0.003% and 0.015% from 20Hz to 20kHz. Overall, this is a good result and shows how stable the PMA-1700NE is into low impedances.

THD ratio (unweighted) vs. frequency into 8 ohms and real speakers (left channel only)

thd vs frequency vs speakers

The chart above shows THD ratios measured at the output of the PMA-1700NE as a function of frequency into an 8-ohm load and two different speakers for a constant output voltage of 2.83Vrms (1W into 8 ohms) for the analog line-level input. The 8-ohm load is the blue trace, the purple plot is a two-way speaker (Focal Chora 806, measurements can be found here), and the pink plot is a three-way speaker (Paradigm Founder Series 100F, measurements can be found here). Aside from an increase in THD ratios for the two-way speaker below 40Hz, rising as high as 0.03% at 20Hz, all three plots are remarkebly close. This is yet another example showing how impervious the PMA-1700NE is to various loads due to its very high damping factor. Overall, THD ratios varied from 0.0005% to 0.01%.

IMD ratio (CCIF) vs. frequency into 8 ohms and real speakers (left channel only)

IMD CCIF vs frequency vs speakers

The chart above shows intermodulation distortion (IMD) ratios measured at the output of the PMA-1700NE  as a function of frequency into an 8-ohm load and two different speakers for a constant output voltage of 2.83Vrms (1W into 8 ohms) for the analog line-level input. Here the CCIF IMD method is used, where the primary frequency is swept from 20kHz (F1) down to 2.5kHz, and the secondary frequency (F2) is always 1kHz lower than the primary, with a 1:1 ratio. The CCIF IMD analysis results are the sum of the second (F1-F2 or 1kHz) and third modulation products (F1+1kHz, F2-1kHz). The 8-ohm load is the blue trace, the purple plot is a two-way speaker (Focal Chora 806, measurements can be found here), and the pink plot is a three-way speaker (Paradigm Founder Series 100F, measurements can be found here). All three data sets track fairly closely, with the expection of the three-way speaker showing higher IMD values above 10kHz, differing by almost 10dB at 20kHz. Overall IMD ratios were hovering around 0.001%.

IMD ratio (SMPTE) vs. frequency into 8 ohms and real speakers (left channel only)

IMD SMPTE vs frequency vs speakers

The chart above shows IMD ratios measured at the output of the PMA-1700NE as a function of frequency into an 8-ohm load and two different speakers for a constant output voltage of 2.83Vrms (1W into 8 ohms) for the analog line-level input. Here, the SMPTE IMD method is used, where the primary frequency (F1) is swept from 250Hz down to 40Hz, and the secondary frequency (F2) is held at 7kHz with a 4:1 ratio. The SMPTE IMD analysis results consider the second (F2 ± F1) through the fifth (F2 ± 4xF1) modulation products. The 8-ohm load is the blue trace, the purple plot is a two-way speaker (Focal Chora 806, measurements can be found here), and the pink plot is a three-way speaker (Paradigm Founder Series 100F, measurements can be found here). All three data sets are close enough to be judged as identical, hovering around the 0.003% mark.

FFT spectrum – 1kHz (line-level input, Analog Mode turned on)

FFT spectrum 1khz

Shown above is the fast Fourier transform (FFT) for a 1kHz input sine-wave stimulus, measured at the output across an 8-ohm load at 10W for the analog line-level input. We see that the signal’s second harmonic, at 2kHz, is at -100/95dBrA (left/right), or 0.001/0.002%, while all subsequent harmonics are below the -110dBrA, or 0.0003% mark. Power-supply-related noise at the fundamental (60Hz) frequency, as well as both even and odd harmonics, are evident, at -100dBrA, or 0.001%, levels and below.

FFT spectrum – 1kHz (line-level input, Analog Mode turned off)

FFT spectrum 1khz

Shown above is the fast Fourier transform (FFT) for a 1kHz input sine-wave stimulus, measured at the output across an 8-ohm load at 10W for the analog line-level input, with Analog 2 Mode turned off (i.e., with the front display and digital electronics turned on). We see effectively no difference when compared with the FFT above with Analog Mode engaged.

FFT spectrum – 1kHz (digital input, 16/44.1 data at 0dBFS)

fft spectrum 1khz 1644 1 0dbfs

Shown above is the fast Fourier transform (FFT) for a 1kHz input sine-wave stimulus, measured at the output across an 8-ohm load at 10W for the coaxial digital input, sampled at 16/44.1. Signal harmonics and power-supply-related noise peaks are very similar in level to the analog input FFT above, although with a higher noise floor due to the limitations of the 16-bit depth.

