Sony home theatre – Reworking the surround amplifier for stereo use

Rear Surround Module - Sony KM7

Making the most of 7.1 or 7.2 with the extra surround channels in a Sony

Most home theatre amplifiers have 5 active channels and one dedicated low frequency pre-amplified output for driving an active sub-woofer.  Sony amplifiers for the consumer often has extra channels which are on a daughter board designed to drive up to 100W into an 8 Ohm load. These are the ones the DIYer should be on the lookout for. In a previous column I mentioned that these can often be picked up for about R100.00 in faulty condition. Continue reading “Sony home theatre – Reworking the surround amplifier for stereo use”

Light Control – the DMX system

From LED flashers to DMX Lighting

Programmers starts with “hell world”. Beginners in electronics start with light flashers.  Arduino does too! Although we boast about this being an analogue sight be mindful of the fact that digital is with us and won’t go away. It has made things smaller, faster and more accurate.  Audiophiles don’t like the nasty little bits (pun intended) added in between but high end ADC and DAC chips really make a difference.  So we have this great sound system and now we want to party. Ever party without lights?

For the younger generation

Amplifiers, loudspeaker and loud music has always been around,  but lighting was primitive. Lights were manually controlled, sometimes by servo but the local church hall definitely did not have this – we had the coffee can approach, lowering, tilting and panning all done manually by possibly using draw wires or some or other trick. Digital?  Bah, that was for sissy’s.  Along came the heady 80’s and of course this was also around the time that manufacturers realised that a computer could be used for other things besides arithmetic and nuclear tests. This also around the time that United States Institute for Theatre Technology (USITT) wised up and cracked the code.

Chauvet Helicopter Q6
The popular Chauvet Helicopter Q6 – DXM controlled lighting display.

Before moving on I suggest you have a look at the Grateful Dead’s “Wall of Sound”, a marvel at the time and boasting the best sound system in the world. Have a look at some of the image files and think of what this might have looked like at midnight without any stage lighting? Continue reading “Light Control – the DMX system”

Amplifiers & Light Control

Autona 125W 4 Ohm

Mixing loud music with a light show

Pink Floyd and Electric Light Orchestra, music enhanced by the control of light.  What is great powerful music without a visual experience.  Not Ozzy Osbourne biting a bat or dove’s head off of course but something more appealing, sound to light, chasing, strobing and laser. Of course it’s every young inventor’s dream to build their own dazzling light show but where to begin?

Autona 125W 4 Ohm
Autona 125W 4 Ohm

Sound amplification:

Sound or audio engineering is not just a profession but an art….. exactly the same applies to an engineer who spends his life building top quality audio amplifiers.

40W Audio Amplifier - Quasi Complimentary
40W Audio Amplifier – Quasi Complimentary – More Information below

Audio amplification is split into two parts (1) the voltage amplifier or pre-amp. This amplifier has a number of pre-requisites:  being able to amplify a tiny signal like that from a microphone or turntable (with RIAA equalisation),  being able to boost the bass or treble or equalise the signal for different room parameters (stage, hall etc) and (2) the power amplifier, which takes this signal and amplifies it further to feed a loudspeaker.  All pretty simple, right? Continue reading “Amplifiers & Light Control”

Oscillators, amplifiers, light control

Chapter Two – Some more stuff… oscillators, amplifiers, light control

Who said oscillators aren’t interesting.  Considering it’s the very foundation on which all digital electronics is based it must be.  Think of the extremely powerful desktop computer, that laptop or tablet – it all begins with a train of pulses called clock-pulses. And how did that all start?  With an oscillator of course.

Parallel rod push-pull 120MHz oscillator
Parallel rod push-pull 120MHz oscillator.
Retrieved October 12, 2014 from W. W. Smith, ed. The Radio Handbook, 5th Ed. published by Radio, Ltd., Los Angeles, 1938, p. 427, fig. 23

And then we have amplifiers. What exactly is an amplifier?  An amplifier can be used for many things and strangely enough although we see and hear about audio amplification many people aren’t aware that we have amplifiers for light, microwaves, radio, we even have a thing called a magnetic amplifier.  But all amplifiers serve one purpose – to amplify a small signal into a huge or even a ginormous one.  LASER – Light Amplification by Stimulated Emission of Radiation. How about MASER – Microwave Amplification by Stimulated Emission. Continue reading “Oscillators, amplifiers, light control”

A Career in Electronics – Beginning the Sequence

Fluke 117 - R7000 to R8000 in South Africa

In the beginning Steve, Steve, Bill and Paul had an idea….

Part I of the basics to electronic engineering… for the student

Many years ago most schoolboys had this desire to build something great to make them famous. It may have been a steam train, a car or an aeroplane.  Girls didn’t talk about this because it was “boy” stuff.

DSO 528

Times changed and so many boys went on to build electronic stuff, flashing lights, crystal receivers and audio amplifiers.  Some girls tried this and to the young boy’s embarrassment, were better than them.

Many years after this along came Steve Jobs, Steve Wozniak, Paul Allen and Bill Gates.  They built and programmed computers and became multi-billionaires. Many boys and girls went on to become programmers, their soul pursuit was becoming rich and famous, unlike many Electronics entrepreneurs.

But this article is about electronics. Something which without the two Steve’s, one Bill and one Paul would never succeed. Continue reading “A Career in Electronics – Beginning the Sequence”