Tube Bass Preamp V. 1.3

http://www.sugardas.lt/~igoramps/article30.htm

Preamplifier version 1.3 is designed for easy reloading and adjustment of bass tone. Entrance of mu-stage (general characteristic of all my tube amps) provides a great preamp and minimum distortion. The second stage is collected by the classical scheme, gives the effect of overload. To mitigate the effect of filters have been added at the input and output stage. For more hard overdrive can be proportional (to save tone) to increase the capacitors C12 and C13. 
two-band tone control is a customized version of the filter Baksandala. It allows you to add bass, as well as add and cut high. The last stage provides a high level output signal.