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Amplifiers: Audio Circuits
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Audio Amplifiers:   #'s       A - D        E - M        N - R      S - U     
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Last Updated: December 07, 2017 02:03 PM

Circuits Designed by Dave Johnson, P.E. :
TV /VCR Remote Range Extender Circuit  -  I often get frustrated by how poor some infrared remotes in many new electronic devices operate.  I used to be able to turn on the TV from 30 feet away.  Now, it seems that I have to get within 15 feet.  To address this issue, I designed the circuit shown below.  The circuit taps into the TV remote’s existing infrared LED and drives 8 more efficient devices.  The result is a communications range some 4 to 5 times longer.   . . . Circuit by Dave Johnson P.E.-October 05, 2005

Video Signal Edge Enhancements  -  I designed this circuit many years ago, based on the claims that the technique would improve the quality of standard TV images.  The circuit adds information to the edges of the objects and was reported to bring out more detail.  After building and testing . . . Circuit by David A. Johnson P.E.-July 08, 2000

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

TDA based Amplifier Schematics -  Schematics for many TDA based amplifiers.  

TDA1010 9W Power Amplifier -  The TDA1010 is a monolithic integrated class-B audio amplifier circuit in a 9-lead single in-line (SIL) plastic package.  The device is primarily developed as a 6 W car radio amplifier for use with 4 Wand 2 Wload impedances.  The wide supply voltage

TDA1011 6.5W Power Amplifier -  The TDA1010 is a monolithic integrated class-B audio amplifier circuit in a 9-lead single in-line (SIL) plastic package.  The device is primarily developed as a 6 W car radio amplifier for use with 4 Wand 2 Wload impedances.  The wide supply voltage

TDA1013 4.2W Power Amplifier -  The TDA1013 is an integrated audio amplifier circuit with DC volume control, encapsulated in a 9-lead single in-line (SIL) plastic package.  The wide supply voltage range makes this circuit ideal for applications in mains and battery-fed apparatus such as television receivers and record players.  The DC volume control stage has a logarithmic control characteristic with a range of more than 80 dB; control is by means of a DC voltage variable between 2 and 6.5 V.  

TDA2002 8W Car Radio Power Amplifier -  TDA2002 8W Car Radio Power Amplifier with 10V-14V single rail voltage supply.  Power output is 8W.  Recommended for speakers with 2-8 ohm impedance

TDA2003 Audio Amplifiers -  TDA2003 is a cheap amplifier that is designed to run on single rail power supplies (unipolar).  It provides a high output current capability (up to 3.5A), very low harmonic and cross-over distortion.  TDA2003 10W car radio audio amplifier TDA2003 18W bridged audio amplifier TDA2003 can be used as an BCL (bridged amplifier) and __ Designed by Popescu Marian

TDA2005 Audio Amplifiers -  TDA2005 is a class B dual audio power amplifier specifically designed for car radio applications.  Its high current capability (up to 3.5 A) and the ability to drive very low impedance loads (down to 1.6 ohms) makes this circuit a good choice for cheap power booster amplifiers.  TDA2005 stereo amplifier 2 x 10W TDA2005 20W __ Designed by Popescu Marian

TDA2006 12W Power Amplifier -  12W TDA2006 power audio amplifier with 11V to 14V single voltage supply.  For speakers with 2-8 ohm impedance

TDA2030 + transistors BD908/BD907-18W HI-FI Audio Amplifier & 35W driver -  TDA2030 + power transistors (TIP41, TIP42 or 2SC1061, 2SA761 or BD908, BD907 or BD911, BD912 or TIP31, TIP32) for an audio amplifier up to 40 Watts.  Simple installation, no special settings requires and uses few components.  The amplifier is based on the TDA2030 IC and two transistors that can be (TIP41, TIP42 or 2SC1061, 2SA761 […] __ Designed by Antonio Rodrigues

TDA2030 8 Watt Amplifier -  Although the TDA2030 can deliver 20 watts of output power, I deliberately reduced the output power to about 8 watts to supply 10 watt speakers.    Input sensitivity is 200mV.  Higher input levels naturally will give greater output, __ Designed by Andy Collison

