On 30/09/10 12:37, Adrian C wrote:
On 30/09/2010 01:40, The Natural Philosopher wrote:
Adrian C wrote:

It's not a MOSFET amp.

well I am not surprised it blew up. Pretty amateurish design.

FWIW I've found an old Maplin catalogue from 1985 with the original
project. (The days when the catalogue had projects and data sheets
printed inside that you could actually dream & build from!)

http://www.scribd.com/doc/38419958/50W-HiFi-Power-Amplifier-Maplin

First paragraph of that reads ...

"A superb quality 50W power amplifier. We threw away all our technical
specification handbooks and designed an amp that just sounded musically
perfect. When we'd finished we found that we'd got a pretty impressive
technical spec as well."


Yep. I remember that quote from the catalogue well. It gave me a mental
picture of some bloke beavering away in a Maplin back-room:-

Randomly assemble some components.
Flick switch - puff of smoke. Bugger!
Randomly assemble some components.
Flick switch - puff of smoke. Bugger!
Randomly assemble some components.
Flick switch - puff of smoke. Bugger!
Randomly assemble some components.
Flick switch - horrible noise, but no smoke. I'm on to something!
Make random changes.
Flick switch - puff of smoke. Bugger!
..
..
..


Mind-you, I still bought two kits.

Cheers,

Colin.