How We Test Amplifiers如何测试放大器 [复制链接]

• Measurements were made at 120V AC line voltage with one channel driven (this is a mono amplifier) using the balanced inputs and an Audio Precision AUX-0025 measurement filter unless otherwise noted.
• This amplifier does not invert polarity.
• AC line current draw at idle: 0.26A.
• Input impedance @ 1kHz
  • Balanced input: 8.7k ohms.
  • Unbalanced input: 11.0k ohms.
• Output impedance at 50Hz: 0.008 ohms.
• Gain (8-ohm load): 23.3X, 27.4dB.
• Output noise, 8-ohm load, balanced input, 600-ohm input termination: wideband without A/P AUX-0025 filter 1.29V, -6.8 dBW; wideband 2.07mV, -62.7 dBW; A weighted 0.091 mV, -89.8 dBW.

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 597W
• 8-ohm load at 10% THD: 500W
  
  
• 4-ohm load at 1% THD: 1172W
• 4-ohm load at 10% THD: 1152W

General
The Bel Canto e.One REF1000 is a high-power switching design utilizing the ICEpower 1000ASP module. This marks a departure for Bel Canto, as I believe that their earlier amplifier designs used Tripath circuitry -- quite different from the ICEpower approach.
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 up to about 2-3kHz. Above this, the output impedance has increased to where one can see some variation with load. Above 3kHz, the variation with the NHT dummy speaker load is of the order of perhaps +/-0.4dB. As switching amps go, the ICEpower modules have pretty good high-frequency response control above the audio range with varying loads.
Chart 2 illustrates how total harmonic distortion plus noise vs. power varies for 1kHz and SMPTE IM test signals with 4- and 8-ohm loads. As can be seen, attainable power is greater for the 4-ohm load, as is usual for most power amplifiers. Amount of distortion in Chart 2 is quite reasonable.
Total harmonic distortion plus noise as a function of frequency at several different power levels is plotted in Chart 3. This amplifier does exhibit quite a bit of rise in high-frequency distortion starting below 1kHz. At the higher power levels, it starts to lose it above 10kHz. There is also some rise in distortion at low frequencies.
Damping factor vs. frequency is shown in Chart 4 and is very high at low frequencies but declines precipitously around a few hundred Hz -- not unusual behavior for amplifiers with very high damping factors at low frequencies.
A spectrum of the harmonic distortion and noise residue of a 10W 1kHz test signal is plotted in Chart 5. The amount of AC-line harmonics is admirably low. The signal frequency harmonics are dominantly of odd order.

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

(line up at 10W 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
Green: 900W
Cyan line: 500W
Blue line: 100W
Magenta line: 10W
Red line: 1W

Damping factor = output impedance divided into 8

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

• 测量是在120V交流电压驱动与一个通道（这是一个单声道放大器）使用平衡输入和音频精密辅助- 0025测量滤波器，除非另有说明。
• 该放大器的极性不能倒置。
• 交流线电流消耗在空闲：0.26A。
• @ 1kHz的输入阻抗
  • 平衡输入：8.7k欧姆。
  • 不平衡输入：11.0k欧姆。
• 在50Hz输出阻抗：0.008欧姆。
• 增益（8欧姆负载）：23.3X，二十七点四分贝。
• 输出噪声，8欧姆负载，平衡输入，600欧姆的输入端接：没有的A / P辅助- 0025宽带滤波器1.29V，-6.8无国界医生组织，宽带2.07mV，-62.7无国界医生组织，一个加权0.091 mV时，-89.8无国界医生组织。

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：597W
• 8欧姆负载为10％总谐波失真：500瓦
  
  
• 4欧姆负载，1％总谐波失真：1172W
• 4欧姆负载为10％总谐波失真：1152W

一般
美声唱法e.One REF1000是一种高功率开关设计，利用ICEpower 1000ASP模块。 这标志着美声唱法的离开，因为我相信他们早期的放大器电路设计中使用还在Tripath - 不同于ICEpower方法不同。
图1显示了用不同的负载放大器的频率响应。 可以看出，输出阻抗，作为判断之间开路，8欧姆，4欧姆负荷曲线间距接近，是相当低了约2 - 3kHz。 高于此，输出阻抗已增至这里人们可以看到一些与负荷变化。 以上3kHz，与莱科萨斯虚拟扬声器负载的变化也许是+ / - 0.4dB的秩序。 作为开关放大器去，ICEpower模组有很好的高频率高于音频范围变负荷响应控制。
图2说明了总谐波失真加噪声与功率为1kHz的变化，并与4 SMPTE的即时测试信号 - 和8欧姆的负载。 可以看出，可实现功率为4欧姆负载更大，因为是常见的，最功率放大器。 在图2失真量也相当合理。
总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 该放大器也表现出相当高频率失真低于1kHz时开始上升了一点。 在更高的功率水平，它开始失去它上面10kHz的。 也有一些失真低频率不断上升。
阻尼随频率变化的因素是在图4所示是急剧周围几百赫兹的频率非常低，但跌幅高 - 不寻常行为的放大器在低频率非常高阻尼因素。
阿的谐波失真和10W的1kHz的测试信号噪声频谱残留绘制于图5。 在交流线路的谐波量低令人钦佩。 信号的频率谐波是奇数阶为主。

