Thread: Early FM tuners
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Old 5th Jan 2005, 8:01 pm   #4
high_vacuum_house
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Join Date: May 2003
Location: Belper Derbyshire
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Smile Re: Early FM tuners

Hello there,
I think that the main idea of a seperate FM tuner unit with a power supply is that you diddn't need to buy a completely new radio reciever when FM was introduced. You connected the output to the gram connection on your existing set and then used the gram setting for FM. An output stage, volume/tone controls were not required on the tuner unit as these were on your existing radio. Without these components plus a smaller cabinet and power supply the tuners were fairly cheap compared to a new radio.
There were quite a few DIY kits avaliable, the best known one being by Jason kit. I have 2 of these bought at the same time at a radio rally. They are very simple to build and use a small quantity of components. I think a metal rectifier is used for HT and 2 semiconductor diodes are used in the discriminator circuit.
Thanks,
Christopher Capener
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