Several people have requested that I set up a web page with construction details for the second of two power amplifiers that I published in Audio magazine. This amplifier is the monophonic 270 watt Double barreled Amplifier. For the original article, I specified plus and minus 85 V dc power supply voltages. The voltage can be increased to about 93 V to obtain a power rating of 300 W...

The simplified circuit [Fig.2] shows that each sub-amplifier consists of two voltage gain stages. The first stage consists of a complementary two stage common emitter [Q1-7] whose gain is about x2.3. The second stage is a current mirror stage [Q13-14] which drives the voltage across a load resistor tied to 0V...

This simple audio power amplifier was originally designed for a circuit board workshop, conducted by the OSU IEEE Student Group. At the workshop, 20 participants each constructed this amplifier, by etching and drilling the single sided circuit board, soldering all components, and attaching a pre-built heatsink assembly with the output transistors. Three workshops were held between 1995 to 1996...

A medium power amplifier that is characterized by a lot of good sound quality, but simultaneously is very simple in the construction. Him uses, enough time in my active loudspeakers. In his output stage exist the very good FET transistors, technology HEXFET, transistor which are controlled by voltage and no by current as the classically bipolar transistors...

An amplifier to drive low to medium impedance headphones built using discrete components. Both halves of the circuit are identical. Both inputs have a dc path to ground via the input 47k control which should be a dual log type potentiometer. The balance control is a single 47k linear potentiometer, which at center adjustment prevents even attenuation to both left and right input signals...

The circuit use one simple, but good power supply, is enough its armor-clad by the remainder circuit, if it needs, with a aluminium, so that we avoid the noises. All the circuit can be placed in a small box, from which will only come out the RCA jack, the main power cable, in the back box part and the Diode Led D1, in front part. Good its are placed a Fuse and a good small switch. The signal from the circuit outputs, with a good cable, is led to a free LINE input of amplifier or preamplifier. If the output signal level, is not that we want, we can change the resistors R9-22, with other value so that we adapt the level...

This circuit is mainly intended to provide common home stereo amplifiers with a microphone input. The battery supply is a good compromise: in this manner the input circuit is free from mains low frequency hum pick-up and connection to the amplifier is more simple, due to the absence of mains cable and power supply. The circuit is based on a low noise, high gain two stage PNP and NPN transistor amplifier, using DC negative feedback through R6 to stabilize the working conditions quite precisely...

The transmitter was designed with redundancy and cutback (reduced power mode) in mind, giving the transmitter more continuity of service. The final amplifier was divided into 3 separate modules, each using four RCA type UV-898 tubes in push-pull parallel making up a total of 12 output tubes. The outputs of the three modules were combined in series in such a way, that if one of the 3 RF modules failed, the transmitter could continue to operate using the other modules. This idea was a very important step in transmitter design as modern solid-state transmitters are designed entirely in this a modular fashion as is described in my WABC Digital AM Transmitter Page Digital Modulation Section. Modern transmitter with modular design are composed, typically of 1KW modules with lower power modules used for shallow slopes of modulation...

The Clock Controller was designed to be an exemplary of using 'C' language to control timer0interrupt, 7-segment LED and keypad scanning. It provides 1-bit sink currentdriving output, for driving a relay, opto-triac, say. Many projects requiring7-segment display and keypad interfacing may get the idea from the Clockcircuit and software...

Audio-taper pot, R1, adjusts input level into two LM386 amplifier chips. The LM386 is a low-voltage audio power amplifier, designed to operate on 4V to 12V. It has an internal 15K feedback resistor between pins 1 and 5 which would set the gain at 20 (26dB)...

Free energy Bicycle lights

This bicycle safety flashing light system is based on a newly invented electrical generating system, NO battery needed, No friction on any parts of the bicycle. No drag. get the energy almost free (at least on bicycle). Very bright. Standby light...

High Quality Valve Amplifier

In recent years more and more, have a tendency ket demanded higher reimbursement structures with lights and music lovers in general and manufacturers of tube amplifiers. The reason, in their view is that the sound of tubes is more sweet, how rich and incomparably cleaner, On the other hand, however, the entire structure is much more massive than transistor amplifiers, considerably more expensive, while the operation voltages are very high that require special protection measures to prevent identity risk of electric shock. The tube structures as key components require fine-tuning, otherwise liable to break. The lights generally resistant but excellent work at very high temperatures without having the need for heatsinks. They just need ventilation. The lifetime of the bulbs is probably less than that of a transistor but it does warn the iote be burned as opposed to transistor destruction is sudden...

Anti-RF filtered power supply 12-14 Volt / 3A

This power supply is dedicated for use with rf equipments like, linear amplifiers, transmitters, receivers, and in every application that clean an-noisy signal is required. The circuit is very simple and you can drive it with a 220V/18V/3A transformer at the pins 1and 2...

0-60sec start-stop timer with 555

This timer is ideal for small aplications. Due to its simple structure, its usage and nevertheless its universal character, this mini timer is usable in the most current applications needing time intervals, from some seconds through approximately 60 minutes. By simple modifications it is possible to adjust the maximum time and the timing scale, as necessary. A strong output, made by a relay, permits to adapt, on the input and the output, whatever apparatus...

16 bit Analogue to Digital Converter LTC1052

The circuit here is a A/D converter, that consisting of A2, a flip-flop, some doors and a current sink, is based on a current balancing technique. Again, the stabilized LTC 1052 50 no drift of V input 1 ° C is necessary to eliminate the offset errors of aid. ..