• Measurements were made at 120V AC line voltage with both channels being driven. Measurements made on the left channel and the unbalanced inputs unless otherwise noted.
• This amplifier does not invert polarity.
• AC line current draw at idle: 0.37A.
• Input impedance @ 1kHz: 9.9k ohms.
• Output impedance at 50Hz: 0.026 ohms.
• Input sensitivity for 1W output into 8 ohms:
  • 1V sensitivity: 99.6mV
  • 2V sensitivity: 197.8mV
• Gain (8-ohm load), unbalanced and balanced inputs:
  • 1V sensitivity: 28.4X, 29.1dB.
  • 2V sensitivity: 14.3X, 23.1dB.
• Output noise, 8-ohm load, unbalanced input, 1k-ohm input termination, Lch/Rch:
  • 1V sensitivity: wideband - 0.21mV, -82.6dBW / 0.18mV, -83.9dBW
  • 2V sensitivity: wideband - 0.18mV, -83.9dBW / 0.13mV, -86.8dBW
  • 1V sensitivity: A weighted - 0.11mV, -88.2dBW / 0.046mV, -95.8dBW
  • 2V sensitivity: A weighted - 0.10mV, -89.0dBW / 0.032mV, -98.9dBW
• Output noise, 8-ohm load, balanced input, 600-ohm input termination, Lch/Rch:
  • 1V sensitivity: wideband - 0.29mV, -79.8dBW / 0.28mV, -80.1dBW
  • 2V sensitivity: wideband - 0.21mV, -82.6dBW / 0.16mV, -85.0dBW
  • 1V sensitivity: A weighted - 0.11mV, -88.2dBW / 0.069mV, -92.3dBW
  • 2V sensitivity: A weighted - 0.10mV, -89.0dBW / 0.040mV, -97.0dBW

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 127W
• 8-ohm load at 10% THD: 163W
  
  
• 4-ohm load at 1% THD: 213W
• 4-ohm load at 10% THD: 235W

General
The Bryston 2B SST C-Series is a medium-power solid-state stereo power amplifier, the lowest-powered unit in Bryston’s SST C-Series line.
Chart 1 shows the frequency response of the amp with varying loads. The high-frequency response is moderately wide with an approximate 3dB down point of 100kHz. Output impedance, as judged by the closeness of spacing between the curves of open-circuit, 8-ohm, and 4-ohm loading, is quite low in the audio band. The usual NHT dummy-load curve is not shown as the variations in the response would not display. The variation with the NHT dummy load in the audio range is of the order of +/-0.05dB -- a negligible amount.
Chart 2 illustrates how total harmonic distortion plus noise vs. power varies for 1kHz and SMPTE IM test signals and amplifier output load. The amount of distortion is low right up to clipping --- the behavior of most solid-state power amplifiers. The distortion performance was essentially identical with unbalanced and balanced connections.
Total harmonic distortion plus noise as a function of frequency at several different power levels is plotted in Chart 3 for 4-ohm loading. The amount of rise in distortion at low and high frequencies is admirably low, except at the 180W level where distortion started to rise abruptly below 20Hz, most likely due to power-supply limitations. This didn’t happen with the 8-ohm loads at the rated 100W power output.
Damping factor vs. frequency is shown in Chart 4 and is of a value and nature typical of many solid-state amplifiers, being high up to about 1kHz and then rolling off with frequency.
The left channel of this unit had somewhat more power-supply line harmonics due to rectifier conduction-pulse ground currents than the quieter right channel. Therefore, the spectrum of both channels is shown in charts 5A and 5B for a 10W 1kHz test signal with 8-ohm loading. As can be seen, the left-channel spectrum has many line harmonics that extend way up into the test-signal area, whereas the right-channel spectrum is more normal looking with low amounts of line harmonics and a tapering-off spectrum of test-signal harmonics.

Red line: open circuit
Magenta line: 8-ohm load
Blue line: 4-ohm load

(line up at 70W to determine lines)
Top line: 4-ohm THD+N
Second line: 8-ohm SMPTE IM
Third line: 8-ohm THD+N
Bottom line: 4-ohm SMPTE IM

4-ohm output loading
Grey line: 180W
Cyan line: 100W
Blue line: 30W
Magenta line: 10W
Red line: 1W

Damping factor = output impedance divided into 8

5A - left channel

1kHz signal at 10W into an 8-ohm load

5B - right channel

1kHz signal at 10W into an 8-ohm load

• 测量是在120V交流线路电压均为驱动渠道。 测量就左声道，除非另有说明，非平衡输入。
• 该放大器的极性不能倒置。
• 交流线电流消耗在空闲：0.37A。
• @ 1kHz的输入阻抗：9.9k欧姆。
• 在50Hz输出阻抗：0.026欧姆。
• 1W的输入灵敏度为8欧姆的输出：
  • 1V的灵敏度：99.6mV
  • 2V的灵敏度：197.8mV
• 增益（8欧姆负载），不平衡和平衡输入：
  • 1V的灵敏度：28.4X，29.1分贝。
  • 2V的灵敏度：14.3X，二十三点一分贝。
• 输出噪声，8欧姆负载，不平衡输入，1K的欧姆输入终端，廖创兴/ Rch的：
  • 1V的灵敏度：宽带 - 0.21mV，- 82.6dBW / 0.18mV，- 83.9dBW
  • 2V的灵敏度：宽带 - 0.18mV，- 83.9dBW / 0.13mV，- 86.8dBW
  • 1V的灵敏度：A加权 - 0.11mV，- 88.2dBW / 0.046mV，- 95.8dBW
  • 2V的灵敏度：A加权 - 0.10mV，- 89.0dBW / 0.032mV，- 98.9dBW
• 输出噪声，8欧姆负载，平衡输入，600欧姆的输入终端，廖创兴/ Rch的：
  • 1V的灵敏度：宽带 - 0.29mV，- 79.8dBW / 0.28mV，- 80.1dBW
  • 2V的灵敏度：宽带 - 0.21mV，- 82.6dBW / 0.16mV，- 85.0dBW
  • 1V的灵敏度：A加权 - 0.11mV，- 88.2dBW / 0.069mV，- 92.3dBW
  • 2V的灵敏度：A加权 - 0.10mV，- 89.0dBW / 0.040mV，- 97.0dBW

