PAA Audio American FET v1.1.1 [WiN]

MOCHA | 21 October 2026 | 6.7 MB

American FET | 这款 500 系列 FET 压缩器为美国唱片注入了活力。

* 出厂前，每一台设备都经过工厂严格测试。读数固定，合格或不合格。American FET 也经过同样的校准，在压缩和限制模式下，所有六个电平读数均达到标准。
* 先试听，再决定是否购买。下方：同一录音，分别测试插件开启和关闭两种模式的效果，电平匹配，确保音量大小一致。您可以切换测试结果，自行选择。
* 一个旋钮即可完成所有操作。“CEILING”旋钮用于设置压缩强度，并将电平直接恢复，因此您可以根据需要调整，最终回到初始状态。
* 关闭压缩器时，声音会呈现不同的色彩。“MODE OFF”旋钮会保留分立放大器和变压器，从而为不需要压缩的音轨提供类似调音台的厚重感。
* 电路设计在音频信号通过时进行优化。JFET 晶体管处于其真实曲线，分立运算放大器作为晶体管级，变压器采用独立的铁芯。

响应速度极快。 JFET负责增益控制，因此在瞬态结束前就能捕捉到声音，而其背后的分立运算放大器则在工作的同时，以各自的音色进行反作用。将其用于房间麦克风，距离感会转化为力度感；用于军鼓，它能精准捕捉鼓槌的敲击声。用于人声，它能保持音准，却丝毫没有刻意控制的感觉。

这种设计至今仍出现在已经安装了三个其他压缩器的机架中，原因就在于此。微妙之处并非其追求。鼓声听起来像是录音室级别的，而非现场录音，而且这种效果在房间的另一端就能听到，而不是在经过三次AB对比之后才出现。

组件详解：
* CEILING的阶跃增益来自原理图中的电阻梯形电路。每级提升2dB，该增益值直接测量自各个组件，而非拟合到曲线。
* DS侧链滤波器来自原理图中的开关网络，其中包含一个容易被忽略的部分：它能提升低频和高频。
* 输出变压器采用与原版相同的类型，并使用其铁芯进行建模。驱动它，它会达到饱和状态，而不是仅仅音量增大。
* 检测器会在采样之间重建峰值，频率约为 380 kHz，无论您的音频处理速率如何，因此即使在普通数字检测器读数较低的情况下，

它也能捕捉到短暂的瞬态信号。所有信息都会被记录下来，包括模型与实际测量硬件仍然存在差异的地方。

无压缩的色彩：
将 MODE 开关切换到 OFF 后，增益单元将不再起作用，但分立式输出放大器和变压器仍保持原位。此时，OUT 不再是补偿控制，而是驱动控制：按下它，然后拉回 TRIM 旋钮，即可将电平调整到所需位置。

在安静的音源下，这条路径保持干净。如果输入的是高电平音轨，并开启 OUT 开关，铁芯就会开始工作，三次谐波会明显领先于二次谐波，就像推挽式输出级饱和一样。这相当于在完全不需要压缩的音轨上使用了控制台级别的力度。大多数压缩器都要求你在两者之间做出选择，而这款压缩器则不然。它

的功能包括
：* 四种模式：C 模式为 2:1 压缩，不会干扰音轨；L 模式为 20:1 限幅，可瞬间消除声音；OFF 模式为不使用动态处理，仅使用放大器和变压器；BYP 模式为真正的旁路。
* CEILING 是压缩本身唯一需要的控制旋钮。只需轻轻扫一下，即可从几分贝的轻微压缩到全功率限幅。
* 前面板提供四种释放时间，从 0.1 秒的快速响应到 2.5 秒的流畅过渡。
* DS 模式可将检测器向高频端倾斜。在人声处理上，它无需单独的插件即可作为齿音消除器使用。
* 外部侧链、双声道/立体声/单声道模式、用于并行工作的干湿混合，以及变压器后微调功能，让您在驱动铁芯的同时仍能达到所需的电平。
* 表头下方的峰值保持读数，让您能够看到实际提升了多少。

