Regenerative reciever

Ah, I guess Vcc should really be B+...:)

No suggestions, but full marks to you for having the audacity to recreate this ingenious and much under-rated configuration. Respect!

Your aerial circuit is very low q. That will kiill performance. There seem to be various unnecessary bits too.

NT

Drop a note here,

Lots of regen knowledge there.

Mikek

On a sunny day (Sun, 29 Nov 2015 11:28:19 -0500 (EST)) it happened bitrex wrote in :

No, may even work, even your antenna is isolated from it I think, so should not radiate that much.

Why the transistor? Current source more gain? Ri of triode is low, should not help a lot?

Active load for the triode hopefully. High impedance at RF, but low at audio.

Thought it might be an interesting experiment instead of an RF choke...

What's this transistor thing hanging in the triode plate? If you're going to do it with a tube, use ONLY tubes. You don't really need the pentode section in the loop to provide regeneration. It can be done with just the triode section, leaving the pentode available for audio amplification. Something like this:

Some schematics and designs to choose from:

Somewhere in my junk pile is a 45 MHz super-regenerative slope detecting FM receiver which I build in the 1960's using a 12EC8. It's one of the few tubes that would work at VHF frequencies with 12V B+ power. It was the prototype of a police motorcycle helmet radio. It worked, but wasn't quite what they expected. I'll see if I can find the carcass and schematic.

I don't have an LTspice model for the 12EC8 but this might help build one: (5:39)

Ha! Norm Koren. A very cool guy (though I'm not a tube-head. We use his Imatest software in the lab). The 'Loose screws' story on his audio page is hilarious.

-RS

I hadn't heard that one before, but knowing the nature of some audiophiles, I can believe that it's possible. However, from my RF experiences, "tighten the loose screws" means tighten down the compression trimmer capacitors, which wrecks the tuning and alignment. It has happened because I convinced one of my former friends to do it. Knowing how things really work is a decided advantage when playing practical jokes.

I'm rather surprised that audiophiles are running SPICE models on their tube equipment. I've always suspected that they have a fear of numbers and repeatable tests, preferring instead to use perceptual and emotional criteria. I demonstrated that long ago with my ambience and presence meter, and was (temporarily) taken seriously.

I think you're Muntzing it too much. Put some components back in there! My general impression of regenerative receivers is that because you don't have many active components, you need to make sure that your passives are top notch or you get shoddy performance.

I'd go ahead and put a tuned circuit on the antenna side. If you're using the triode to isolate the antenna from the rest of the rig, I'd use it as a grounded-grid or grounded-plate amplifier -- either one should isolate in from out better than what you have.

(Sigh.) Yet another grey on grey "drawing"...

No... use grounded plate and Vee...

I demonstrated that long ago with my ambience and

Oh boy! I would have loved to be there and observe that demo!

Some guys I knew used to get "The Abolute Sound" magazine, and were mild audiophiles. We used to laugh at some of the totally insane stuff in there. I seem to recall an item by Enid Borbeley about interference coming up the air hose on her air bearing turntable and corrupting the sound. She recommended grounding the air hose.

Jon

The demo was a flop, mostly because nobody was paying attention to the demo, but instead were arguing with each other over whether ambience and presence actually existed and was worthy of measuring. The equipment worked, but experts would have none of it, especially from students. I think it was about 1968, while I was still in college.

At the time, there was no clear definition of presence. I had read somewhere that it was the sound quality of an empty room or stage. So, my meter measured background noise. Essentially, it was a modified General Radio sound level meter with some extra gain followed by a differentiator driving a meter amplifier. You could measure the background noise level on the GR meter, and the degree of change on the added meter. Incidentally, I still have the original GR sound level meter buried somewhere. Something like this:

I kinda missed with my definition of ambience. I thought it was a measure of reverberation. I generated a "click" (pulse) and measured how many returns could be seen on an oscilloscope.

Since then, ambience and presence have been fairly well defined: but during my demo, it was akin to witchcraft.

In early college days, I worked for a h-fi store selling ummm... hi-fi equipment. I've posted a few anecdotes in the past, so I'll skip the horror stories. The interesting part of the experience was discovering how much money was being spent on what I considered useless home audio devices and components. I had always assumed that the objective was to produce the best possible sounding music. Nope. The real objective was to spend more money of the stuff than one's friends, neighbors, and business associates. The critical moment, where it all came together, was the next party. The host would show off his new hi-fi system. Someone would ask what it all costs. The answer was intended to impress everyone present, who later ran out and spent even more money on the hi-fi stuff. Like all such pyramid schemes, eventually one would be expected to run out of money, but I haven't seen it happen yet.

Fast forward 40+ years, and found myself dealing with one of these: You don't know what expensive can be until you've seen one of these smarthome systems. Hi-fi is a big part of the puzzle, but there's plenty more to help empty the bank account.