haoDIY创好电子音响电脑科技DIY小制作发明移动版

Figure 2 shows one channel of a suggested wiring for the preamp. 图2显示了一个频道的一个建议的布线前置放大器。This is duplicated exactly for the other channel, and the switch and volume control are common to both. 这是完全的复制其他渠道,开关和音量控制是共同的。The CD input bypasses all electronics and is applied directly to the volume control, and the low level inputs use the gain of the modules to bring their level up to that of the CD player. CD输入绕开所有电子和是直���用于音量控制,和低水平输入使用获得的模块将他们的水平的CD播放器。This introduces a bit more switching, but many audiophiles will prefer this method. 这引入了更多的开关,但是很多发烧友会更喜欢这种方法。Note that when switched to CD, the input of the preamp is earthed to prevent any noise pick-up.注意,当切换到CD,输入的前置放大器是接地的,以防止任何噪音拾音器。

The switching requires a 4-pole, 5 position rotary switch for both channels, and a dual-gang pot. I strongly suggest that a linear pot is used, with the resistor as shown. 开关需要一种,5的位置旋转开关两通道和一个双帮派锅。我强烈建议使用一个线性锅,电阻器如图所示。Although this produces a variable impedance to the source, it is a better approximation of a log pot than those you can buy at normal outlets, and has much better tracking between channels. 尽管这会产生一个可变阻抗源,这是一个更好的近似的日志锅比你可以买到在正常的商店,有更好的跟踪频道之间。If you can get a conductive plastic logarithmic pot, do not use the resistor, as these are generally much better than the normal carbon film types, and the resistor will ruin the log curve.如果你能得到一个导电塑料对数锅,不要使用电阻器,因为这些通常要比正常的碳膜类型,和电阻器将毁掉日志曲线。

In some cases - due to an amplifier with unusually low input sensitivity for instance - an output gain stage might be needed. 在某些情况下,由于一个放大器有着异乎寻常的低输入灵敏度例如——一个输出增益阶段可能需要。This would typically use another gain module using the circuit above, but generally with lower gain. 这通常使用另一个增益模块使用电路以上,但通常较低的增益。It is expected that a gain of 2 (6dB) will be enough for any amplifier, since this will provide an output of 4V RMS for a CD players typical 2V output. 预计上涨2(6分贝)将足以让任何放大器,因为这将提供一个输出4 v RMS对于一个CD播放机典型的2 v输出。I have found that with typical sources, a preamp gain of about 10dB is sufficient to drive a typical power amplifier, so the additional gain will probably not be needed.我发现,与典型的来源,一个前置放大器增益的大约10分贝是足以驱动一个典型的功率放大器,因此额外获得可能不需要。

The photo shows what the new board looks like when fully populated according to the construction details.这张照片显示了新董事会看起来像当完全填充根据施工细节。

The power supply must be free from hum and noise, and the circuit shown in Project 05 (Rev-B) is highly recommended. 电力供应必须摆脱哼和噪音,和电路显示在项目05(启b)高度推荐。A discrete circuit could also be used, but P05 is a far better proposition. 一个离散的电路也可以使用,但是P05是一个更好的命题。The variable regulator ICs have extremely low noise. 变量调节器ICs有极低噪声。A single P05 will easily power about ten P37-A boards ... 一个P05将容易功率大约十P37-A董事会……more than anyone is likely to need.比任何人都可能需要。