5751 is the designation for a low-voltage, low-noise avionics vacuum tube popular as a pre-amplification tube in guitar amplifiers. The 5751 is a modified version of the 12AX7 and, having a gain factor of 70-80 (as opposed to the 12AX7's 100), is used to "soften up a harsh modern amp". [1]
References
- ^ Pittman, Aspen (2003). The Tube Amp Book. Hal Leonard. p. 132. ISBN 978-0-87930-767-7.