Part 3 of the Vacuum Tube Audio Projects series features Preamp 5 and Preamp 6.
The Preamp 5 project is based on the book "Audio Amplifiers with Tube Preamp," pp. 45-46. It features a tone control circuit that uses a single potentiometer to vary the low and high frequency response of the amplifier. The circuit can change from a low-pass filter to a high-pass filter or vice versa by adjusting the potentiometer. When the potentiometer is in the center position, the circuit acts as an all-pass filter with no frequency attenuation.
The Preamp 6 project is based on an RCA design from the "RCA Receiving Tube Manual," RC-30, pp. 706-707. The circuit is a classic bass and treble tone control preamplifier that has been widely replicated and modified by many audio enthusiasts and hobbyists. In this project, we used a 12AX7, a 9-pin miniature twin triode tube, instead, as it is more common and easy to find. The 12AX7 also has a distinctive sound quality that appeals to many musicians and audiophiles. But, of course, other similar twin triodes can be used for this project as well.
For more details on how to make your own PCBs, go to: buildaudioamps....
29 окт 2024
