As a young (or old) student it takes some time to get one’s head around the design idiosyncrasies of solid state amplifiers. Truth be told many of us found tube nomenclature and circuit design easier to comprehend than anything that followed “hole” theory. Big bad things come to an end and eventually we found it easier to crib other designs.
To kick off, and this is a response to forum user “Roggies” request for a schematic for a budget quality tube pre-amp for MC cartridges.
Unfortunately MC never has a cheap solution and that’s the bottom line. MM may be getting better but phono die-hards are still going to have to dig deep if they want to belong to the elite.
We won’t get into a debate about which is better, tube or SS but on a spec level there are some incredible op-amps around which do an incredible job to amplify low level signal from vinyl but of course we have the tube purists. Continue reading “The importance of RIAA”
Class D amplifiers and drivers are becoming so popular that some of the largest IC manufacturers are no longer focusing on class AB or A driver chips. This is certainly the case for TI and sub group National Semiconductor. Of course some of us don’t like class D. What about our firm favourites: LME49xxx series or the LM4702? Continue reading “National Semiconductor – LME49811”
There is a lot of theory put into amplifier design and when one looks at these complicated circuits often the protection circuits are more sophisticated than the gain stages. Purists believe the only true amplifier is a piece of wire with gain. Engineers often criticise the protect circuits of creating their own problems, along with causing inferior quality reproduction.
These are the major problems come across in the design of any amplifier:
Heat – is there sufficient cooling for heavy duty work?
Can the output transistors go out of their Safe Operating Area? (known as SOA).
Can the amplifier drive a 2 Ohm load when minimum load spec is 4 Ohm?
The dangers of mains voltage boosting and sagging?
Oscillations and instability.
Over driving and distortion.
Loudspeaker protection – expensive lessons to be learnt.
The Sziklai, like the Darlington is a very high current gain device.
After dabbling on a few pages about Darlington transistors, what about the pseudo Darlington, the compound feedback pair, the Super Transistor, the Sziklai stage. (in some of the images Sziklai is spelt Ziklai – apologies for this)
So now you have purchased or built your own desktop DMX lighting controller, what next?
The 1970s glitz and glamour model
If one looks back to the 1970s and the disco scene there was a lot of glitz and glamour to spinning mirrors, strobe lights, colour organs and mood lighting in general – don’t forget the silver jackets. UV or black tube magic was very popular. Don’t forget the gorgeous girl with dark underwear. This was all just very kitch. Nowadays “clubbers” wouldn’t be seen dead in a place that sported such grotesque lighting but do bear in mind this was just a phase mom and pop went through. Coming into the millennium there were some surprises in store: 3D laser – holograms, motor driven lighting, pan, tilt, high powered strobes (we had that one before) – all controlled from one interface, either software driven from your computer or a free standing light mixing console.
Some real work for the Arduino and Pi – DMX Lighting
In a previous article we briefly touched on DMX lighting – Light Control – The DMX system . Lighting control has been with us for eons and where there is sound there should always be light, right? But first things first.
The DMX controller is very versatile, modern units have large memory reservoirs to control lighting automatically for almost every theme and scene. Smaller units are available for the DJ scene and pack the power of old analogue lighting controls used for supergroups years back.
Most audio equipment at home draws very little current from the mains supply. As we go up the pecking order we have amplifiers which can draw in excess of 20A from 220V which usually attracts the neighbours and police and then we have the juggernauts, arrays being driven by over 100kW of power amplifiers. Sound like a lot of power? Well, think of the light show. Continue reading “How DMX Intelligent Lighting works”
Although SEO is all about well written material sometimes we do need to veer off this patch of oasis and not re-invent the wheel. Audio circuitry, your own equipment, testing, listening and boasting is all part of the job. Here we list some awesome websites which should get your own creative juices flowing.