12ax7 Tube Pre-amplifier with Treble Bess Control

The circuit refers to the British PJ. Baxandall type tube tone control circuit

It is a low-distortion tone control circuit that uses frequency negative feedback. Although it is a negative feedback type tone control circuit, not all tone control functions are completed by the feedback loop. It changes the frequency characteristics of the coupling section between the first stage tubes and combines it with the changes provided by the negative feedback to boost or attenuate the low-frequency and high-frequency signals. The characteristic of this circuit is that it has a wide control range and And the two potentiometers are placed in the middle position, so that it can achieve a flat response curve.

During control, the shape of the high-frequency response curve remains almost unchanged but shifts along the frequency axis. Although the low-frequency response curve is not constant, its variation is smaller than that of most continuous adjustable circuits.

The Baxandall type tone control circuit is the best-sounding tone circuit and is widely used in professional stage audio equipment around the world.

Compared to tone circuits with discrete components and operational amplifier tone controls, electronic tube devices have the following advantages due to their unique working methods: high input impedance, large dynamic range, low thermal noise, good transient response, low distortion, and simple circuit design.

The circuit adopts 6z5p high-voltage rectification, 6p1 electron tubes for high-voltage stabilization output, and two 12ax7b tubes for amplification.

Parameters

Tubes:  6z5p*1  6p1*1  12ax7b*2

The Overall gain is 10db

frequency response: 15-35 KHZ

Signal-to-noise ratio (SNR): 80db

Harmonic distortion :<3%(1KHz)

input sensitivity is 1V

input impedance: 100K

output impedence: 600 ohm

supply voltage:  AC 110v 230v Optional

4 groups of signal inputs, 1 group of output

 About the use

 Note: If you connect to a power amplifier, the pre amp can only be used with pure power amplifier, Not compatible with most AV amplifier with tone or preamp.

Feel Free to contact us if there are any questions.