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：127W
• 8欧姆负载为10％总谐波失真：163W
  
  
• 4欧姆负载，1％总谐波失真：213W
• 4欧姆负载为10％总谐波失真：235W

一般
海温的Bryston乙C系列是一个中等功率固态立体声功率放大器，在Bryston的海温C系列线最低的供电单位。
图1显示了用不同的负载放大器的频率响应。 高频率响应宽，适度降低100kHz的点近似3dB的。 输出阻抗，如之间开路，8欧姆，4欧姆负荷曲线间距接近判断，是相当低的音频频带。 通常莱科萨斯假负载曲线没有显示如响应不会显示的变化。 与音频范围内的变化是莱科萨斯假负载的+ / -0.05分贝秩序 - 微不足道。
图2说明了总谐波失真加噪声与功率1kHz的测试信号和SMPTE的IM和放大器的输出负载变化。 失真的数量很少直到剪辑---大多数固态功率放大器的行为。 失真的表现基本上是平衡与不平衡和连接相同。
总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示为4欧姆负载。 在低失真和高增长量是令人钦佩的频率低，除了在180瓦水平，失真开始崛起低于20Hz的，最有可能因电力供应的限制。 这并没有发生与在额定100W功率输出的8欧姆负载。
阻尼系数与频率是在图4所示，并与自然的价值，许多固态放大器，典型的是，被高至约1kHz的频率，然后滚动关闭。
该单位的左声道有较为电源线由于整流谐波比安静的右声道传导电流脉冲地面。 因此，这两个频道频谱显示在图表5A和5B 1kHz时为10W的8欧姆负载试验信号。 可以看出，左边的通道频谱谐波，有许多行一路延伸到测试信号区，而右声道是比较正常的频谱与低量的线路谐波​​和逐渐减少的测试过的频谱看，信号的谐波。

• Measurements were made with 120V AC line voltage with both channels driven, input gain switch set to 1V, driving the unbalanced inputs unless otherwise noted.
• Gain, unbalanced input: 28.7x, 29.5dB (with input switch set to 1V)
• Output noise, 8-ohm load, unbalanced input, 1k-ohm input termination: wideband 0.260mV, -80.7dBW; A weighted 0.067mV, -92.5dBW.
• Output noise, 8-ohm load, balanced input, 600-ohm input termination: wideband 0.307mV, -79.3dBW; A weighted 0.083mV, -90.6dBW.
• AC line current draw at idle: 1.0A.
• Output impedance at 50Hz: 0.011 ohms.
• This amplifier does not invert polarity.

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 336W
  
  
• 4-ohm load at 1% THD: 528W

General
The Bryston 4B SST 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 modest -- a good thing. Damping factor versus frequency is shown in Chart 4. A spectrum of the harmonic distortion and noise residue is plotted in Chart 5. The magnitude of the AC line harmonics are low for this amplifier. 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
Cyan line: 8-ohm load
Blue line: 4-ohm load
Magenta line: NHT dummy-speaker load

(line up at 10W 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: 450W
Blue line: 140W
Magenta line: 20W
Red line: 2W

Damping factor = output impedance divided into 8

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

• 测量120V交流会上提出了既驱动通道，输入增益线路电压开关设置为1V，推动非平衡输入，除非另有说明。
• 增益，不平衡输入：28.7x，二十九点五分贝（与输入开关设定到1V）
• 输出噪声，8欧姆负载，不平衡输入，1K的欧姆输入终端：宽带0.260mV，- 80.7dBW，一个加权0.067mV，- 92.5dBW。
• 输出噪声，8欧姆负载，平衡输入，600欧姆的输入端接：宽带0.307mV，- 79.3dBW，一个加权0.083mV，- 90.6dBW。
• AC线在空闲电流消耗：1.0A的。
• 在50Hz输出阻抗：0.011欧姆。
• 该放大器的极性不能倒置。

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：336W
  
  
• 4欧姆负载，1％总谐波失真：528W

一般
海温的Bryston 4B条是medium-/high-power固态与典型宽的带宽和非常低的输出阻抗设计。
图1显示了用不同的负载放大器的频率响应。 可以看出，输出阻抗，作为判断之间开路，8欧姆，4欧姆负荷曲线间距接近是相当低的。 与音频范围内的莱科萨斯假负载的变化可以忽略不计。 图2说明了总谐波失真加噪声功率比和SMPTE即时1kHz的测试信号和放大器的输出负载变化。 可以看出，可实现功率为4欧姆负载更大，因为是常见的，最功率放大器。总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 在高频率的增加量是适度的变形 - 一件好事。 阻尼频率因子与图4所示。 阿的谐波失真和噪声残留谱绘制于图5。 交流线路的谐波幅度较低这个放大器。 测试信号谐波都是奇数和偶数的总和占据了总谐波谐波的奇次谐波。 在高次谐波迅速下降到噪音水平。

• Measurements were made at 120V AC line voltage with both channels being driven; measurements made on left channel unless otherwise noted.
• This integrated amplifier does not invert polarity.
• AC line current draw:
  • at idle: 0.76A
  • in standby: 0.00A
• Input sensitivity for 1W output into 8 ohms, volume at maximum: 24.8mV
• Input impedance @ 1kHz: 47.6k ohms
• Output impedance at 50Hz: 0.026 ohms
• Gain, output voltage divided by input voltage, volume at maximum: 114.2X, 41.2dB
• Output noise, 8-ohm load, 1k-ohm input termination, Lch/Rch
  • Volume control at reference position
    • wideband: 0.70mV, -72.1dBW / 0.66mV, -72.6dBW
    • A weighted: 0.37mV, -77.7dBW / 0.33mV, -78.7dBW
  • Volume control full clockwise
    • wideband: 1.86mV, -63.6dBW / 1.84mV, -63.7dBW
    • A weighted: 0.67mV, -72.5dBW / 0.65mV, -72.8dBW
  • Volume control full counterclockwise
    • wideband: 0.63mV, -73.0dBW / 0.59mV, -73.6dBW
    • A weighted: 0.36mV, -77.9dBW / 0.32mV, -78.9dBW

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 140W
• 8-ohm load at 10% THD: 165W
  
