Sunday, January 24, 2016

What is a preamplifier?

What is a preamplifier? 

What is a preamplifier? It could be difficult to tell, the official explanation was below.

A preamplifier is the role of audio amplification, generally because audio signals are very small and cannot drive power amplifier directly, you must install a front voltage amplification circuit to amplify signal then drive power amplifier. Also, due to the diversity of input signals, such as input signal voltage level, as well as high and low input impedance, a preamplifier will fit to the strength of the input signal to set up a different magnification time. And if internal resistance doesn’t match between signal sourcing and amplifier, it makes to lose a dynamic frequency response, details! Besides adjusting the volume, active preamplifier also can be used for preliminary amplifier, reduce internal resistance difference between the signal sourcing and power stage, which is used as a buffer.

Finally, because varieties of users have various audio sources, output signal amplitude and impedance that less people actually study, there is a big difference at listening actual sounds, on the one hand it is audio output signal amplitude is different, on the other hand is internal resistance  mentioned above. This has created more songs we heard was substantially compress it’s dynamic, and detail is lost, frequency response is attenuated. Very apparently we were using computer or cell phone to connect power amplifier when listening to some music, it doesn't even feel to the low frequency and high frequency is not so bright small volume situation. No matter how good computer sound card and how good the sound system, it could not find the original tapes of the time!

Here, 6N2 tubes we used the most common one, we specifically tune the circuit for computer sound source without expensive components piled up, but a reasonable configuration, we choose the most suitable work point, and precisely matched the key components to ensure circuit work at the best.

Circuit Diagram

More details, please find here!