Linn Majik DSM Streaming Integrated Amplifier Measurements

Link: reviewed by Roger Kanno on SoundStage! Simplifi on January 1, 2026

General Information

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

The Line Majik DSM was conditioned for 1 hour at 1/8th full rated power (~10W 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 Majik DSM offers two line-level analog inputs (RCA), moving-magnet (MC) and moving-coil (MC) phono inputs (RCA), two digital S/PDIF inputs (RCA coaxial and TosLink optical), and other network connections for streaming. In terms of outputs, there are line-level subwoofer and pre-outs (RCA), and a pair of speaker level outputs. Also included is a ¼″ TRS headphone output on the front panel. For the purposes of these measurements, the following inputs were evaluated: coaxial digital (RCA) and the analog line-level and phono MM and MC (RCA) inputs.

Most measurements were made with a 2Vrms line-level analog input or 0dBFS digital input. The signal-to-noise (SNR) measurements were made with the same input signal values but with the volume set to achieve the output power of 74W (into 8 ohms) for 1% THD. For comparison, on the analog input, a SNR measurement was also made with the volume at maximum, but with a lower input signal to achieve the same 74W.

Based on the accuracy and repeatability at various volume levels of the left/right channel matching (see table below), the Majik DSM volume control is operating in the digital domain. Consequently, all analog signals are digitized (sampled at 24/192) at the Majik DSM’s inputs so the unit may apply volume and EQ functions. The volume control offers a total range from -65dB to +34dB (line-level inputs, speaker level outputs) using 100 increments of 1dB.

Because the Majik DSM is a digital amplifier technology that exhibits considerable noise above 20kHz (see FFTs below), our typical input bandwidth filter setting of 10Hz-90kHz was necessarily changed to 10Hz-22.4kHz for all measurements, except for frequency response and for FFTs. In addition, THD versus frequency sweeps were limited to 6kHz to adequately capture the second and third signal harmonics with the restricted-bandwidth setting.

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

Published specifications vs. our primary measurements

The table below summarizes the measurements published by Linn for the Majik DSM compared directly against our own. The published specifications are sourced from Linn’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 1MHz, assume, unless otherwise stated, 10W into 8ohms and a measurement input bandwidth of 10Hz to 22.4kHz, and the worst-case measured result between the left and right channels.

Our primary measurements revealed the following using the line-level analog input and digital coaxial input (unless specified, assume a 1kHz sinewave at 2Vrms or 0dBFS, 10W output, 8-ohm loading, 10Hz to 22.4kHz bandwidth):

For the continuous dynamic power test, the Majik DSM was able to sustain 148W into 4 ohms (~4% THD) using an 80Hz tone for 500ms, alternating with a signal at -10dB of the peak (14.8W) for 5 seconds, for 5 minutes without inducing the fault protection circuit. This test is meant to simulate sporadic dynamic bass peaks in music and movies. During the test, the top of the Majik DSM was slightly warm to the touch.

Our primary measurements revealed the following using the phono-level input, MM configuration (unless specified, assume a 1kHz 5mVrms sinewave input, 10W output, 8-ohm loading, 10Hz to 22.4kHz bandwidth):

Our primary measurements revealed the following using the phono-level input, MC configuration (unless specified, assume a 1kHz 0.5mVrms sinewave input, 10W output, 8-ohm loading, 10Hz to 22.4kHz bandwidth):

Our primary measurements revealed the following using the analog input at the headphone output (unless specified, assume a 1kHz sinewave, 2Vrms input/output, 300 ohms loading, 10Hz to 22.4kHz bandwidth):

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

In our frequency response plots above (relative to 1kHz), measured across the speaker outputs at 10W into 8 ohms, the Majik DSM is near flat within the audioband (20Hz to 20kHz, 0/-0.2dB). The -3dB point is at roughly 55kHz, with sharp high-frequency attenuation. Due to either noise or excessive DC leakage, we could not measure the Majik DSM without a low-pass filter (10Hz) on the analyzer’s inputs. This is why the plot is limited to 10Hz (and not 5Hz). In the graph above and most of the graphs 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 perfectly overlap, indicating that the two channels are ideally matched.