  
• 4-ohm load at 1% THD: 191W
• 4-ohm load at 10% THD: 213W

General
The Bryston B100 SST is a medium-power solid-state integrated amplifier. The overall gain of this unit is on the high side for an integrated amplifier of the type so popular these days -- the kind with a passive selector switch and volume control preceding a power amplifier. The B100 SST has an active line-level preamp stage within, and the overall gain is appropriate for this topology.
Chart 1 shows the frequency response of the amp with varying loads. The high-frequency response is moderately wide with an approximate -3dB point of 80kHz. Output impedance, as judged by the closeness of spacing between the curves of open-circuit, 8-ohm and 4-ohm loading, is quite low in the audio band. The usual NHT-dummy-load curve is not shown as the variations in the response would not appear. The variation with the NHT dummy load in the audio range is less than +/-0.05dB -- a negligible amount. The frequency response was quite independent of volume-control setting. This plot was made with the reference volume-control position as set for 0.5V input to produce 5W output into an 8-ohm load.
Chart 2 illustrates how total harmonic distortion plus noise vs. power varies for 1kHz and SMPTE IM test signals and amplifier output load. Amount of distortion is satisfactorily low in this design, rising out of the noise at 10-20W.
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 admirably low -- practically non-existent.
Damping factor vs. frequency is shown in Chart 4 and is of a value and nature typical of many solid-state amplifiers, being high up to mid-hundreds of Hz and then rolling off with frequency.
A spectrum of the harmonic distortion and noise residue of a 10W 1kHz test signal is plotted in Chart 5. The magnitudes of the AC-line harmonics are low and simple, and intermodulation components of line harmonics with signal harmonics are also low. Visible signal harmonics consist of second, third, and fourth harmonics.

Red line: open circuit
Magenta line: 8-ohm load
Blue line: 4-ohm load

(line up at 50W to determine lines)
Top line: 8-ohm SMPTE IM
Second line: 4-ohm SMPTE IM
Third line: 8-ohm THD+N
Bottom line: 4-ohm THD+N

8-ohm output loading
Cyan line: 100W
Blue line: 30W
Magenta line: 10W
Red line: 1W

Damping factor = output impedance divided into 8

1kHz signal at 10W into an 8-ohm load

• 测量是在120V交流线路电压均为驱动渠道;在左声道，除非另有说明进行的测量。
• 这种集成放大器的极性不能倒置。
• 交流线路电流：
  • 在怠速：0.76A
  • 在待机状态：0.00A
• 1W输出的输入灵敏度为8欧姆，音量开到最大：24.8mV
• @ 1kHz的输入阻抗：47.6k欧姆
• 在50Hz输出阻抗：0.026欧姆
• 增益，输出电压的输入电压，在最大音量分为：114.2X，41.2分贝
• 输出噪声，8欧姆负载，1K的欧姆输入终端，廖创兴/ Rch的
  • 音量控制在基准位置
    • 宽带：0.70mV，- 72.1dBW / 0.66mV，- 72.6dBW
    • A加权：0.37mV，- 77.7dBW / 0.33mV，- 78.7dBW
  • 音量控制旋钮顺时针满
    • 宽带：1.86mV，- 63.6dBW / 1.84mV，- 63.7dBW
    • A加权：0.67mV，- 72.5dBW / 0.65mV，- 72.8dBW
  • 音量控制逆时针
    • 宽带：0.63mV，- 73.0dBW / 0.59mV，- 73.6dBW
    • A加权：0.36mV，- 77.9dBW / 0.32mV，- 78.9dBW

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：140W的
• 8欧姆负载为10％总谐波失真：165瓦
  
  
• 4欧姆负载，1％总谐波失真：191W
• 4欧姆负载为10％总谐波失真：213W

一般
B100的海表温度的Bryston是一个中等功率固态放大器集成。 该单位的总增益为一个类型受追捧集成放大器偏高 - 与被动选择开关和音量控制功率放大器前一种。 在B100的海温有一个活跃的线路级前置阶段内，整体增益这种拓扑结构是适当的。
图1显示了用不同的负载放大器的频率响应。 高频率响应宽适度的80kHz的近似- 3dB点。输出阻抗，如之间开路，8欧姆和4欧姆负荷曲线间距接近判断，是相当低的音频频带。 通常莱科萨斯-假负载曲线不作为的反应将不会出现变化。 与音频范围内的莱科萨斯假负载变化小于+ / -0.05分贝 - 一个微不足道的金额。 频率的反应相当的音量控制设置无关。 此图写了与参考音量控制位​​置为0.5V的输入，以产生为8欧姆负载5W输出设置。
图2说明了总谐波失真加噪声与功率1kHz的测试信号和SMPTE的IM和放大器的输出负载变化。 令人满意的是低失真量在这个设计中，上升为10 - 20W的噪音。
总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 在高频率的增加额是令人钦佩的失真低 - 几乎不存在。
阻尼系数与频率显示在图4和第一个值和性质许多固态放大器典型的是，被高至中期的数百赫兹的频率，然后滚动关闭。
阿的谐波失真和10W的1kHz的测试信号噪声频谱残留绘制于图5。 在交流线路谐波的幅度线谐波低，简单，和互调分量信号谐波也较低。 可见信号谐波组成的第二，第三和第四谐波。

• 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

• 测量是用120V交流与使用非平衡输入驱动两个通道的线路电压。
• 增益，非平衡输入/平衡输入：28.6x，29.1dB/28.6x，29.1分贝。
• 输出噪声，8欧姆负载，不平衡输入，1K的欧姆输入终端：宽带0.282mV，- 80.0dBW，一个加权0.068mV，- 92.4dBW。
• 输出噪声，8欧姆负载，平衡输入，600欧姆的输入端接：宽带0.285mV，- 79.9dBW，一个加权0.065mV，- 92.8dBW。
• 交流线电流消耗在空闲：1.44A。
• 在50Hz输出阻抗：0.0055欧姆。
• 该放大器的极性不能倒置。

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：224W
  
  
• 4欧姆负载，1％总谐波失真：425W

一般
该Classé音频的CA - 2200是一种medium-/high-power固态与一般宽的带宽和非常低的输出阻抗设计。
图1显示了用不同的负载放大器的频率响应。 可以看出，输出阻抗，作为判断之间开路，8欧姆，4欧姆负荷曲线间距接近，是相当低的。 与音频范围内的莱科萨斯假负载的变化可以忽略不计。
图2说明了总谐波失真加噪声功率比和SMPTE即时1kHz的测试信号和放大器的输出负载变化。 可以看出，可实现功率为4欧姆负载更大，因为是常见的，最功率放大器。
总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 在高频率的失真上升的数量也相当明显，是许多类似的测量放大器的。
阻尼频率因子与图4所示，是非常高。
阿的谐波失真和噪声残留谱绘制于图5。 将AC -线路谐波幅度很低，在实验室测量放大器的BHK许多典型。 测试信号谐波都是偶次谐波，总谐波与主宰奇次谐波的总和。 在高次谐波迅速下降到噪音水平。

• Measurements were made with 120V AC line voltage.
• Power output and distortion plotted with both channels driven.
• Test signal applied to unbalanced inputs unless otherwise noted.
• Output noise, 8-ohm load, unbalanced input, 1k-ohm input termination: wideband 0.429mV, -76.4dBW; A weighted 0.108mV, -88.4dBW.
• Output noise, 8-ohm load, balanced input, 600-ohm input termination: wideband 0.239mV, -81.5dBW; A weighted 0.113mV, -88.0dBW.
• AC line current draw at idle: 3.7A cold, 1.8A warmed up.
• Output impedance at 50Hz: 0.052 ohms.
• This amplifier does not invert polarity.

