I put time into build IOT and testing network things – and it took me down that pathway of electronics and general abilities. So it lead me to DIY audio – amplifiers, pre-amps etc.
Since I went down that track it became a bit of a passion and now I want to share some images I made for a forum. So I’m loading them up here. This is a work in progress and having these images helps me link to them.
This amp, so far has 3 TDA2030 chip amps … 2 work as a bridged unit with a sub woofer filter. I can fade in extra bottom end as you would – that is via a speaker box I made with a 40 watt speaker. Much of this is recycled wood or speakers and the electronics are all kind of hand made proto-type boards with a lot of point to point wiring.
This is a side view
Front left is the pre-amp with bass and treble, balance and volume … there is a mono-mixer and master volume but its a bit off the edge of the photo. That mid right side block of metal is the mono-top/mid box amp. I will replace it with a dual amp for stereo later. For now it sounds very nice in mono and who cares because its on the wall and i’m not sitting in a place where stereo really matters or works.
Its modular –
I started by bolting a transformer 15 – 0 – 15 for negative and positive rail power. Thats in the back corner with an EPS sticker on it. Then to the left it gets filtered with a fill wave rectifier and 2 10000 uF filter caps – one per voltage rail ( negative 15 to 0 and 0 to 15 positve). That produces about 20 peak voltage of DC which will sag to about 18 under load. That goes into a positive and negative voltage regulator that can be varied. In the top-left side. Out of that comes fairly clean power for the 2 amps and the pre-amp that all require twin power rails. The sub is about 40watts and the top/mid amp is about 20 watts. The transformer should supply about 90VAC if you measure it at +/- 15v thats 30v by 3 amps. The voltage regulator has some very small bypass transistors to beef up the current to 3 amps if needed.
There are LEDs that pulse with the current draw due to some resistors that create a voltage drop before the voltage regulators. That voltage drop triggers the transistors to activate and open up like a switch for more current.