Guitar Tone Control

Stand-alone, 9V battery powered unit

Three-level input selector, three-band tone control

Device purpose:

This preamplifier was designed as a stand-alone portable unit, useful to control the signals generated by guitar pick-ups, particularly the contact "bug" types applied to acoustic instruments. Obviously it can be used with any type of instrument and pick-up.
It features a -10dB, 0dB and +10dB pre-set input selector to adjust input sensitivity, in order to cope with almost any pick-up type and model.
A very long battery life is ensured by the incredibly low current consumption of this circuit, i.e. less than 800µA.

Parts:

P1,P2_________100K   Linear Potentiometers
P3____________470K   Linear Potentiometer
P4_____________10K   Log. Potentiometer

R1____________150K   1/4W Resistor
R2____________220K   1/4W Resistor
R3_____________56K   1/4W Resistor
R4____________470K   1/4W Resistor
R5,R6,R7_______12K   1/4W Resistors
R8,R9___________3K9  1/4W Resistors
R10,R11_________1K8  1/4W Resistors
R12,R13________22K   1/4W Resistors

C1____________220nF   63V Polyester Capacitor
C2,C8___________4µ7   63V Electrolytic Capacitors
C3_____________47nF   63V Polyester Capacitor
C4,C6___________4n7   63V Polyester Capacitors
C5_____________22nF   63V Polyester Capacitor
C7,C9_________100µF   25V Electrolytic Capacitors

IC1___________TL062   Low current BIFET Dual Op-Amp

J1,J2__________6.3mm. Mono Jack sockets

SW1______________1 pole 3 ways rotary or slider switch
SW2______________SPST Switch

B1_______________9V PP3 Battery

Clip for PP3 Battery

Circuit operation:
IC1A op-amp is wired as an inverting amplifier, having its gain set by a three ways switch inserting different value resistors in parallel to R4. This input stage is followed by an active three-band tone control stage having unity gain when controls are set in their center position and built around IC1B.

Technical data:

Frequency response:20Hz to 20KHz -0.5dB, controls flat.
Tone control frequency range: ±15dB @ 30Hz; ±19dB @ 1KHz; ±16dB @ 10KHz.
Maximum input voltage (controls flat): 900mV RMS @ +10dB input gain; 7.5V RMS @ -10dB input gain.
Maximum undistorted output voltage: 2.5V RMS.
Total Harmonic Distortion measured @ 2V RMS output: <0.012% @ 1KHz; <0.03% @ 10KHz.
THD @ 1V RMS output: <0.01%
Total current drawing: <800µA.

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60 Watt Guitar Amplifier + Tone Control

The following is a circuit of amplifiers are equipped with the appropriate regulatory tone in use to strengthen the electric guitar, using a single-rail supply of about 60V and capacitor-coupling for the speaker . The advantages for a guitar amplifier are the very simple circuitry, even for comparatively high power outputs, and a certain built-in degree of loudspeaker protection, due to capacitor C8, preventing the voltage supply to be conveyed into loudspeakers in case of output transistors' failure.

  Skema Rangkaian Guitar Amplifier + Tone Control

In all cases where Darlington transistors are used as the output devices it is essential that the sensing transistor (Q2) should be in as close thermal contact with the output transistors as possible. Therefore a TO126-case transistor type was chosen for easy bolting on the heatsink, very close to the output pair

R30 must be trimmed in order to measure about half the voltage supply across the positive lead of C7 and ground. A better setting can be done using an oscilloscope, in order to obtain a symmetrical clipping of the output wave form at maximum output power

Note:
To set quiescent current, tide ampare meter in series between supplay with this series, then do the following

• Set the volume control to the minimum and Trimmer R3 to its minimum resistance.
• Power-on the circuit and adjust R3 to read a current drawing of about 30 to 35mA.
• Wait about 15 minutes, watch if the current is varying and readjust if necessary.

