UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Interesting Armstrong AM detector circuit.

Argus25 · 29th Oct 2017, 11:00 pm

Colin,

For the most part I have found that the standard text books cover topics pretty well and I have a good collection of books from the UK & USA. However over the years I came across really only three topics that were not covered to my satisfaction;

1) Time constants of AM detectors
2) Energy recovery or efficiency diode circuits for TV
3) THe frequency response of interstage audio transformers in vintage valve radios.

So I did at one point an article on each of these topics, if for nothing more than to help myself understand them better.

If you look on the website you will see an article on the Evolution of the Damper Diode, it explains how we ended up with the common configuration line output transformer design, which is certainly not an obvious thing , the steps to get there.

The transformer analysis and the equation for the audio interstage transformer frequency response is hiding inside the article on the Grebe MU-1 radio, this equation is not available eslewhere because generally the modelling is not done for a transformer with an unloaded secondary.

Hugo.

29th Oct 2017, 11:00 pm	#19
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Interesting Armstrong AM detector circuit. Colin, For the most part I have found that the standard text books cover topics pretty well and I have a good collection of books from the UK & USA. However over the years I came across really only three topics that were not covered to my satisfaction; 1) Time constants of AM detectors 2) Energy recovery or efficiency diode circuits for TV 3) THe frequency response of interstage audio transformers in vintage valve radios. So I did at one point an article on each of these topics, if for nothing more than to help myself understand them better. If you look on the website you will see an article on the Evolution of the Damper Diode, it explains how we ended up with the common configuration line output transformer design, which is certainly not an obvious thing , the steps to get there. The transformer analysis and the equation for the audio interstage transformer frequency response is hiding inside the article on the Grebe MU-1 radio, this equation is not available eslewhere because generally the modelling is not done for a transformer with an unloaded secondary. Hugo.