FFT spectrum – 1kHz (digital input, 24/96 data at 0dBFS)

fft spectrum 1khz 2496 0dbfs

Shown above is the fast Fourier transform (FFT) for a 1kHz input sine-wave stimulus, measured at the output across an 8-ohm load at 10W for the coaxial digital input, sampled at 24/96. Signal harmonics and power-supply-related noise peaks are very similar in level to the analog input FFT above.

FFT spectrum – 1kHz (digital input, 16/44.1 data at -90dBFS)

fft spectrum 1khz 2444 1 90dbfs

Shown above is the FFT for a 1kHz -90dBFS dithered 16/44.1 input sine-wave stimulus at the coaxial digital input, measured at the output across an 8-ohm load. We see the 1kHz primary signal peak, at the correct amplitude, and low-level power-supply-related noise harmonics at -105dBrA, or 0.0006%, and below.

FFT spectrum – 1kHz (digital input, 24/96 data at -90dBFS)

fft spectrum 1khz 2496 90dbfs

Shown above is the FFT for a 1kHz -90dBFS dithered 24/96 input sine-wave stimulus at the coaxial digital input, measured at the output across an 8-ohm load. We see the 1kHz primary signal peak, at the correct amplitude, and power-supply-related noise harmonics at -105dBrA, or 0.0006%, and below.

FFT spectrum – 1kHz (MM phono input)

fft spectrum 1khz phono mm

Shown above is the FFT for a 1kHz input sine-wave stimulus, measured at the output across an 8-ohm load at 10W for the MM phono configuration. We see the second (2kHz) and third (3kHz) signal harmonics at low levels: -100 and -110dBrA, respectively, or 0.001% and 0.0003%. Power-supply-related odd harmonics, and the fundamental, can be seen at 60, 180 and 300Hz at -80dBrA, or 0.01%. Even-order power-supply-related peaks (120, 240, 360Hz, etc) can also be seen but at lower amplitudes.

FFT spectrum – 1kHz (MC phono input)

fft spectrum 1khz phono mc

Shown above is the FFT for a 1kHz input sine-wave stimulus, measured at the output across an 8-ohm load at 10W for the MC phono configuration. Signal related harmonics are difficult to distinguish from the high-order power-supply-related noise harmonics that dominate the FFT. These range from -60dBrA, or 0.1%, at low frequencies (60/180/300Hz), down to -100dBrA, or 0.001%, at high frequencies.

FFT spectrum – 50Hz (line-level input)

fft spectrum 50hz

Shown above is the FFT for a 50Hz input sine-wave stimulus measured at the output across an 8-ohm load at 10W for the analog line-level input. The X axis is zoomed in from 40Hz to 1kHz, so that peaks from noise artifacts can be directly compared against peaks from the harmonics of the signal. The most dominant (non-signal) peaks are the second signal harmonic (100Hz) at -95dBrA (right), or 0.002%, and the second power-supply-related harmonic (120Hz), also at -95dBrA.

FFT spectrum – 50Hz (MM phono input)

fft spectrum 50hz phono mm

Shown above is the FFT for a 50Hz input sine-wave stimulus measured at the output across an 8-ohm load at 10W for the MM phono configuration. The X axis is zoomed in from 40 Hz to 1kHz, so that peaks from noise artifacts can be directly compared against peaks from the harmonics of the signal. The most predominant (non-signal) peaks are from the 60Hz power supply fundamental at -80dBrA, or 0.01%, and its third and fifth harmonics (180/300Hz) at the same level. The highest signal related harmonic is at 100Hz, at -100/95dBrA (left/right), or 0.001/0.002%.

FFT spectrum – 50Hz (MC phono input)

fft spectrum 50hz phono mc

Shown above is the FFT for a 50Hz input sine-wave stimulus measured at the output across an 8-ohm load at 10W for the MC phono configuration. The X axis is zoomed in from 40 Hz to 1kHz, so that peaks from noise artifacts can be directly compared against peaks from the harmonics of the signal. The most predominant (non-signal) peaks are from the 60Hz power supply fundamental at -60dBrA, or 0.1%, and its third and fifth harmonics (180/300Hz) at the same level. The highest signal related harmonic is at 100Hz, at -90dBrA, or 0.003%.

