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Super pre tone control project using LF353

I always recommend relatively many circuits or project on the pre tone control. Today we see other interesting project. (Please do not get bored them).

We can divide normally type of the tone control are 2 types as following.

1. Passsive Tone Control
2. Active Tone Control

A stype of the passive tone control circuit be shown in figure 1. We do not widely used this circuit. Because sound quality is reduced and low performance.

typical-passive-tone-control


Figure 1 Typical passive tone control

We like to use. the active tone control type that most familiar. is the Baxandall type circuit As shown in Figure 2.

typical-negative-feedback-tone-baxandall-type
Figure 2 typical negative feedback tone (baxandall type)

Advantage of this active tone control type is not cause loss signal. We may understand the function of this circuit easier. By considering the comparison of circuit in Figure 3.

simple-feedback-CKT
Figure 3 simple feedback CKT

See that the gain of the circuit is equal to the Rb / Ra. So if Rb = 10Ra we have gain = 10.

IF Ra=Rb will be gain = 1

If we return to consider in figure 2, will seen that C1, R1 & C2 + R2 is connected together that the velue its Impedance will decrease as the frequency increases.

If we adjust RV1 Ra1 value is greater than C1 + R1. then The gain of the line M in figure 4.

behavior-of-negative-feedback-tone-control-overlap-effect-exaggerated
Figure 4 Behavior of negative feedback tone control (overlap effect exaggerated)

On the contrary, if we adjust the volume in the other direction. Will have gain of circuit as line N. In figure 4 RV1 serves as the Treble control.

Then consider the P3 + C3 and C4 + R4 will see that resistance is even higher. When lower frequency so have the gain of circuit as figure 4 then P, Q to R5-resistor that serves as a separate circuit, the two part, not to interfere with each other.

Which in practice. Can not be strictly separated circuits. That is when we adjust the bass – treble would be with prejudice.

how modify so May be split both control circuit independent decisively as show in figure 5

sequential-two-stage-tone-control-which-avoids-inter-action-between-controls
Figure 5 Sequential two-stage tone control which avoids inter-action between controls.

From these principles, we can design the tone control circuit solutions.As circuit shown in Figure 6.

super-tone-control-circuits
Figure 6 Super tone control circuit.

We use the circuit of TR1, TR2 transistor acts as a Matching circuit. Between input and this super tone control. By Q1 is connected as emitter follower type. and have Q2 is a constant cureent cource circuit.

The IC1-LF353 will act as the adjust treble sound. And IC2-NE5532N serves as a fine bass voice. Because the normal tone control and pre amplifier will work best well. When they is driven by a circuit with low impedance, and the load applied to a high resistance.

How to build
Order to PCB layout and positioning devices in Figure 7 . I can not tell how many, because I believe you can do it.
pcb-of-Super-tone-control
Figure 7 PCB of Super tone control

Part list
IC1___________LF353 Wide Bandwidth Dual JFET Input Operational Amplifier or NE5532N or M5218
*** but M5218 is very old ICs.
Q1, Q2________BC549 45V 100mA NPN Transistor
1/4W +/- 1% Resistors
R1, R5, R15___________2.2K
R2, R16______________100 ohm
R3___________________ 270K
R4, R8, R9, R11, R12____10K
R6______________________2.2K
R7, R10, R13, R14______100K
R15____________________3.3K
VR1, VR2______________100KB Linear Potentiometer
VR3____________________50KACT non Linear Potentiometer

Electrolytic Capacitors
C1, C2, C7______________10uF 16V
C12, C13________________100uF 25V
Polyester Capacitor
C3, C4__________________0.0047uF 50V
C5, C6__________________0.047uF 50V
C8______________________0.001uF 50V
C9______________________0.01uF 50V
C10, C11________________0.1uF 50V

This Post Has 9 Comments

  1. hi
    why parts with list on parts the top pcb are different?
    for example : Part list
    IC1___________LF353 Wide Bandwidth Dual JFET Input Operational Amplifier or NE5532N

    on pcb : m5218

    please help me thanks

  2. Hi,
    Thanks for your feedback.
    Yes, you can all ICs number M5218 is very old ICs.

  3. Hi I’ve just seen this cct and can’t wait to give it a go; I’m a lifetime audio aficionado and it’s always rewarding to find a rare circuit to try and of course to hear it, how is its sound, how different is from others about sound characteristics; when I find time to try I’ll make it and will let you know. Tnx for sharing your ccts.

  4. Rua dos prazeres
    taquara

  5. O, IC1-LF353 is best for managing acute.
    And the NE5532 is best for the serious donate control?
    Or whatever, which is the best.
    Grateful.

  6. Help me in the part lists plz.

  7. Can I get the whole kit or else the pcb from market? If so from Where? Please help.

  8. THANK YOU. MY NAME OP. MEHMET TA2DC 73’S.

    1. Hi MEHMET,
      It’s my pleasure.

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