diy IF transformers: first attempt.

[Amie]

Hi Folks, why not go to the PCC84 as used in TV, it was a good reliable valve and seems to have had less problems than the ECC85, which got a bit of a bad name.
You could also go further and look at the UHF tuner valves PC86/88/97/900. Slightly odd heater voltages and only single valves but most electrodes are double pinned on the base for low inductance.
Also plenty around and really cheap

Ed

Hi Dr Ed.

I think the Brimar 7AT7 that I have a couple of new examples is an equivalent of the PCC84, good valve and little interest from the tube rollers. One of the more successful superregen circuits I tried used an PCF80 and PC97, pentode section of the 80 for RF amp/aerial isolation, 97 for SRA, triode section of the 80 for AF ... May seem odd but took a step away from instability caused by using multiple section valves for the SRA.

One of the things I found that I had to get my head round was that the superregen self quenching circuit is an amplifier that efectivley produces a pulse position modulated output: including a tailor made AF stage that discriminates that signal makes for a much more successful AF receiver...