TDA2030 Audio Amplifiers -  TDA2030 is a monolithic integrated circuit in Pentawatt package, intended for use as a low frequency class AB amplifier.  It provides 14W output power (d = 0.5%) at 14V/4Ω at ± 14V or 28V, the guaranteed output power is 12W on a 4Ω load or 8W on a 8Ω TDA2030 10W audio amplifier circuit TDA 2030 audio amplifier __ Designed by Popescu Marian

TDA2030-14W Single Chip Power Amplifier -  There are many instances where a very simple to build (and relatively cheap) power amplifier is needed.  The TDA2030 is a single chip amplifier capable of 14W output into 4 ohms with a few external components.  It can be used for almost any application you could think of.  

TDA7294 Amplifier -  The TDA7294 amplifier module is a monolithic integrated circuit.  It is intended for use as an audio class AB amplifier in hi-fi applications.  It has a wide voltage range and output current capability, enabling it to supply the highest power into both 4 ohm and 8n ohm loads.  With the addition of a handful of parts and a suitable power supply, this module will deliver 50W RMS into 8-ohm with 0.1% THD.  

TDA7294 Audio Amplifiers -  TDA7294 is a monolithic integrated circuit in Multiwatt15 package, with high output power (up to 100W) intended for use as audio class AB amplifier in Hi-Fi field applications (Home Stereo, self powered loudspeakers, Topclass TV).  Thanks to the wide voltage range and to the high out current capability it is able to supply the __ Designed by Popescu Marian

Telephone Audio Interface -  Audio from a telephone line can be obtained using a transformer and capacitor to isolate the line from external equipment.  A non-polarized capacitor is placed in series with the transformer line connection to prevent DC current from flowing in the transformer winding which may prevent the line from returning to the on-hook state.  The capacitor should have a voltage rating above the peak ring voltage of 90 volts plus the on-hook voltage of 48 volts __ Designed by Bill Bowden

Telephone Headset Adaptor -  Keep your hands free with this simple low-cost project.  It can be used with any phone that uses RJ11 modular plugs and sockets. __ SiliconChip

Telephone Headset Amplifier -  This circuit goes between a telephone and a headset.  The project has a headset cord and plug (cut from a cheap cell phone headset) on the input and a suitable jack on the output.  The speaker signal passes through this circuit, but the microphone signal is __ Designed by Andrew R. Morris

Telephone Line Audio Interface -  This device connects the telephone line to a home theater system or PA system (receiver only).  It is phone line powered and features automatic volume control (AVC).  It also mutest itself when a phone is picked up to prevent feedback. __ Designed by Andrew R. Morris

Telephone Test with Audio Mixer -  I have used this type of circuits for quick testing of telephone equipment.  This is a quick hack that does not exactly resemble the characteristics of the real telephone network, but is enough for this kind if applications.  If you want better simulation, change the resistor to 600 ohm and increase the power supply voltage.  And by the way you can also feed signals to telephone if you connect the circuit output wires to small amplifier output. __ Designed by Tomi Engdahl

The "Mighty Midget" Audio Amplifier Module  -  It's based on a Philips class-H audio amplififer IC and can deliver 36W RMS OR 70W music power, all from a 13.8V supply. __ SiliconChip

The 125 Theremin -  A Vacuum Tube Pitch Theremin

The 126 Theremin -  A Complete Vacuum Tube Theremin

The 144 Theremin -  An Improved Version of the Southwest Technical Products Model 142 Theremin

The 145 Theremin -  An Improved Version of the 144 Theremin

The 2006 Minimum Theremin -  An Improved Version of the Minimum Theremin

The 203 Theremin -  A Battery-Operated Version of the Wien-Bridge Theremin

The Beast-100 to 300W Push-Pull 3CX300A1 Amp! -  This project was inspired by a visit with Eric Barbour, Applications Engineer for Svetlana , in his Portola Valley, CA office.  I was in Silicon Valley on other business and decided to pop in to meet face to face.  Eric had, in the past year or so, been very supportive of my efforts with my Single Ended SV811-10 Amplifier.  During our conversation I mentioned that I tend to keep out of the mainstream when it comes to audio design.  This is what originally lead me to try the SV811 and SV572 types over the currently popular tube choices.  With that he handed me a pair of 3CX300A1 and said "Whadaya think you can do with these?!" __ Designed by Bob Danielak