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

The chart above shows the frequency response (relative to 1kHz) measured across the speaker outputs at 10W into 8 ohms, as well as the line-level sub-out frequency response (relative to 20Hz). The subwoofer was engaged in the settings for these measurements, with the cut-off frequency set to 80Hz. The Bass Redirect setting was engaged, which applies a low-pass second order filter to the line-level sub-outs, and a mirror high-pass filter to the main speaker outputs. We see that both traces merge at 80Hz at -6dB, as expected.

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

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 Majik DSM digitizes all incoming analog signals at 24/192, subsequently, true phase delay will be significant as it includes the timing delay associated with the ADC process. Here we see roughly -500000 degrees at 20kHz. Below, is . . .

. . . a phase plot that only shows the excess phase (timing delays removed). Here we see +20 degrees at 20Hz (which should be ignored because the low-pass filter on the analyzer inputs had to be engaged), and +40 degrees at 20kHz.

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

The chart above shows the frequency response (relative to 1kHz) for the MM phono input. 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 very flat response from 20Hz to 3kHz (indicative of RIAA EQ applied in the digital domain), followed by a steep rise in response (+1dB at 20kHz), peaking at 45kHz (+4dB).

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

The chart above shows the frequency response for the MC phono input. We see a very flat response across the audioband (0dB at 20Hz, -0.2dB at 20kHz).

Phase response (8-ohm loading, MM input, excess)

Above is the excess phase response plot from 20Hz to 20kHz for the MM phono input, measured across the speaker outputs at 10W into 8 ohms. The Majik DSM does not invert polarity. 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 +100 degrees at 20Hz and -5 degrees at 6-8kHz.

Phase response (8-ohm loading, MC input, excess)

Above is the excess phase response plot from 20Hz to 20kHz for the MC phono input, measured across the speaker outputs at 10W into 8 ohms. We find the same result as with the MM input above.

Frequency response vs. input type (8-ohm loading, left channel only)

The chart above shows the Majik DSM’s frequency response (relative to 1kHz) as a function of input type measured across the speaker outputs at 10W into 8 ohms. The two green traces are the same analog input data from the speaker-level frequency-response graph above. The blue and red traces are for a 16-bit/44.1kHz dithered digital input signal from 5Hz to 22kHz using the coaxial input, the purple and green traces are for a 24/96 dithered digital input signal from 5Hz to 48kHz, and the pink and orange traces are for a 24/192 dithered digital input signal. The -3dB points are roughly: 21kHz for the 16/44.1 data, 40kHz for the 24/96, and 55kHz for the 24/192 data. The analog plots follow the 24/192 plots as expected, because analog signals are sampled at 24/192.

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

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 pre-outputs of the Majik DSM, where 0dBFS was set to yield 1Vrms. For this test, 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. The 24/96 data were at +1dB at -120dBFS, while the 16/44.1 data were +2/3dB at -120dBFS.

Impulse response (24/44.1 data)

The graph above shows the impulse response 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, measured at the line-level pre-outs of the Majik DSM. We find a typical symmetrical sinc-function response.

J-Test (coaxial)

The chart above shows the results of the J-Test test for the coaxial digital input measured at the line-level pre-outputs of the Majik DSM where 0dBFS is set to 1Vrms. J-Test was developed by Julian Dunn the 1990s. It is a test signal—specifically, a -3dBFS undithered 12kHz squarewave sampled (in this case) at 48kHz (24bit). 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 sinewave jitter by the Audio Precision, to show how well the DAC rejects jitter.

Here we see a relatively strong J-Ttest result. While several peaks can be seen in the audioband, they are very low in amplitude and range from -135dBFS down to -150dBFS. This is an indication that the Majik DSM DAC may have strong jitter immunity.

J-Test (optical)

The chart above shows the results of the J-Test test for the optical digital input measured at the line-level pre-outputs of the Majik DSM. The optical input yielded essentially the same results compared to the coaxial input.

J-Test (coaxial, 100ns jitter)

The chart above shows the results of the J-Test test for the coaxial digital input measured at the line-level output of the Majik DSM, with an additional 100ns of 2kHz sinewave jitter injected by the APx555. The telltale peaks at 10kHz and 12kHz cannot be seen, indicating strong jitter rejection. The optical input yielded the same result.