它的独特之处在于：PCCN™
传统 DSP 对结果进行建模：固定的饱和曲线、脉冲响应，以及对一天行为的神经捕捉。而 PCCN 对原因进行建模：电路在音频流经时进行优化。您能听到曲线无法触及的声音。拐点出现在检波器中的整流器，增益单元达到极限时比率会变得陡峭，驱动输出会使变压器在放大器之前做出响应。

American FET| The 500-series FET compressor that put the snap in American records.

* The factory measured every single one before it shipped. Fixed readings, pass or fail. American FET is calibrated against that same list and hits all six level readings, in Compress and in Limit.
* Hear it before you pay for it. Further down: the same take with the plug-in in and out, level-matched so nothing wins by being louder. Switch between them and decide.
* One knob does the work. CEILING sets the squeeze and hands the level straight back, so you can lean on it and still land where you started.
* Colour with the compressor switched off. MODE OFF keeps the discrete amp and the transformer in the path, so you get console weight on tracks that need no compression.
* The circuit is solved while your audio runs through it. The JFET on its real curve, discrete op-amps as transistor stages, the transformer with its own iron.

It’s a fast one. A JFET does the gain riding, so the grab lands before the transient is over, and the discrete op-amps behind it push back with their own colour while it works. Put it on a room mic and distance turns into weight; on a snare it finds the stick. On a vocal it holds the line without ever sounding like it’s holding anything.

There’s a reason this design still turns up in racks that already have three other compressors in them. Subtlety isn’t the job here. Drums come back sounding like a record instead of a session, and you hear it from across the room, not after the third A-B.

Down to the parts
* The CEILING steps come off the resistor ladder in the schematic. 2 dB per step, measured off the parts rather than fitted to a curve.
* The D-S sidechain filter comes off the switch network in the schematic, including the part nobody notices: it lifts the deep bass as well as the top.
* The output transformer is the type the original was built with, modelled with its own iron. Drive it and it saturates instead of just getting louder.
* The detector reconstructs its peak between samples, at around 380 kHz whatever rate your session runs at, so short transients are caught where a plain digital detector reads low.

All of it is written down, including the places where the model still differs from the measured hardware.

Colour without compression
Switch MODE to OFF and the gain cell steps out of the way, but the discrete output amplifier and the transformer stay right where they are. Now OUT isn’t a make-up control any more, it’s a drive control: push it, and pull TRIM back afterwards to land the level where you want it.

On a quiet source that path stays clean. Feed it a hot track and lean on OUT and the iron starts working, third harmonic well ahead of the second, the way a push-pull output stage saturates. That’s console weight on a track that needs no compression at all. Most compressors make you choose between the two. This one doesn’t.

What you get
* Four modes: C for 2:1 compression that stays out of the way, L for 20:1 limiting that stops things dead, OFF for the amp and transformer without the dynamics, BYP for a true bypass.
* CEILING is the only control the compression itself needs. One sweep takes you from a gentle couple of dB to full-tilt limiting.
* Four release times off the front panel, from 0.1 s snap to 2.5 s glue.
* D-S tilts the detector towards the top end. On voices it becomes a de-esser without a separate plugin.
* External sidechain, dual / stereo-link / mono modes, dry-wet mix for parallel work, and a post-transformer TRIM so you can drive the iron and still hit your level.
* Peak-hold readout under the meter so you can see what it actually took off.

Why it’s different: PCCN™
Conventional DSP models the result: a saturation curve, an impulse response, a neural capture of one day’s behaviour. PCCN models the cause: the circuit is solved while the audio runs through it. You hear that where a curve cannot reach. The knee comes out of the rectifier in the detector, the ratio steepens as the gain cell runs out of room, and driving the output makes the transformer answer before the amplifier does.