Re: Home brew TRF
Your HT voltage is way to high for a TRF. Most regenerative detectors operated with an HT of about 60volts or less (the output stage can operate at the usual voltages tho), you might find that you have difficulty controlling the reaction or get microphonics and other undesirables.
Remember that too much reaction can turn your receiver into an effective transmitter and that the humble 6J5 can run upto 2.5 watts input!.
As for controlling the reaction by dropping the HT, I don't think thats a scheme usually used even in very early sets. With triode detectors, the usual method is either to use a small adjustable link winding over the main tuned winding, or via a small (say 150pf) variable from the tuned winding to anode.
The majority of 30's TRFs used a screened grid (tetrode) or small RF pentode for the detector, the screen voltage being varied to control the gain.
You really don't need to use reaction at all these days, one decent stage of RF amplification followed by a detector and output stage is all that is needed. With broadcast stations putting out 10's (or even 100's) of Kilowatts, you really don't have any difficulty receiving them even if you've got a mediocre aerial.
On the plus side, TRFs are great fun, they are simple to work on and can work well plus the sound quality can be superb (at least I think so) in a well designed set.
Good luck with your project
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