Saturday, March 05, 2011

ECC82 (12AU7) 12V VFO

Now that I de-freezed, on to work:
Found a nice article on a 12AU7(ECC82) vfo here, decided to try out the circuit using less lethal voltages (I had my fair share of electric shocks if you know what I mean).

Here's the prototype:

...admire the beautifull wiring work...and circuit...you can find a clear one in the article link provided above.



It works! The only hard part is to make the a coil for it. Mine was done with the cientific methot of trial and error...oscilates around 800-1200khz but I intend to make one for 5-5.5Mhz.

This was just a proof of concept but working with 12V supply and no buffer it can deliver about 0dBm measured from my NCY (Not Calibrated Yet) AD8307 power meter.

It takes a little to get into oscillation due to valve warming as you can see in the video:

video

Having time and a nice box to put it, looks like a nice little external vfo for one of my vintage HF radios....one of this days....

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