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 142W
  
  
• 4-ohm load at 1% THD: 246W

General
The Coda Model 12 is a high-power solid-state design with very low output impedance and a relatively high output-stage idling current. As far as the front-panel designation of "Class A," this is most decidedly not the case. A true classic standard definition class-A amplifier at this power level would draw some 10A off the AC line to be class A up to clipping with 8-ohm loads. Unusually, the low output impedance extends way up into the ultrasonic frequency measurement limit of my Audio Precision measurement system.
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 very low. The variation with the NHT dummy load would be about a neglible +/-0.05dB. Note that the curves track each other above the audio range, indicating the output impedance is low in this region also. 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. This amp is one of a very few in my experience that has the desirable characteristic of approximately constant amount of distortion versus frequency. Damping factor versus frequency is shown in Chart 4. Note how this is quite constant over the audio range. A spectrum of the harmonic distortion and noise residue is plotted in Chart 5. As seems to be the case with many amplifiers measured, this one has a rich series of AC-line-hum harmonics with some sidebands of these harmonics about the nulled fundamental frequency and the signal harmonics. Of note: the amount of signal harmonics are low and the higher-order products disappear rapidly.

Magenta line: open circuit
Red line: 8-ohm load
Blue line: 4-ohm load

(line up at 10W 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
Red line: 2W
Magenta line: 20W
Blue line: 120W
Cyan line: 220W

Damping factor = output impedance divided into 8

1kHz signal at 10W into an 8-ohm load

• 测量是用120V交流电压。
• 输出功率和失真策划既带动渠道。
• 测试信号施加到非平衡输入，除非另有说明。
• 输出噪声，8欧姆负载，不平衡输入，1K的欧姆输入终端：宽带0.429mV，- 76.4dBW，一个加权0.108mV，- 88.4dBW。
• 输出噪声，8欧姆负载，平衡输入，600欧姆的输入端接：宽带0.239mV，- 81.5dBW，一个加权0.113mV，- 88.0dBW。
• AC线在闲置电流：3.7A冷，1.8A热身。
• 在50Hz输出阻抗：0.052欧姆。
• 该放大器的极性不能倒置。

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：142W
  
  
• 4欧姆负载，1％总谐波失真：246W

一般
12的尾波模型是一种高功率固体状态非常低的输出阻抗和相对高的输出级空载电流设计。至于前面板指定的“A级”，这是最坚决并非如此。 一个真正的经典标准清晰度甲级此功率级放大器交流会抽出一些10A条线是A级到8欧姆负载裁剪。 与众不同的是，低输出阻抗一路延伸到我的超声波频率的音频精密测量系统的测量极限。
图1显示了用不同的负载放大器的频率响应。 可以看出，输出阻抗，作为判断之间开路，8欧姆，4欧姆负荷曲线间距接近很低。 用假负载变化莱科萨斯将约为微不足道+ / -0.05分贝。 请注意，上面的曲线轨道相互音频范围，显示，输出阻抗是在这一地区还低。 图2说明了总谐波失真加噪声功率比和SMPTE即时1kHz的测试信号和放大器的输出负载变化。可以看出，可实现功率为4欧姆负载更大，因为是常见的，最功率放大器。 总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 这种放大器是一个非常在我的经验，具有大致相同的金额与频率失真为数不多的理想特性。 阻尼频率因子与图4所示。 请注意这是相当多的音频范围不变。 阿的谐波失真和噪声残留谱绘制于图5。 似乎是由于与实测许多放大器的情况下，这其中有一个关于清零与基频和谐波这些谐波信号边带一些交流线路哼谐波丰富系列。 值得注意的是：信号谐波量低，较高阶的产品迅速消失。

• Measurements were made with 120V AC line voltage.
• Measurements were made on the left channel.
• Gain: 24.6x, 27.8dB.
• Output noise, 8-ohm load, unbalanced input, 1k-ohm input termination: wideband 0.255mV, -80.9dBW; A weighted 0.103mV, -88.8dBW.
• AC line current draw at idle: 3.6A.
• Output impedance at 50Hz: 0.98 ohms.
• This amplifier does not invert polarity.

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 98W
• 8-ohm load at 10% THD: 110W
  