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

The chart above shows a fast Fourier transform (FFT) of the Majik DSM’s line-level pre-outputs with white noise at -4dBFS (blue/red) and a 19.1 kHz sinewave at 0dBFS fed to the coaxial digital input, sampled at 16/44.1. The steep roll-off around 20kHz in the white-noise spectrum shows brickwall-type filtering. There are no low-level aliased image peaks within the audioband. The primary aliasing signal at 25kHz is highly suppressed at -140dBrA, while the second and third distortion harmonics (38.2, 57.3kHz) of the 19.1kHz signal are at -105 and -120dBFS.

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

The chart above shows RMS level (relative to 0dBrA, which is 1W into 8 ohms or 2.83Vrms) as a function of frequency, for the analog line-level input swept from 10Hz to 50kHz. 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 . . .

. . . is the same but zoomed in to highlight differences. Here we see that the deviations between no load and 4 ohms are roughly 0.2dB. With a real speaker load, deviations measured lower, at roughly 0.1dB. At frequencies above 3-4kHz, there appears to be some sort of active compensation occurring at the outputs (the no load and 4-ohm load plots cross over at 6kHz, which would imply a negative output impedance).

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

The chart above shows THD ratios at the speaker-level outputs into 8 ohms as a function of frequency for a sinewave stimulus at the analog line-level input. The blue and red plots are for the left and right channels at 1W output into 8 ohms, purple/green at 10W, and pink/orange at 65W. The power was varied using the Majik DSM’s volume control. The 1W THD ratios were the lowest, ranging from 0.0005% from 20Hz to 1kHz, then up to 0.002% at 20kHz. The 10W THD ratios were slightly higher ranging from 0.0005% to 0.004%. At 65W, THD ratios ranged from 0.0005% at lower frequencies, up to roughly 0.005-0.01% from 150Hz to 20kHz.

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

The chart above shows THD ratios as a function of frequency plots for the MM (blue/red) and MC (purple/green) phono inputs measured across an 8-ohm load at 10W. For this test, the input sweep was EQ’d with an inverted RIAA curve. The THD values for the MM configuration vary from around 0.03% (20Hz) down to 0.002% (2/3kHz left channel), then up to 0.005% at 20kHz. The THD values for the MC configuration vary from around 0.01% (20Hz) down to 0.002% (2/3kHz), then up to 0.005% at 20kHz. It should be noted that often the limiting factor in THD measurements for phono inputs is the higher noise floor. The analyzer cannot assign a THD ratio for a signal harmonic peak it cannot see above the noise floor, and therefore the THD ratio is assigned the value of the noise floor relative to the signal.

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

The chart above shows THD ratios measured at the speaker-level outputs of the Majik DSM as a function of output power for the analog line-level input for an 8-ohm load (blue/red for left/right) and a 4-ohm load (purple/green for left/right), with the volume set to maximum. THD ratios into 4 and 8 ohms are close (with 3-4dB below 10W). For the 8-ohm load, they range from 0.015% at 50mW, down to just above 0.001% in the 10 to 50W range. The “knee” into 8 ohms can be found just past 55W, with the 1% THD mark hit at 74W. For the 4-ohm load, THD ratios range from 0.02% at 50mW, down to 0.002% at 10W, then up to 0.003% up to the “knee,” just past 100W, with the 1% THD mark hit at 136W.

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

The chart above shows THD+N ratios measured at the speaker-level outputs of the Majik DSM as a function of output power for the analog line-level input for an 8-ohm load (blue/red for left/right) and a 4-ohm load (purple/green for left/right). THD+N ratios into 4 and 8 ohms are close (with 3-4dB). They range from 0.1-0.2% at 50mW, down to 0.005-0.006% at the “knees.”

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

The chart above shows THD ratios measured at the output of the Majik DSM 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 and the 4-ohm load the purple trace. We find a roughly 5-10dB increase in THD from 8 to 4 to 2 ohms. These ranged from 0.0005% from 20Hz to 300Hz, then up to 0.004% at 20kHz for the 8-ohm load. The 4-ohm load ranged from 0.0006% at 20-30Hz up to 0.005% at 20kHz. The 2-ohm load ranged from 0.001% at 20Hz up to 0.006% from 1-3kHz, then up to 0.008% at 20kHz.

