Bryston Bi-200 Integrated Amplifier Measurements

Link: reviewed by Philip Beaudette on SoundStage! Hi-Fi on May 1, 2025

General information

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

The Bryston Bi-200 was conditioned for 1 hour at 1/8th full rated power (~25W 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 Bi-200 offers six sets of line-level analog inputs (four unbalanced over RCA, two balanced over XLR), left/right line-level pre-outputs (over RCA and XLR), one set of speaker-level outputs, and a ¼″ TRS headphone output on the front panel. For the purposes of these measurements, the following input was evaluated: balanced analog (XLR) line-level. There were no appreciable differences in terms of THD and noise between the unbalanced and balanced analog inputs. The unbalanced input provides 6dB more gain than the balanced input.

Most measurements were made with a 2Vrms line-level analog input. The signal-to-noise (SNR) measurements were made with the default input signal values but with the volume set to achieve the achievable output power of 200W into 8 ohms. For comparison, on the line-level input, a SNR measurement was also made with the volume at maximum.

Based on the accuracy and randomness of the left/right volume channel matching (see table below), the Bi-200 volume control is digitally controlled but operating in the analog domain. The Bi-200 overall volume range is from -80dB to +34.3dB (balanced line-level input, speaker output). It offers course adjustments from -80dB to -60dB, 2dB increments from -60dB to -51dB, 1dB increments from -51dB to -30dB, and 0.5dB increments from -30dB to 12dB.

Our typical input bandwidth filter setting of 10Hz-22.4kHz was used for all measurements except FFTs and THD versus frequency, where a bandwidth of 10Hz-90kHz was used. Frequency response measurements utilize a DC to 1 MHz input bandwidth.

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 Bryston for the Bi-200 compared directly against our own. The published specifications are sourced from Bryston’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 8 ohms 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 input (unless specified, assume a 1kHz sinewave at 2Vrms, 10W output, 8-ohm loading, 10Hz to 22.4kHz bandwidth):

For the continuous dynamic power test, the Bi-200 was able to sustain 340W into 4 ohms (~2% THD) using an 80Hz tone for 500ms, alternating with a signal at -10dB of the peak (44W) for 5 seconds, for 5 continuous minutes without inducing a fault protection circuit. This test is meant to simulate sporadic dynamic bass peaks in music and movies. During the test, the heatsinks of the Bi-200 were hot to the touch.

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)

In our frequency response plots above (relative to 1kHz), measured across the speaker outputs at 10W into 8 ohms, the Bi-200 is essentially perfectly flat within the audioband (less than -0.1dB at 20Hz). The -3dB point is right around 200kHz. The Bi-200 appears to be AC coupled, yielding roughly -0.8dB at 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 they perfectly overlap, indicating that the two channels are ideally matched.

Phase response (8-ohm loading)

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 Bi-200 yielded just under +10 degrees of phase shift at 20Hz, and less than -20 degrees at 20kHz.

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

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 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 extremely small at roughly 0.03dB below 3-4kHz. This is a strong result and an indication of a very low output impedance, or very high damping factor. With a real speaker load, deviations measured at roughly the same level.

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 194W (just under  the rated output of 200W). The power was varied using the Bi-200’s volume control. All data are fairly closely lumped together, an indication of a strong result for this test. The lowest THD ratios came from the left channel at 194W, around 0.0005% from 100Hz to 1kHz. At these same frequencies, the 1W data yielded the highest THD ratios, but still low at around 0.001%. The same trend of higher THD ratios at high frequencies was observed at all power levels, with THD ratios reaching just above and below the 0.005% level at 20kHz.

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 Bi-200 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). THD ratios into 4 and 8 ohms are close (within roughly 5-8dB). The exception was the left channel into 4 ohms between 25W and 250W, where a THD jump of up to 20dB was observed. The sweep was repeated twice, and the effect was reproducible. For the 8-ohm load, THD ratios ranged from 0.005% at 50mW, down to just above 0.0005% at the “knee” at roughly 200W, then up to the 1% THD mark at 217W. For the 4-ohm load, THD ratios ranged from 0.006% at 50mW, down to 0.001% (right channel) at the “knee” at roughly 250W, then up to the 1% THD mark at 342W.

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 Bi-200 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). THD+N ratios into 4 and 8 ohms are remarkably close (within 3-5dB), with the exception of the left channel into 4 ohms between 25W and 200W. They range from 0.05% at 50mW, down to 0.002-0.003% in the 100 to 200W range.

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 Bi-200 as a function of frequency into three different loads (8/4/2 ohms) for a constant input voltage that yielded 20W at the output into 8 ohms (and roughly 40W into 4 ohms, and 80W 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 data yielded THD ratios roughly 5dB lower than the 4-ohm data, from 0.001% at 20Hz, down to 0.0004% from 100Hz to 1kHz, then up to 0.002% at 20kHz. The 2-ohm data were fairly consistent, at between 0.002% and 0.0003% across the audioband. This is a strong result showing the Bi-200 is stable into low impedance loads.

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 Bi-200 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). Generally, THD ratios into the real speakers were close to those measured across the resistive dummy load. The exception is the two-way speaker from 20Hz to 30Hz, where THD ratios reached 0.02%, roughly 20dB higher than the resistive load. Generally, differences in THD ratios were within the 5dB range, and the results were generally in the 0.0007% to 0.005% range. This is also a very strong result and shows that the Bi-200 is largely speaker load invariant.

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 Bi-200 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, with the three-way speaker yielding 5dB higher results from 4kHz to 20kHz. Generally, the IMD results ranged from 0.001% to 0.005%.

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 Bi-200 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 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). We find very similar IMD ratios into all three loads, between 0.003% and 0.005% across the sweep. Another strong result.

FFT spectrum – 1kHz (line-level XLR 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 balanced input. We see that the signal’s second (2kHz) and third (3kHz) harmonic dominate at roughly -110dBrA, or 0.0003%. There are subsequent signal harmonics visible at roughly -120dBrA, or 0.0001%, and below. On the right side of the signal peak, we find power-supply-related noise peaks (60/120/180/240/300Hz etc) at the -100dBrA, or 0.001%, and below level.

FFT spectrum – 1kHz (line-level RCA 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 unbalanced input. We see effectively the same result as with the balanced input FFT above.

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) peaks are the second (100Hz) and third (150kHz) signal harmonics at roughly -110dBrA, or 0.0003%, and the power-supply-related noise peaks at 120Hz and 240Hz at -100dBrA, or 0.001%.

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. The input RMS values are set at -6.02dBrA so that, if summed for a mean frequency of 18.5kHz, they 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 -110dBrA, or 0.0003%, while the third-order modulation products, at 17kHz and 20kHz are at roughly the same level.

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

Shown above is the FFT of the speaker-level output of the Bi-200 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  -120dBrA, or 0.0001%, level. The other larger peaks are from power-supply-related noise.

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 Bi-200’s slew-rate performance. Rather, it should be seen as a qualitative representation of the Bi-200’s high 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 clean corners with virtually no softening and no over/undershoot.

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

The final graph above is the damping factor as a function of frequency. Both channels track very closely. We can see damping factors ranging from about 600 from 20Hz to 2kHz, then down to just below 200 at 20kHz. This is a very strong result for a solid-state integrated amplifier.

Diego Estan
Electronics Measurement Specialist