  
• 4-ohm load at 1% THD: 140W
• 4-ohm load at 10% THD: 160W

General
The Conrad-Johnson Premier 140 tube amp is an interesting-looking piece. Its physical layout is unusual in that the front and rear panels are on the sides relative to the enclosed transformer and capacitor cover. This amp is a stereo push-pull design rated at a nominal 140W. A potentiometer and LED indicator set output-tube idling current adjacent to each output tube.
High-frequency bandwith, as seen in Chart 1, is unusually wide for a tube design having a 3dB down point of about 140kHz. The low-frequency response holds up down to 10Hz nicely at the 1W level of the test. utput impedance is typical of many tube amplifiers, giving less than a 2dB frequency-response variation with the NHT dummy speaker load. Total harmonic distortion plus noise and SMPTE IM distortion as a function of power output and load for a test frequency of 1kHz is plotted in Chart 2. More power is delivered with the 4-ohm load as that is the default way the amp is delivered. (The amp can be configured to be optimum for 8- or 16-ohm loads.) Amount of distortion is admirably low for powers up to perhaps 10-20W, where the kernel of most music resides. Total harmonic distortion plus noise as a function of frequency at several power levels is plotted in Chart 3 for a 4-ohm load. Admirable is the relatively low amount of distortion increase at the higher frequencies. However, distortion does rise considerably below 20Hz at higher powers. The rise in distortion at low frequencies is a strong function of how closely the bias is adjusted for equal current in all four output tubes. When I first measured the left channel of this amp, the rise in distortion at low frequencies was considerably more pronounced. When I went to more carefully adjust the bias, I found that two of the four output tubes were down in current compared to the other two. When I really tweaked the bias so that the red indicator LEDs just went out at 120V AC line input for all four tubes, the performance of the left channel more closely matched that of the right channel. Damping factor vs. frequency referred to an 8-ohm load is plotted in Chart 4, and it is quite consistent over most of the audio range. In the spectral plot of distortion and noise for a 10W 1kHz signal into a 4-ohm load plotted in Chart 5, the signal distortion components are dominated by the second and third harmonics with higher-order harmonics at reduced and decreasing amplitude with frequency. As I have seen in quite a number of other amplifiers measured, there is quite a bit of 120Hz power-supply hum modulation around the suppressed fundamental 1-kHz test frequency.

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

(line up at 10W to determine lines)
Top line: 8-ohm SMPTE IM
Second line: 4-ohm SMPTE IM
Third line: 4-ohm THD+N
Bottom line: 8-ohm THD+N

4-ohm output loading
Green line: 140W
Blue line: 30W
Magenta line: 10W
Red line: 1W

Damping factor = output impedance divided into 8

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

• 测量是用120V交流电压。
• 测量了左侧通道。
• 增益：24.6x，二十七点八分贝。
• 输出噪声，8欧姆负载，不平衡输入，1K的欧姆输入终端：宽带0.255mV，- 80.9dBW，一个加权0.103mV，- 88.8dBW。
• AC线在空闲电流消耗：3.6A。
• 在50Hz输出阻抗：0.98欧姆。
• 该放大器的极性不能倒置。

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：98W
• 8欧姆负载为10％总谐波失真：110W
  
  
• 4欧姆负载，1％总谐波失真：140W的
• 4欧姆负载为10％总谐波失真：160瓦

一般
康拉德- 140电子管功放约翰逊总理是一个有趣的外观件。 它的物理布局是与众不同的，前后面板的两侧相对封闭的变压器和电容器盖的。 这是一个立体声放大器推挽设计在额定标称140W的。 电位器和LED指示灯设置输出管相邻的空载电流输出管。
高频带宽，如图表1所示，是一个不同寻常的宽管有3dB的下降点约140kHz设计。 低频响应容纳到在10Hz的试验1W的水平很好。 utput阻抗是许多管放大器的典型，使超过2dB的频率响应与莱科萨斯虚拟扬声器负载变化少。 总谐波失真加一个功能，输出功率为1kHz的测试频率负载噪音和SMPTE的IM失真是绘制于图2。 更多的功率传递与4欧姆负载因为这是默认方式，AMP被交付。 （该放大器可以配置为8最佳 - 。或16欧姆负载）的低失真量，是令人钦佩的权力，直至大约10 - 20W的，那里的大多数音乐的核心所在。 总谐波失真加作为频率的函数噪声功率水平在几个图3所示为一个4欧姆负载。 令人钦佩的是在较高的变形频率的增加量相对较低。 然而，不失真点起床，更高的权力大大低于20Hz的。 在低频失真的崛起是如何紧密合作，平等的偏见是当前调整，在所有四个输出管的强大功能。 当我第一次测出这功放左声道，在低频失真大大上升更为显着。 当我去更仔细地调整偏见，我发现，四个输出管二下跌目前相对于其他两个。 当我真的调整了偏差，使红色LED指示灯就一直在120V交流输入线为所有四个管，左声道的表现更密切配合，该权利的渠道。 阻尼系数与频率提到了8欧姆负载绘制于图4，这是相当一致的音频范围以上的多数。 在失真和噪声1kHz时为10W的为4欧姆负载信号的频谱图绘于图5，信号失真组件由高次谐波的二次和三次谐波主宰随频率降低，降低幅度。 正如我在其他相当多的测量放大器的数目来看，有相当多的120Hz的电源位哼调制抑制各地的基本1 kHz的测试频率。

• Measurements were made at 120V AC line voltage with both channels driven.
• This amplifier inverts polarity.
• AC line current draw
  • Plugged in: 0.02A
  • At idle: 1.65A
• Input impedance @ 1kHz: 80k ohms.
• Output impedance at 50Hz: 0.12 ohms.
• Gain (8-ohm load): 54.8X, 34.8dB.
• Output noise, 8-ohm load, 1k-ohm input termination, Lch/Rch:
  • Wideband: 0.295mV, -79.6dBW / 0.465mV, -75.7dBW
  • A weighted: 0.112mV, -88.0dBW / 0.177mV, -84.0dBW

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 400W
• 8-ohm load at 10% THD: 500W
  
  
• 4-ohm load at 1% THD: 640W
• 4-ohm load at 10% THD: 800W

General
The Conrad-Johnson Premier 350 is a high-power solid-state design with wide bandwidth and low output impedance typical of solid-state power amplifiers. It has a complementary MOSFET first stage that provides all the voltage gain of the circuit. The output stage is a complementary bi-polar compound gain of one circuit with MOSFET drivers. No overall signal feedback is used, although DC feedback is employed to help keep the output-offset DC voltage low.
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 (not shown as it won’t show up in the chart) in the audio range is of the order of +/- 0.1dB.
Chart 2 illustrates how total harmonic distortion plus noise vs. 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 admirably low in this design.
Damping factor vs. frequency is shown in Chart 4 and is reasonably constant with frequency.
A spectrum of the harmonic distortion and noise residue of a 10W 1kHz test signal is plotted in Chart 5. The magnitude of the AC-line harmonics is typical of many power amplifiers measured. The principal signal harmonics are of odd order with some low-level higher-order components.

