[HBR] Regenative receiver question - audio choke

[hbr@mailman.qth.net]

HI,  I think choke vs resistor has to do with tube gain, supply voltage 
and coupling impedance to the next tube.  With a choke you get higher 
plate voltage than resistor so you have to bump the b+ up to get as much 
out of the tube.  As tubes became better and pentodes became more common,  
the shift went from choke coupling (L and C) to resistor coupling (R and 
C).  I think it all depends on how good your tubes are and how much gain 
you have to get out of the coupling (or how much signal you can stand to 
lose in the coupling).  Some of the coupling chokes were around 1000 H,  
low current of course.  The SW3 uses choke/cap coupling as do some of the 
early Silver Marshall and Pilot "transformers".  Dan
> 
> My basic question is why such larger audio chokes.  I note on the
> designs from the 20s and 30s it often calls for 30 H to 100 H audio
> chokes in the power supply line of the regen detector.   I can
> understand why one wants to decouple the audio and power supply but
> this seems out of line.   In modern day regen designs the choke often
> disappears and replaced by a hi value resistor.
> 
> In  addition some of the old articles talk about howl and some even
> suggest a hi value resistor in parallel with the choke to kill the
> howl.
> 
> Has anyone ever ran SPICE on the coupling circuits to see what the
> frequency response looked like with and without the choke ?
> 
> De stan ak0b
> 
> 
> 
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