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

The chart above shows THD ratios measured at the output of the Majik DSM 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 thee-way speaker (Paradigm Founder Series 100F, measurements can be found here). Generally, THD ratios into the real speakers were much higher than those measured across the resistive dummy load, from 20Hz to 1kHz. The differences ranged from 0.1% at 20Hz for the two-way speaker (0.01% for the three-way speaker) versus 0.0005% for the resistive load, and 0.004% at 20kHz into the three-way speaker versus 0.002% for the resistive load. Between 1kHz and 3kHz, all three THD traces were very close, around the 0.0006-0.0007% mark.

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

The chart above shows intermodulation distortion (IMD) ratios measured at the output of the Majik DSM 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 was 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). We find that all three IMD traces are close to one another, ranging from 0.001-0.002% at 2.5kHz, up to a peak of 0.05% at around 15kHz.

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

The chart above shows IMD ratios measured at the output of the Majik 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 was 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 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). We find very similar IMD ratios into all three loads; a flat 0.003% across the sweep.

FFT spectrum – 1kHz (line-level input)

Shown above is the fast Fourier transform (FFT) for a 1kHz input sinewave 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 (2kHz) and third (3kHz) harmonics dominate at a -110/-105dBrA, or 0.0003/0.0006%. There are subsequent signal harmonics visible at and below the -120dBrA, or 0.0001%, level. On the right side of the signal peak, we find no power-supply-related noise peaks above the -130 to -140dBrA noise floor. We also see a rise in the noise floor above 20kHz, characteristic of class-D amps.

FFT spectrum – 1kHz (MM phono input)

Shown above is the fast Fourier transform (FFT) for a 1kHz input sinewave stimulus, measured at the output across an 8-ohm load at 10W for the phono MM input. We see that the signal’s second (2kHz) and third (3kHz) harmonics dominate at a -110/-105dBrA, or 0.0003/0.0006%, the same as with the line-level FFT above. On the right side of the signal peak, we find two main power-supply-related noise peaks: the primary (60Hz) at -80dBrA, or 0.01%, and the third harmonic (180Hz) at -85dBrA, or 0.006%.

FFT spectrum – 1kHz (MC phono input)

Shown above is the fast Fourier transform (FFT) for a 1kHz input sinewave stimulus, measured at the output across an 8-ohm load at 10W for the phono MC input. We see that the signal’s second (2kHz) harmonic can be seen amongst the power-supply-related noise peaks at -100dBrA, or 0.001%. On the right side of the signal peak, we find the two most significant main power-supply related noise peaks at 60Hz (-60dBrA, or 0.1%) and 180Hz (-65dBrA, or 0.06%). A multitude of subsequent power-supply-related noise harmonics can be seen at and below -80dBrA, or 0.01%.

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

Shown above is the fast Fourier transform (FFT) for a 1kHz input sinewave stimulus, measured at the output across an 8-ohm load at 10W for the coaxial digital input, sampled at 16/44.1. We see that the signal’s second (2kHz) and third (3kHz) harmonics dominate at a -110/-105dBrA, or 0.0003/0.0006%.  Subsequent harmonics can be seen at and below the -120dBrA, or 0.0001%, level. No visible power-supply-related noise peaks can be seen above the -135dBrA noise floor.

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

Shown above is the fast Fourier transform (FFT) for a 1kHz input sinewave stimulus, measured at the output across an 8-ohm load at 10W for the coaxial digital input, sampled at 24/96. We see essentially the same result as with the 16/44.1 FFT above, but with a lower noise floor due to the increased bid depth.

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

Shown above is the FFT for a 1kHz -90dBFS dithered 16/44.1 input sinewave 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, with the second (2kHz) signal harmonic just barely noticeable above the -135dBrA noise floor.

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

Shown above is the FFT for a 1kHz -90dBFS dithered 24/96 input sinewave 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 signal harmonics between -120 and -140dBrA (0.0001-0.00001%).

FFT spectrum – 50Hz (line-level input)

Shown above is the FFT for a 50Hz input sinewave 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 predominant (non-signal) peak is the second (100Hz) signal harmonic at -100dBrA, or 0.001%. Other signal harmonics peaks can be seen at -110dBrA and below.