Intermodulation distortion FFT (18kHz + 19kHz summed stimulus, line-level input)

intermodulation distortion fft 18khz 19khz summed stimulus

Shown above is an FFT of the intermodulation distortion (IMD) products for an 18kHz + 19kHz summed sine-wave stimulus tone measured at the output across an 8-ohm load at 10W for the analog line-level input. The input RMS values are set at -6.02dBrA so that, if summed for a mean frequency of 18.5kHz, would yield 10W (0dBrA) into 8 ohms at the output. We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -110/100dBrA (left/right), or 0.0003/0.001%, while the third-order modulation products, at 17kHz and 20kHz, are just above (left) and below (right) -110dBrA, or 0.0003%.

Intermodulation distortion FFT (18kHz + 19kHz summed stimulus, coaxial digital input, 16/44.1)

intermodulation distortion fft 18khz 19khz summed stimulus

Shown above is an FFT of the intermodulation distortion (IMD) products for an 18kHz + 19kHz summed sine-wave stimulus tone measured at the output across an 8-ohm load at 10W for the digital coaxial input at 16/44.1. We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -110/100dBrA (left/right), or 0.0003/0.001%, while the third-order modulation products, at 17kHz and 20kHz, are just below -110dBrA, or 0.0003%.

Intermodulation distortion FFT (18kHz + 19kHz summed stimulus, coaxial digital input, 24/96)

intermodulation distortion fft 18khz 19khz summed stimulus

Shown above is an FFT of the intermodulation distortion (IMD) products for an 18kHz + 19kHz summed sinewave stimulus tone measured at the output across an 8-ohm load at 10W for the digital coaxial input at 24/96. We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -110/100dBrA (left/right), or 0.0003/0.001%, while the third-order modulation products, at 17kHz and 20kHz, are just below -110dBrA, or 0.0003%.

Intermodulation distortion FFT (18kHz + 19kHz summed stimulus, MM phono input)

intermodulation distortion FFT 18kHz 19kHz summed stimulus phono mm

Shown above is an FFT of the intermodulation distortion (IMD) products for an 18kHz + 19kHz summed sine-wave stimulus tone measured at the output across an 8-ohm load at 10W for the MM phono input. We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -110/100dBrA (left/right), or 0.0003/0.001%, while the third-order modulation products, at 17kHz and 20kHz, are just below -100dBrA, or 0.001%.

Intermodulation distortion FFT (18kHz + 19kHz summed stimulus, MC phono input)

intermodulation distortion FFT 18kHz 19kHz summed stimulus phono mc

Shown above is an FFT of the intermodulation distortion (IMD) products for an 18kHz + 19kHz summed sine-wave stimulus tone measured at the output across an 8-ohm load at 10W for the MC phono configuration. We find that the second-order modulation product (i.e., the difference signal of 1kHz), while difficult to spot below the power-supply-related high-order noise harmonics, is at -100/90dBrA (left/right), or 0.001/0.003%, while the third-order modulation products, at 17kHz and 20kHz, are just below -100dBrA, or 0.001%.

Square-wave response (10kHz)

square wave response 10kHz

Above is the 10kHz squarewave response using the analog line-level input, at roughly 10W into 8 ohms. Due to limitations inherent to the Audio Precision APx555 B Series analyzer, this graph should not be used to infer or extrapolate the PMA-1700NE ’s slew-rate performance. Rather, it should be seen as a qualitative representation of the PMA-1700NE ’s extended bandwidth. An ideal squarewave can be represented as the sum of a sine wave and an infinite series of its odd-order harmonics (e.g., 10kHz + 30kHz + 50kHz + 70kHz . . .). A limited bandwidth will show only the sum of the lower-order harmonics, which may result in noticeable undershoot and/or overshoot, and softening of the edges. The PMA-1700NE’s squarewave response is superb, showing no visible over/undershoot, or ringing near the sharp corners. 

Damping factor vs. frequency (20Hz to 20kHz)

damping factor vs frequency

The final graph above is the damping factor as a function of frequency. We see a relatively constant and very high damping factor, and both channels tracking closely, between 400 and 350 from 20Hz to 20kHz. This is an exceptional result for an integrated amplifier.

Diego Estan
Electronics Measurement Specialist

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