electronics-amplifier tutorial

The 70 watt amplifier circuit is pretty much original, and with a +/-35V supply as shown, will provide 70W into 8 Ohms quite happily. In its lifetime, many of the mods mentioned above were made anyway, since I could never find the circuit diagram when I needed it, so often made it up as I went along! It is a fair testament to the amp that all sorts of resistor and capacitor substitutions can be made, and it still works fine.

This amplifier is fairly well behaved for turn on, and should issue (at worst) the smallest click as power is applied. When power is removed, after about 5 seconds or so, there will normally be a low level thump - this is not dangerous to speakers, unless used in tri-amp and directly connected to the tweeters - DO NOT DO THIS - not with any amp. Always use a capacitor in series with tweeters (see Bi-Amplification, Some thoughts on Tri-Amping).