FFT spectrum – 50Hz (MM phono input)

Shown above is the FFT for a 50Hz input sinewave stimulus measured at the output across an 8-ohm load at 10W for the MM phono input. 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 the 60Hz fundamental power-supply noise peak and its third (180Hz) harmonic at -80/-85dBrA, or 0.01/0.006%. The highest signal harmonic peak is at 100Hz, at -90dBrA, or 0.003%.  

FFT spectrum – 50Hz (MC phono input)

Shown above is the FFT for a 50Hz input sinewave stimulus measured at the output across an 8-ohm load at 10W for the MC phono input. 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 the 60Hz fundamental power-supply noise peak and its third (180Hz) harmonic at -60/-65dBrA, or 0.1/0.06%. The highest signal harmonic is at 100Hz, at -70dBrA, or 0.03%.

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

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 analog line-level input. For this test, 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 -120dBrA, or 0.0001%, while the third-order modulation products, at 17kHz and 20kHz, are at the -95dBrA, or 0.002%, level.

Intermodulation distortion FFT (line-level input, APx 32 tone)

Shown above is the FFT of the speaker-level output of the Majik DSM with the APx 32-tone signal applied to the analog input. The combined amplitude of the 32 tones is the 0dBrA reference and corresponds to 10W into 8 ohms. The intermodulation products—i.e., the “grass” between the test tones—are distortion products from the amplifier and are at and below the -125dBrA level.

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

Shown above is an FFT of the intermodulation distoriton (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 16/44.1 (-1dBFS). We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -120dBrA, or 0.0001%, while the third-order modulation products, at 17kHz and 20kHz, are at the -95dBrA, or 0.002%, level.

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

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 (-1dBFS).We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -120dBrA, or 0.0001%, while the third-order modulation products, at 17kHz and 20kHz, are at the -95dBrA, or 0.002%, level.

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

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 MM phono input. We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -100dBrA, or 0.001%, while the third-order modulation products, at 17kHz and 20kHz, are at -90dBrA, or 0.003%.

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

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 MC phono input. We find that the second-order modulation product (i.e., the difference signal of 1kHz) is at -90dBrA, or 0.003%, while the third-order modulation products, at 17kHz and 20kHz, are at -95dBrA, or 0.002%.

Squarewave 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 Majik DSM’s slew-rate performance. Rather, it should be seen as a qualitative representation of the Majik DSM’s mid-tier bandwidth. An ideal squarewave can be represented as the sum of a sinewave 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. In this case, we find very soft/rounded corners, and the 600kHz oscillator modulating the square wave.

Squarewave response (1kHz)

Above is the 1kHz squarewave response using the analog line-level input, with a 250kHz bandwidth restriction on the analyzer’s inputs to filter out the 600kHz oscillator. Here we see a relatively clean response with some overshoot and ringing in the corners.

FFT spectrum of 400kHz switching frequency relative to a 1kHz tone

The Majik DSM’s amplifier relies on a switching oscillator to convert the input signal to a pulse-width-modulated (PWM) squarewave (on/off) signal before sending the signal through a low-pass filter to generate an output signal. The Majik DSM oscillator switches at a rate of about 600kHz, and this graph plots a wide bandwidth FFT spectrum of the amplifier’s output at 10W into 8 ohms as it’s fed a 1kHz sinewave. We can see that the 600kHz peak is quite evident, and at -35dBrA. There is also a peak at 1.2MHz (the second harmonic of the 600kHz peak), at -70dBrA. Those three peaks—the fundamental and its second harmonic—are direct results of the switching oscillators in the Majik DSM amp modules. The noise around those very-high-frequency signals are in the signal, but all that noise is far above the audioband—and therefore inaudible—and so high in frequency that any loudspeaker the amplifier is driving should filter it all out anyway.

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

The final graph above is the damping factor as a function of frequency. We can see here a constant damping factor of between 100 and 200 up to 2kHz. Beyond this point, there appears to be some sort of active compensation occurring at the outputs (a negative output impedance was measured, which is not possible).

Diego Estan
Electronics Measurement Specialist