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Amplifier Circuits:  Power Circuits
Power Amplifiers:  #'s - C        D - K        L - P         Q - S        T - Z

Amplifier -- Main Page

Last Updated: June 02, 2021 01:44 PM

Circuits Designed by Dave Johnson, P.E. :
Band Drummer’s Microphone Switch   -  I received an email from guy who plays drums for a small band.  He wanted a simple way to turn on and off his microphone with just a tap of his drum stick onto a small box.  The circuit below performs this task with the aid of a piezo device as a shock sensor and a small dual coil latching relay with two sets of contacts.  The contacts can be wired any number of ways to a microphone circuit . . . Hobby Circuit designed by David A. Johnson P.E.-October 16, 2011

Broad Band 2Mhz Optical Fiber Receiver   -  if you need more sensitivity than the above circuit this circuit provides about ten times more gain.  It too is designed around an inexpensive plastic optical fiber detector . . . Circuit by Dave Johnson P.E.-June 09, 2000

Broad Band 50Mhz Optical Fiber Receiver Version A   -  if the above circuit it still too slow, you can try this circuit.  What it lacks in sensitivity it makes up for in speed.  The circuit attaches a plastic fiber optic PIN photodiode assembly to a small box containing a small 3v battery and a standard . . . Hobby Circuit designed by Dave Johnson P.E.-June 04, 2000

Brownout Voltage Tester   -  I used this circuit years ago to test AC line powered devices under 95vac line voltage conditions.    it has a rating of 250 watts.   . . . Hobby Circuit designed by Dave Johnson P.E.-July 11, 2006

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

Band Drummer’s Microphone Switch -  I received an email from guy who plays drums for a small band.  He wanted a simple way to turn on and off his microphone with just a tap of his drum stick onto a small box.  The circuit below performs this task with the aid of a piezo device as a shock sensor and a small dual coil latching relay with two sets of contacts.  The contacts can be wired any number of ways to a microphone circuit . . . Hobby Circuit designed by David A. Johnson P.E.-October, 2011

Bass Guitar Amp -  I've been wanting to put these EL509's to use!!! Figured a nice high-power bass guitar amp would be a perfect application.  I have the amplifier built to the point shown in the schematic, above.  Initial testing with tone-stack replaced with a 10:1 voltage divider is very promising.  Still need to decide on the tone stack arrangement.  The unit is built as a stand-alone head, and will be used with a Peavey 15" + 2x 10" Bass cabinet __ Designed by Bob Danielak

Birdie Doorbell Ringer -  P1 is of experimental value.  Start with 220 Ohms or so and modify to suit your needs.  The transistor is a general purpose kind and is not critical, almost any PNP type will work.  L1 is a bell-transformer which is usually already present in the house.  If you wish, you could use a battery instead of the bell transformer.  Just hookup a 9-volt battery   (or wall adapter) to points 'A' and 'B'   (A=+) the diode   (D1) is to protect the circuit from accidental polarity reversal and is optional, but required as a rectifier for use with the bell transformer __ Designed by Tony van Roon  VA3AVR

Boogie MkI adapted for use as a distortion stompbox -  One of the first amps to offer distortion at lower volumes was the Boogie MkI amplifier.  As told by Randall Smith, the designer of the Boogie amp, these amplifiers were born of a practical joke on a guitarist friend.  Mr.  Smith modified a Fender Princeton to have considerably more gain and power, but appear stock.  As the story goes, Carlos Santana play-tested the amp and was impressed.  Carlos was quoted as saying the amp "really boogied!" Thus, the name of the amp was born. __ Contact: holler @ runoffgroove.Com

Book PC MP3 Player -  A small computer running Linux with 12 volt power supply and wired remote control makes a great sound system for a car __ Designed by Bob Blick

BookPC Car MP3 Player -  This is an earlier player using a conventional PC motherboard, so the power supply I designed is quite compatible. __ Designed by Bob Blick

Britannia -  An original overdrive inspired by the Vox AC-30 Top Boost amp. __ Contact: holler @ runoffgroove.Com

Broad Band 2Mhz Optical Fiber Receiver -  If you need more sensitivity than the above circuit this circuit provides about ten times more gain.  It too is designed around an inexpensive plastic optical fiber detector. . . Circuit by Dave Johnson P.E.-June, 2000