Red line: open circuit
Magenta line: 8-ohm load
Blue line: 4-ohm load

(line up at 10W 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

8-ohm output loading
Cyan line: 350W
Blue line: 70W
Magenta line: 10W
Red line: 1W

Damping factor = output impedance divided into 8

1kHz signal at 10W into an 8-ohm load

• 测量是在120V交流电压既带动渠道。
• 该放大器颠倒极性。
• 交流线电流
  • 插入：0.02A
  • 在怠速：1.65A
• @ 1kHz的输入阻抗：80,000欧姆。
• 在50Hz输出阻抗：0.12欧姆。
• 增益（8欧姆负载）：54.8X，三十四点八分贝。
• 输出噪声，8欧姆负载，1K的欧姆输入终端，廖创兴/ Rch的：
  • 宽带：0.295mV，- 79.6dBW / 0.465mV，- 75.7dBW
  • A加权：0.112mV，- 88.0dBW / 0.177mV，- 84.0dBW

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：400W的
• 8欧姆负载为10％总谐波失真：500瓦
  
  
• 4欧姆负载，1％总谐波失真：640W
• 4欧姆负载为10％总谐波失真：800W的

一般
康拉德-约翰逊总理350是高功率固体状态的宽带宽和低输出阻抗的固态功率放大器的典型设计。 它有一个互补型MOSFET的第一阶段提供所有电路的电压增益。 输出级是一个互补双极一个电路和MOSFET驱动器的复合收益。 没有整体的信号反馈使用，虽然采用直流反馈，以帮助保持输出直流偏移电压低。
图1显示了用不同的负载放大器的频率响应。 可以看出，输出阻抗，作为判断之间开路，8欧姆，4欧姆负荷曲线间距接近，是相当低的。 与莱科萨斯假负载音频范围内（不显示，因为它不会显示在图表上）的变化，是秩序+ / - 0.1dB的。
图2说明了总谐波失真加噪声与功率1kHz的测试信号和SMPTE的IM和放大器的输出负载变化。 可以看出，可实现功率为4欧姆负载更大，因为是常见的，最功率放大器。
总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 在高频率的增加额是令人钦佩的失真低，这个设计。
阻尼随频率变化的因素是显示在图4及合理与频率的关系。
阿的谐波失真和10W的1kHz的测试信号噪声频谱残留绘制于图5。 将AC -线路谐波幅度是许多电力测量放大器的典型。 主要信号谐波都用一些低层次的高阶元件奇数阶。

• Measurements were made at 120V AC line voltage with both channels being driven.
• Measurements made on left channel unless otherwise noted.
• Input sensitivity for 1W output into 8 ohms: 12.1mV
• Gain, output voltage divided by input voltage, volume at maximum: 233.6X, 47.4dB
• Output noise, 8-ohm load, unbalanced input, 1k-ohm input termination: wideband 1.46mV, -65.7dBW; A weighted 0.367mV, -77.7dBW.
• AC line current draw at idle: 1.2A.
• Output impedance at 50Hz: 1.6 ohms.
• This integrated amplifier inverts polarity.

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 22.0W
• 8-ohm load at 10% THD: 35.7W
  
  
• 4-ohm load at 1% THD: 21.0W
• 4-ohm load at 10% THD: 25.0W

General
The CR Developments Romulus is a low-/medium-power integrated tube amplifier utilizing a pair of 6L6WGC output tubes in each channel. Gain of the unit is somewhat higher than necessary for typical line-level sources that will likely cause the volume control to be turned way down for normal listening levels.
Chart 1 shows the frequency response of the amp with varying loads. The high-frequency response is not very extended in this design as the 3dB down point is about 20kHz. 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 of a typical value for tube amplifiers. The variation with the NHT dummy load in the audio range is of the order of +1/-3dB. The frequency response was quite independent of volume-control setting. This plot was made with the reference volume control position as set for 0.5V input to produce 5W output into an 8-ohm load.
Chart 2 illustrates how total harmonic distortion plus noise vs. power varies for 1kHz and SMPTE IM test signals and amplifier output load. This design, with its single output connection for speaker loads, is more optimized for 8 ohms rather than 4 ohms. As can be seen, the power attainable is greater for 8-ohm loading for a given distortion amount.
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 low and high frequencies is reasonable for a modest-powered integrated amplifier such as the Romulus. The distortion falls off above 10kHz because of the amplifier’s limited high-frequency bandwidth.
Damping factor vs. frequency is shown in Chart 4 and is of a value typical of many tube amplifiers.
A spectrum of the harmonic distortion and noise residue of a 10W 1kHz test signal is plotted in Chart 5. The magnitude of the AC-line harmonics are quite numerous and intermodulation components of line harmonics with signal harmonics are also very numerous and visible. Indicative of good push-pull balance, the test-signal harmonics are dominantly odd order and tail off fairly rapidly with frequency.

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

(line up at 5W 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

8-ohm output loading
Cyan line: 30W
Blue line: 10W
Magenta line: 5W
Red line: 2W

Damping factor = output impedance divided into 8

1kHz signal at 10W into a 8-ohm load

• 测量是在120V交流线路电压均为驱动渠道。
• 测量就左声道，除非另有说明。
• 1W输出的输入灵敏度为8欧姆：12.1mV
• 增益，输出电压的输入电压，在最大音量分为：233.6X，四十七点四分贝
• 输出噪声，8欧姆负载，不平衡输入，1K的欧姆输入终端：宽带1.46mV，- 65.7dBW，一个加权0.367mV，- 77.7dBW。
• AC线在空闲电流消耗：1.2A的。
• 在50Hz输出阻抗：1.6欧姆。
• 这种集成放大器颠倒极性。

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：22.0W
• 8欧姆负载为10％总谐波失真：35.7W
  
