Friday, December 22, 2006

Partygram!


So much for the 6BW6...along came...Solid State Technology! Yes! Transistors!

By this time I was working as an Apprentice at Telefusion Ltd on the front line of Technology. So my next project was to improve the original Stereo amplifier and bring in Solid State Devices (Transistors) My friend Neil had just built a slimline amplifier based on an amplifier in Practical Wireless, the Partygram.

The Partygram was a Mono Amplifier that used two high power transistors (AD161 and AD162) in Push-Pull Mode to give an output of 10 watts rms. Two of these amplifiers built in the same box would give high quality stereo! I was dead impressed with Neil's Amp, so I set about building one myself. I managed to obtain most of the parts from work, but the most expensive item was the mains transformer. The drivers and pre-amps used BC108's and equivalent PNP devices. I built a case from aluminium and my Dad built a wooden surround, all the controls were mounted on the front. This was a superb project, we could have audio separates (Amplifier, Deck, Speakers) and was used at home and later when I got married right up until about 1980 with a pair of wall mounted Bush Denon Speakers (actually Warfedales)

Later, I used the case of the amp to house another amplifier, a FET 100 watt disco amp from Maplin which to this day is still used...in fact I used it yesterday at school for the Christmas Disco!

I still have an original copy of Practical Wireless with the Partygram circuit and details, how sad am I?

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