16-08-2021, 05:00 PM
Thanks. I had considered the PL 84 once before but was warned there wete differences. But then it is possible to buy reasonable quality new ones of the EL84 for around £10. P valves are a bit of a challenge but some are worth the trouble powering the heater. I've a guitar amp for instance that has a pair of PL36s for output. (25v heaters ?)Magic....if you remember not to buzz test the top caps with your finger 
The reason I asked in this instance is that I was just sorting through some junk and found a vhf tuner adapter, I was investigating its insides and realised it was a little super regenerative circuit, something that I always find interesting, but it was sans valve. The connections seem to match up with the ECF80, which would be period correct @1955 by the date stamp on the "tin enclosure" though I'd only got the 30C1 here to hand, (I'm at a friend place...) It works! Sounds a bit muddy but its quite sensitive...
The reason I asked in this instance is that I was just sorting through some junk and found a vhf tuner adapter, I was investigating its insides and realised it was a little super regenerative circuit, something that I always find interesting, but it was sans valve. The connections seem to match up with the ECF80, which would be period correct @1955 by the date stamp on the "tin enclosure" though I'd only got the 30C1 here to hand, (I'm at a friend place...) It works! Sounds a bit muddy but its quite sensitive...