  
• 4欧姆负载，1％总谐波失真：21.0W
• 4欧姆负载为10％总谐波失真：25.0W

一般
公司注册处的发展罗穆卢斯是low-/medium-power利用综合管放大器输出管的6L6WGC每个通道对。 单位增益略低于典型线路信号源，这将可能导致被打开音量控制为正常听力水平的方法而需要更高。
图1显示了用不同的负载放大器的频率响应。 高频率响应不是很延长这项工作作为3dB的设计上下点是20kHz的。 可以看出，输出阻抗，如之间开路，8欧姆，4欧姆负荷曲线间距接近判断，是一个管放大器的典型值。 与音频范围内的莱科萨斯假负载变化的1 / - 3dB的秩序。 频率的反应相当的音量控制设置无关。 此图是作出的参考音量控制位​​置为输入，以产生0.5V的为8欧姆负载5W输出设置。
图2说明了总谐波失真加噪声与功率1kHz的测试信号和SMPTE的IM和放大器的输出负载变化。 这与它的扬声器负载单输出接口设计，更优化的8欧姆，而不是4欧姆。 可以看出，功率可以达到为8欧姆的负荷更大的一个给定的失真量。
总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 崛起中的低失真和高频率的金额是合理的，温和的动力，如罗穆卢斯集成放大器。 上面的变形脱落，因为放大器的有限高频10kHz的带宽。
阻尼随频率变化的因素是显示在图4和第一个值，许多典型的就是管放大器。
阿的谐波失真和10W的1kHz的测试信号噪声频谱残留绘制于图5。 将AC -线路谐波幅度是相当众多线路谐波和互调分量信号谐波也非常多，而且可见。 良好的推拉平衡的指示，测试信号的谐波为主奇数阶和尾关闭较快频率。

• Measurements were made with 120V AC line voltage with both channels driven, driving the unbalanced inputs unless otherwise noted.
• Gain: 20x, 26dB.
• Output noise, 8-ohm load, unbalanced input, 1k-ohm input termination: wideband 0.602mV, -73.4dBW; A weighted 0.062mV, -93.2dBW.
• Output noise, 8-ohm load, balanced input, 600-ohm input termination: wideband *6.41mV, -52.9dBW; A weighted 0.088mV, -90.1dBW. (* There was a small amount of approximately 90kHz low-level spurious signal in the left channel that the manufacturer indicates that some units do exhibit and is deemed harmless to the sound.)
• AC line current draw at idle: 1.3A.
• Output impedance at 50Hz: 0.29 ohms.
• This amplifier does not invert polarity.

Power output with 1kHz test signal

• 8-ohm load at 1% THD: 142W
  
  
• 4-ohm load at 1% THD: 158W

General
The darTZeel NHB-108 is a medium-power solid-state design with typically wide bandwidth and output impedance a bit higher than is usual for solid-state amplifiers. Some of its measured characteristics are similar to those of a tube amplifier, such as relatively high measured distortion and a modest damping factor. Both are suggestive of little or no overall negative feedback in the design.
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 of the order of +/-0.25 dB.
Chart 2 illustrates how total harmonic distortion plus noise vs. 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. Amount of distortion is relatively high for solid-state designs, but the way the amp goes into clipping is more like a typical solid-state amplifier.
Total harmonic distortion plus noise as a function of frequency at several different power levels is plotted in Chart 3. Interestingly, the distortion amount vs. frequency for the lower powers is virtually constant, whereas at higher powers the distortion does rise a bit at the high end of the audio band.
Damping factor vs. frequency is shown in Chart 4, and is moderate but reasonably constant with frequency, again not usual for solid-state designs.
A spectrum of the harmonic distortion and noise residue of a 10W 1kHz test signal is plotted in Chart 5. The magnitude of the AC-line harmonics is quite numerous and intermodulation components of line harmonics with signal harmonics are also just visible near the noise floor. The test signal harmonics are both even and odd and don't decline or tail-off with frequency very fast.

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

(line up at 10W 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

8-ohm output loading
Cyan line: 100W
Blue line: 40W
Magenta line: 10W
Red line: 1W

Damping factor = output impedance divided into 8

1kHz signal at 10W into an 8-ohm load

• 测量了既与120V交流线路电压驱动渠道，推动非平衡输入，除非另有说明。
• 增益：20倍，为26dB。
• 输出噪声，8欧姆负载，不平衡输入，1K的欧姆输入终端：宽带0.602mV，- 73.4dBW，一个加权0.062mV，- 93.2dBW。
• 输出噪声，8欧姆负载，平衡输入，600欧姆的输入端接：宽带* 6.41mV，- 52.9dBW，一个加权0.088mV，- 90.1dBW。 （*有一个约90kHz低级别的杂散信号少量左声道的制造商表示，一些单位做展出，被认为是无害的声音。）
• 交流线电流消耗在空闲：1.3a的。
• 在50Hz输出阻抗：0.29欧姆。
• 该放大器的极性不能倒置。

功率输出1kHz的测试信号

• 8欧姆负载，1％总谐波失真：142W
  
  
• 4欧姆负载，1％总谐波失真：158W

一般
总健康效益的darTZeel - 108是一种中等功率固体状态与一般宽的带宽和输出阻抗高一点，比固态放大器通常的设计。 其测量的特点有些类似，一个管放大器等相对高的测量失真和适度阻尼因子。 两者都是很少或根本没有整体的设计负反馈暗示。
图1显示了用不同的负载放大器的频率响应。 可以看出，输出阻抗，作为判断之间开路，8欧姆，4欧姆负荷曲线间距接近，是相当低的。 与音频范围内的莱科萨斯假负载的变化，是秩序+ / -0.25分贝。
图2说明了总谐波失真加噪声与功率1kHz的测试信号和SMPTE的IM和放大器的输出负载变化。 可以看出，可实现功率为4欧姆负载更大，因为是常见的，最功率放大器。 变形量相对固态设计的高，但这样的放大器去剪裁成更像是一个典型的固态放大器。
总谐波失真加作为频率的函数噪声功率水平在几个不同的是在图3所示。 有趣的是，主场迎战权力的较低频率的失真量几乎不变，而在更高的权力，扭曲并增加在音频频带高端一点。
阻尼随频率变化的因素是在图4所示，是温和的，但合理的频率不变，又不是固态设计如常。
阿的谐波失真和10W的1kHz的测试信号噪声频谱残留绘制于图5。 将AC -线路谐波幅度相当众多的线路谐波​​和互调分量信号谐波也只是接近本底噪声可见。 测试信号谐波都是偶数和奇数和尾下降或不小康，频率非常快。