The Big-E Stereo Parabolic Microphone -  This device is a stereo amplifier for a high sensitivity stereo parabolic microphone.  It can be used for listening to distant sounds.  Typical parabolic microphones are monophonic, this unit has a stereo audio path that helps produce more realistic sounding audio.  The Big-E can be used with headphones or as an audio source for a stereo recorder.  It can be plugged directly into a computer sound card's aux input. __ Designed by © G. Forrest Cook January 1, 2005

The DPA 220 : 100 W in 4 ohms-bipolar -  T1 to T6 create the input differential stage.  The D7 and D8 zener diodes stabilize at 5V.  These are just the simplest low-power zeners, only they have to be coupled in tolerance of 200 milivolts, which should not be a problem.  T1 to T6 are common all-purpose low-power transistors with high Hfe.  These six and maybe the next four have to be coupled in tolerance of 25%. __ Designed by Rysanek Frantisek

The DPA 330 : 170 W in 4 ohms-FET's. -  Now we're getting to the best stuff.  Let's discuss some parts: As you can see, the input stage is quite similar to the previous typesit was originally developed for this one.  There's only one new thingthe servo feedback amp OA1.  It subdues the DC voltage on the output below 1 mV.  The real news come in the power stage.  The fets are completely different than bipolars.  A problem is how to eliminate the gap causing crossover distortion. __ Designed by Rysanek Frantisek

The DPA 440 schematic -  Audio power amplifier circuit diagrams / circuit schematics __ Designed by Rysanek Frantisek

The DPA 880 : 400 W in 4 ohms-bipolar -  Again, this one is similar to the above ones, only it uses serial connection in the power stage to allow a higher voltage:  The bias current is 110 mA; The output coil is 14 turns of 1.8mm wire on an 11mm diameter;
The trafo should be about 2*57 Volts and 20 to 25 amps !!! __ Designed by Rysanek Frantisek

The Emperor's New Amplifier -  I spent much of 1997 designing and building my ultimate dream amplifier, which I named "The Emperor's New Amplifier"TM (TENA) for a quality it shares with the fabled emperor's wardrobe-- transparency.  It was also an oblique reference to the marketing hype that pollutes high-end audio.  I thought about commercializing it, especially when the lab where I worked announced it was shutting down, but I soon realized that marketing high-end tube amplifiers is not a reliable

The ESP SIM (Sound Impairment Monitor) -  The smallest variation in amplifier performance is shown with this simple circuit __ Designed by Rod Elliott  ESP

The GEM: Class-A//AB Amplifier -  The GEM is an audio power amplifier embodying simultaneously active Class A and Class AB output stages for 100+ Watts into a 4 ohm loudspeaker.  The front end pcb will drive up to 100+W variants, or the 200+ Watts version into a 4 ohm loudspeaker load. __ Designed by Graham Maynard

The JFET DoublerA Simple Screaming Octave -  This circuit is a follow up to the MOS Doubler (tm) that I did a while back. I did this one to test the supposition that if you generate a good octave by cancelling out everything except the distortion in a circuit, then you could get back the signal mixed with as much of the distortion as you liked by un-balancing the cancellation circuit.  Turns out that it works. __ Designed by R.G. Keen

The Leach Amp -  One amplifier builder found that the 2N5416 PNP transistors that he purchased were NPN.  I have tested them and verified this.  Two of the transistors are shown in the linked photo.  They are identified by the letters ON surrounded by a circle, signifying they are products of ON Semiconductor.  You can check

The Marshall 18W -  The Marshall 18W adapted for use as a distortion stompbox. __ Contact: holler @ runoffgroove.Com

The Miller Effect -  (spice design) __ Designed by Rick 

The Miller Integrator -  (spice design) __ Designed by Rick 

The Minimum Theremin -  A Very Simple Pitch Theremin

The PortaPAL Public Address System-Part 1 -  It's packed with features, is easy to build and rivals commercial systems costing much more __ SiliconChip

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Audio Amplifiers:   #'s       A - D        E - M        N - R      S - U        V _ Z

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