gres
Full Member level 4
It’s a garbage project. I even didn’t buy a condensers.
Two perun endings in bridges conection, powered from transformer 0,4kW. Filtration about 42000uF per power branch. Speaker needs a lot of watts that’s why I made big capacity. Except rebuilt power amps into bridges, I made some power changes. There are two pares of 2SC5200 and 2SA1943.
Each pair can hold 100W/4ohm. Boards are one above the other, situated elements to each other. Thanks to that inside the casing is a lot of space and a lot of air. A lot of “fun “ I had with secure system. But results are very fine. I made some tests – 8 ohm resistor can boiled glass of water, before resistance wire die. Big toroidal transformer have bed influence on my house fuse. That’s why I made soft start.
Thin board consist 4 resistors with common power – 200W and resistance 20 ohm. They can be shorted by relay that is powered by nontransformer power supply. Power ending needs some delay, other ways it start with loud LUUP.
A standard transistor with RC that control the coil. Power is no-filtered so it disconnect soon after turn the power off ( ending plays from condensers) so both “start” and “stop” is just a silence “bip” sound.
Volume regulation – potentiometer. It’s connected with ball by brass bar.
Wires are tied by some cable
Here you can find interesting detail – small thing that can power all device. True is that this STX can work with much more watts, but is enough for me.
Hard sound of STX + quite food control as for such a small amplifier.
Original text at https://www.elektroda.pl/rtvforum/topic1552874.html