Broad Band 50Mhz Optical Fiber Receiver Version A -  If the above circuit it still too slow, you can try this circuit.  What it lacks in sensitivity it makes up for in speed.  The circuit attaches a plastic fiber optic PIN photodiode assembly to a small box containing a small 3v battery and a standard . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Brownout Voltage Tester -  I used this circuit years ago to test AC line powered devices under 95vac line voltage conditions.    It has a rating of 250 watts. . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

Brute Force Marries Controlled Speed -  Linear Technology AN133 __ Designed by Jim WilliamsOct 12th, 2011

Buffer switches analog or digital signals -  30-Mar-06 EDN-Design Ideas Use an op amp and a dual SPST to switch signals under digital control __ Designed by Liviu Pascu, Kepco, Flushing, NY

Build a MIDI Drum Kit -  This do-it-yourself MIDI drum kit can produce just about any musical sound you can think of, either via a computer or a synthesiser. __ SiliconChip

Build a MIDI Drum Kit Part 2 -  Last month we introduced our latest MIDI instrument, the MIDI Drum Kit offering a staggering 546 drum sounds and not a stretched skin in sight! Here's all you need to know to put the control unit togetherand it's not that difficult __ SiliconChip

Build a MIDI Drum Kit Part 3 -  PART 3building the sensors and stand __ SiliconChip

Build a MIDI Keyboard -  Build a PIC based DIY midi keyboard for under $30 and by using free VSTs   (virtual instruments) you get a powerful music creation system

Build a Stereo Synthesizer -  There are many ways to create a stereo effect.  If you were miking a piano, a string section, or some other large sound source, you'd probably stick up a pair of directional mikes and assign them left and right.  But what if you want to "enlarge" a lead vocalist? Or, how about other inherently mono instruments like an electric guitar or a synthesizer? Well, you could delay one side or use a Harmonizer or some other related gadgetry, but generally with this method the stronger the effect you create, the more you'll jeopardize mono compatibility.  A short delay will cause phase cancellations in mono, while longer delays can create a disturbing slap echo. __ Designed by Ethan Winer

Build a Theremin for a Really Eerie Sound -  You wave your hands around mysteriously to play it. __ SiliconChip

Build an Adjustable High-Frequency Notch Filter -  02/06/03 EDN-Design Ideas Although you can obtain universal, resistor-programmable switched-capacitor filters that are configurable as notch filters, most cannot operate at bandwidths higher than 100 kHz.  Further, the typically 16- to 20-pin packages do not include a continuous-time, antialiasing filter to prevent spurious signals from appearing at the output Design by John Ambrose, Mixed Signal Integration Corp, San Jose, CA

Build the Bass Blazer -  It gives a visual readout of the bass signals from your home theatre or car stereo system on four bargraph displays __ SiliconChip

Build Your Own Ball Bearing Beat Box -  Ubercool light show for any DJ. __ Contact: Jameco Electronics

Build Your Own Compact Bass Reflex Loudspeakers -  Would you like to build some high quality speakers and don't mind doing some enclosure assembly finishing? These M6 compact bass reflex systems from theloudspeakerkit.com could be just what you are looking for.  Use them on stands or on a bookshelf. __ SiliconChip

Build Your Own MP3 Jukebox Pt.1 -  Here's a fantastic way to play your MP3's.  It's based on a PC and features infrared remote control and an LCD to display track titles. __ SiliconChip

Build Your Own MP3 Jukebox Pt.2 -  Play all your favourite music by remote control __ SiliconChip

Building a Champ guitar Amp made out of Junk Parts -  As you see from the above circuit, this is a fairly simple circuit and take note that this one uses a tube rectifier in the power supply. __ Designed by Jon Tirone, AKA John Fisher

Building a Musical Sunrise Quartz Alarm Clock -  For the past twenty years, I’ve been using an LED digital alarm clock-radio   (which I won as a door prize at a model airplane gathering in 1995) to wake up in the morning.  In recent years, I’ve found that the large glowing red digits disturb my   (and my wife’s) sleep, and felt it was time for something new __ Designed by Stepan Novotill

Building the Ultimate Jukebox -  Last month we looked at what we wanted in the Ultimate Jukebox.  Now let's start building it __ SiliconChip

Building the Ultimate Jukebox; Pt 1 -  In the days of IPods, MP3 players and all manner of fit-in-your-pocket, "music on the go" devices, why on earth would anyone want to build a freestanding jukeboxwhich, by definition, is almost a piece of furniture? __ SiliconChip

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