Schematic Volt: Bass

Monday, October 20, 2014

Bass Booster Circuit

Increase the bass output of your present instrument at modest cost!

Bass Boost is todays sound... whether its the driving, gut-vibration pulsation of disco, or the solid bass line of soft, hard, or laid-back rock. One way to get the modern bass-boost sound without running out and buying an all-new expensive piece of equipment is to use a Bass Booster between your guitar, electronic organ or what-have-you, and the instrument amplifier.

A bass booster strips the highs from the instruments output signal and amplifies low frequencies, feeding on "all-bass" sound to the instrument amplifier. Naturally, the bigger the speaker used with the amp, the more powerful the bass: use 15-inchers with the Bass Booster and you can rattle the windows. Bass Booster is powered by an ordinary 9 volt transistor radio battery. It can be assembled on a small printed board or on a veroboard using point to point wiring. The booster connects between your instrument and its amplifier through two standard RCA Jacks.

Circuit Diagram:

Bass Booster Circuit Diagram

Parts:
P1 = 50K
P2 = 100K
R1 = 22K
R2 = 470K
R3 = 47K
R4 = 10K
R5 = 470R
R6 = 1K
Q1 = 2N2222
C1 = 2.2uF-25v
C2 = 100nF-63v
C31 = 00nF-63V
C4 = 3.3uF-25v
C5 = 470uF-25v
D1 = 5mm. Red Led
Q1 = 2N2222
B1 = 9v Battery
J1 = RCA Audio Input Socket
J2 = RCA Audio Output Socket
S1 = On-Off Switch

Using Bass Booster:

Connect your electronic guitar or other electronic instrument to input jack J1; Connect output jack J2 to your instruments amplifiers normally-used input. With power switch S1 off, key S2 so the instrument feeds directly to the instrument amplifier. With P2 set full counter-clockwise (Off), turn power switch S1 on, key S2 once, and advance P2 for the desired Bass Boost level. To cut back to natural sound just stomp down on S2 and key the Bass Booster out. Dont worry about leaving power switch S1 on for several hours of a gig. The circuit pulls less than 1mA from the battery, so battery will last many, many months.

source :http://www.ecircuitslab.com

Modular Preamplifier Tone Control Bass and Treble Controls

Circuit diagram

Parts:

P1,P2___________10K Linear Potentiometers
 (twin concentric-spindle dual gang for stereo)

R1_____________100K 1/4W Resistor
R2,R6___________18K 1/4W Resistors
R3_______________3K3 1/4W Resistor (18K for shelving curves: see Notes)
R4,R5____________1K8 1/4W Resistors (10K for shelving curves: see Notes)
R7_____________560R 1/4W Resistor

C1_______________1µF 63V Polyester Capacitor
C2_______________4n7 63V Polyester Capacitor (3n3 for shelving curves: see Notes)
C3_______________1µ5 63V Polyester Capacitor (100nF for shelving curves: see Notes)
C4,C7__________100nF 63V Polyester Capacitors
C5,C8___________22µF 25V Electrolytic Capacitors
C6,C9_________2200µF 25V Electrolytic Capacitors

IC1___________TL072 Dual BIFET Op-Amp
IC2___________78L15 15V 100mA Positive Regulator IC
IC3___________79L15 15V 100mA Negative Regulator IC

D1,D2________1N4002 200V 1A Diodes

SW1____________DPST Toggle Switch

J1,J2__________RCA audio input sockets
J3_____________Mini DC Power Socket

Comments:

Needing a Tone Control, this module can be inserted in the chain between the Control Center and the Power Amplifier.
The circuit is based on an original design of Reg Williamson, published on Electronics World + Wireless World, Circuit Ideas, January 1991.

This tone control circuit will take the form of either the traditional bass and treble adjustment or the shelving type, which is similar to a "tilt" control but with independent bass and treble.
Asymptotic slopes for both are about 4dB/octave, but begin to flatten out at 100Hz and 10kHz, reaching a maximum of ±15dB at the ends of the audio band.
Component values in parenthesis are those for the shelving type of control. In this case, the shelf begins at about 250Hz and 4kHz, flattening to a ±6dB maximum an octave above or below; the central point is 1kHz.
Reactive elements for the low end include a generalized impedance converter, which simulates an inductor in series with a resistor (gyrator).

When set to the electrical centers of their respective controls, the reactive elements of the equalizers are virtually out of circuit. With these settings, the circuit behaves as a unity gain amplifier with 100% negative feedback. Even so, reactive elements can be switched out altogether with a DPST on/off switch.

As with the other modules of this series, each electronic board can be fitted into a standard enclosure: Hammond extruded aluminum cases are well suited to host the boards of this preamp. In particular, the cases sized 16 x 10.3 x 5.3 cm or 22 x 10.3 x 5.3 cm have a very good look when stacked. See below an example of the possible arrangement of the front and rear panels of this module.

Notes:

To build the shelving type of control, use the values shown in parenthesis for R3, R4, R5, C2 and C3
The circuit diagram shows the Left channel only and the power supply.
Some parts are in common to both channels and must not be doubled. These parts are: P1 and P2 (if twin concentric-spindle dual gang potentiometers are used), IC2, IC3, C4, C5, C6, C7, C8, C9, D1, D2 and J3.
This module requires an external 15 - 18V ac (50mA minimum) Power Supply Adaptor.

Technical data:

Input sensitivity:: 1V RMS for 1V RMS output
Maximum output voltage:: 9.5V RMS into 10K load
Frequency response:: flat from 20Hz to 23KHz
Total harmonic distortion @ 1.5V RMS output:: 100Hz = 0.004% 1KHz = 0.004% 10KHz = 0.002%
Total harmonic distortion @ 6V RMS output:: 100Hz = 0.003% 1KHz = 0.003% 10KHz = 0.03%; More Detail you can see at http://redcircuits.com/Page152.htm