1 tube regenerative *and* reflexed?

[Circlotron]

Everybody that has been around radio for a while has probably built a regenerative set at one stage. And back in the valve/tube days some radios had a reflexed IF stage where the demodulated audio was fed back into the IF stage to get some “free” audio amplification as well.

What I’d like to know is, has anyone seen any details of a single tube radio that uses both regen *and* reflexing? The idea being to get the absolute most out of a single tube. 

Edit -> found some references on google but can’t delete this thread.

[bob91343]

That could work only if you stay well below the threshold of oscillation.  Else the audio would be terribly distorted, with whistles and clipping.  If you apply just a few dB of positive feedback it might work.

[oPossum]

Double reflex radio repair with circuit explanation

[T3sl4co1l]

Regen or superregen?

I don't know that regen is all that useful, feedback needs to be tuned perfectly and it's awful at reception and distortion and etc...

Superregen is out, it's specifically nonlinear.

Perhaps if one could devise a way to use external limiting (diodes, saturable reactor?) to reproduce the nonlinear dynamics of superregen, so the amplifier can remain linear, it could work.  Hmm, that'd be a challenge.

Tim

[vk3yedotcom]

Maybe this is cheating, but consider using a dual tube like a 12AX7 (triode + triode) or 6BL8 (triode + pentode).

The first section could be an RF preamp (useful for isolating antenna from regen detector).

Second section oscillating detector.

Audio from that could be fed back into the first section which does double duty as an audio amp.

Haven't built it so can't confirm it works.