嗨克里斯，我正在寻找购买一个新的放大器，销售Spiel说这是'A级'。这是什么意思？
– Scott, Barnsley
克里斯芬纳:你好,斯科特,大问题!肯定有很多of confusion around amplifier classes and what they mean to the end user.
The output stage of an amplifier can operate in many different ways, using various different methods. We use the Class system to give a broad indication of an amplifier’s characteristics and performance. These classes, of which there are nine in total, are related to the time period that the amplifier is passing current. This is expressed as fraction of the signal waveform applied to the input. Some of the classes contain sub-classes, usually indicated by a suffix.
The nine main classes are: A, AB, B, C, D, E, F, G, and H. Valve-amp-loving guitar players really only need concern ourselves with just three of these classes: A, AB, and B.
Class A
本课程中的输出阀正在进行100％。由于正弦波可以被认为是贯穿螺旋弹簧的侧视图 - 看看吉他上的振动吉他弦，看看我的意思 - 我们说导电角度为360度。
由于这些阀门工作100％的时间，他们不会休息，因此它们实际上是非常效率的。它们的最大理论效率仅为25％，这就是为什么A类放大器不会产生非常强大的权力。这种设计的上行程序是，电路可以相对简单地建立和维护，同时产生更好的中高频率性能。
如果我们以一对EL34为例，在A类中，您将能够生产大约20瓦的RMS功率。
Class B
You probably won’t come across a Class B guitar amplifier but we need to understand what they are anyway. In this class, each output valve only conducts exactly one half of the input signal, so the conduction angle is 180 degrees. One valve will conduct the positive half, and the other conducts the negative.
As we now have a 180 degrees rest period for each valve in-between conduction events, we can use that to cool the valve down and therefore push it harder when it is conducting. A Class B amplifier can be much more efficient that a Class A, with a maximum efficiency of over 75 per cent. You can make big power when operating in Class B, but like every other class it has drawbacks. For guitar use, a Class B amplifier won’t sound very musical with an odd balance of both even and odd-order harmonics when overdriven.
在B级，我们的一对EL34s将能够相对容易地生产近80瓦。
AB.
So what is Class AB? It’s as the name suggests – a mix of both. In Class AB, the conduction angle is greater than 180 degress but less than 360 degrees. It it up to the circuit designer to choose where that point is. Usually in a guitar amplifier, the signal will stay in the Class A region where it is amplified with good fidelity and will move closer to Class AB when pushed harder. A classic example of this is thevox.AC30，它是A级的清洁，但是当稍微推动时快速进入AB。
Nearly every guitar amplifier with multiple output valves will operate in Class AB. Class AB is more efficient that Class A, but less so than Class B. Our EL34s have a slightly easier time in Class AB than B, with typical outputs ranging from 35-50 watts.
那么，放大器的类是否会影响音调？因为这就是我们都想知道的，对吧？好吧，是的，没有。
Whilst there are tonal differences between the classes, they are easiest to spot in a hifi application, whereas in our low-fidelity guitar amplifiers, it’s less so. You see, even the cleanest guitar signal is easily way more distorted than you’d ever find in a hifi. For reference, a hifi is considered to be ‘clean’ up to around 0.5 per cent distortion, although modern units will never stray above 0.1 per cent. Our guitar amplifiers on the other hand rarely drop below 1 per cent and some manufacturers will consider 10 per cent as clean operation. If you want to know what your clean guitar signal really sounds like, plug into a modern bass amplifier – you’ll immediately notice the missing harmonics and overtones generated by your guitar amp.
吉他放大器中还有其他功能，影响音调远远超过它的课程，例如TONESTACK或偏置输出阀的方法，所以就玩家而言，它可能被认为是微不足道的。从设计人员的角度来看，它是您的整个电路构建的基础。
使用课堂系统到市场并销售放大器？嗯，这只是......营销。
访问riftamps.com.更多关于裂谷的英国建造精品安培的范围。