List component

R1,R2______________68K 1/4W Resistors
R3________________680K 1/4W Resistor
R4________________220K 1/4W Resistor
R5_________________33K 1/4W Resistor
R6,R16______________2K2 1/4W Resistors
R7__________________5K6 1/4W Resistor
R8,R21____________330R 1/4W Resistors
R9_________________47K 1/4W Resistor
R10_______________470R 1/4W Resistor
R11_________________4K7 1/4W Resistor
R12,R20____________10K 1/4W Resistors
R13_______________100R 1/4W Resistor
R14,R15____________47R 1/4W Resistors
R17,R18,R19_______100K 1/4W Resistors
R22__________________6K8 1W Resistor
R23,R25_____________470R 1/4W Resistors
R24__________________2K 1/2W Trimmer Cermet
R26,R27_______________4K7 1/2W Resistors
R28________________220R 1/2W Resistor
R29__________________2K2 1/2W Resistor
R30_________________50K 1/2W Trimmer Cermet
R31________________68K 1/4W Resistor
R32,R33______________R47 4W Wirewound Resistors


C1,C4,C5,C6________10µF 63V Electrolytic Capacitors
C2_________________47µF 63V Electrolytic Capacitor
C3_________________47pF 63V Ceramic Capacitor
C7_________________15nF 63V Polyester Capacitor
C8_________________22nF 63V Polyester Capacitor
C9________________470nF 63V Polyester Capacitor
C10,C11,C12________10µF 63V Electrolytic Capacitors
C13_______________220µF 63V Electrolytic Capacitor
C14,C15,C17,C18________47µF 63V Electrolytic Capacitors
C16________________100µF 25V Electrolytic Capacitor
C19_________________33pF 63V Ceramic Capacitor
C20_______________1000µF 50V Electrolytic Capacitor

P1,P2______________10K   Potentiometers
P3_________________10K   Potentiometer

D1,D2____________BAT46   100V 150mA Schottky-barrier Diodes
D3_________________LED

Q1,Q3____________BC546    NPN Transistors
Q2_______________BC556    PNP Transistor
Q4,Q5____________BD139    80V 1.5A NPN Transistors
Q6_____________MJ11016   120V 30A NPN Darlington Transistor
Q7_____________MJ11015   120V 30A PNP Darlington Transistor

J1,J2___________6.3mm. Mono Jack sockets
SW1,SW2___________SPST Switches
SPKR______________speakers  8 or 4 Ohm with Minimum power 75W

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Quality Video Mixer GX4201

The modules described in this application note can be used as stand-alone multiplexers for both NTSC/PAL broadcast and any HDTV format applications. In addition, by virtue of their size, their performance and the SIP pin outs, they may be used to form larger n x m, professional video matrices. Each GX4201 device is a 1x1 video crosspoint characterised by a low distortion, unilateral signal path consisting of emitter followers at the input and output with level shifting circuits in between.

High definition TV places additional requirements on crosspoint performance in video switching systems.  These include a wider flat frequency response and better high frequency off isolation  and  crosstalk  performance.   In  larger  routing expandability  and  repeatability  of  system  parameters fromchannel to channel, become even more important. The modular multiplexers described in this application note  take these, as well as other points, into consideration and  provide an optimal solution for the video design engineer.  The multiplexers are realised using Gennum's GX4201 wideband  1x1 crosspoint IC.

Video Mixer GX4201 Schematic

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Digital Message Recorder

The purpose of this digital electronics project is to record messages using a dedicated voice recorder integrated circuit. Recordings are stored in a non volatile memory cells, which means that the message will still be saved even though power has been removed from the device.

Winbond’s ISD2500 Series provide high-quality, single-chip, Record/Playback solutions for 60 seconds to 120 seconds message applications. The CMOS devices include an on-chip oscillator, microphone preamplifier, automatic gain control, antialiasing filter, smoothing filter, speaker amplifier, and high density multi-level storage array. In addition, the ISD2500 is microcontroller compatible, allowing complex messaging and addressing to be achieved. Recordings are stored into on-chip nonvolatile memory cells.

Circuit Description

The ISD25120 has several modes of operation. The mode used here is as a multi-message recorder. You may record as many messages as you want up to 120 seconds of memory space.

Put the SPDT switch into the Record position and just push & release the Start/Pause button to start recording. The Record LED goes on. Push the Start/Pause button to Pause - stop recording. That is the end of Message 1. Sometime later you can record a follow on message, Message 2, by pushing the Start/Pause button again. When you put the switch to Play the messages will playback. Only one message will be played back at a time. You must push Start/Pause again to get the next message. The Reset switch will move the internal address pointer back to the start of the memory space.

Parts List

The complete specifications of the Winbond ISD25120 IC can be obtained from ISD25120 Digital Electronics Project Specifications. 

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