Free Circuit Diagram

For the best advantage as a low noise high input impedance device, the preamp and tone control uses JFET. If the circuit reaches harmonic distortion levels of less than 0.05% with a S/N ratio of over 85 dB, all device parameters are non-critical. 18 dB of cut and boost is allowed by the tone controls. [...]

This is a HI-FI tone control circuit with high Z input. This circuit is used to control HI-FI tone. Here is the circuit:

To buffer op-amp operated feedback type tone control circuit, this circuit uses 2N3684 JFET. The 2N3684 JFET is implemented on this circuit because it has low noise characteristics and provides the function of [...]

The LM4610 uses DC  signal to control the tone (bass/treble), volume, and balance circuit.   The advantages of using DC control is that you can use a mono potentiometer to control both channel, even you can use a DC signal generated from a DAC, so you can control the sound using microcontroller or microprocessor. This circuit [...]

Using a special purpose single IC chip LA3600, we can build a graphic equalizer with low components count.  The internal design of the chip uses transistors gyrator circuit, with connections to external capacitors to set the response. This graphic equalizer circuit is suitable for tape-recorders, radio-cassette recorders, car stereos, or home theater sound systems. You [...]

Unlike the 10-band graphic equalizer in our previous circuit that use a gyrator circuit, this 3-band graphic equalizer circuit uses Baxandall topology, similar with the Baxandall tone control but with additional mid frequency control. The figure below shows the schematic diagram of the circuit.

The operational amplifier employ an LF351 IC chip, but any low noise [...]

This circuit is similar to our previous tone control circuit, a bass-treble tone control circuit, but here we present the formula for design your tone control’s custom frequency response. Here is the schematic diagram and formula of the tone control circuit:

Almost all op-amp type can be used, as long as they have high input impedance, [...]