This product comes with quite a story. I remember many years ago, when I install audio system in my own car, I always look for a "black box" that I hope can me my system sounds great. I was hoping that this "black box" can change the whole sound of the system instantly. So I begin to try various IC preamp, like RockfordFosgate PA-1, Precision power PAR225, Zapco SX and PX, Nakamichi PA101, Audio control products, and almost all the signal processor available on the market. They are the best available. It turns out that my dream of such a "black box" is imposible.

For getting a good sounding system, first the basic system must have good sound basic. If you put solid state eq or preamp in a bad basic sound system, it will just make the whole system worse. Anything you adjust will be wrong. You can only put these solid state processor in a good system, to make it better. 

This is why I turn into this tube preamp. This preamp acts a little different than solid state one. Because of the small current, and high voltage involved, this preamp is very sensitive, compared to the solid state one. Solid state works in higher current than the tube preamp. Many tone signal are burried with this high current involved. This tube preamp can "see" more tone than the solid state one. The result, well you can hear all the sound that misses with solid state processor. But this is not all. The most important result of this tube preamp is the total "tonal balance". This tonal balance of the whole audio spectrum makes it produces nice audio system. It is quite difficult to explain a good tonal balance. It is more detailed, crystal clear, but not harsh (like you boost your treble or eq), it is more deep, but not like you push the loudness button on, etc. You will have to experience it yourself. 

This is the tube preamplifier for car audio. It utilizes high voltage up to 140VDC for the supply.