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turretslug · 2nd Mar 2016, 9:47 pm

Are these the string of resistors associated with the oscillator HT feed? I suspect that these end up at the second grid from the cathode of V1, via the feedback winding?- if so, this grid acts as the anode of the oscillator circuit, a sub-anode if you like, and the valve's combining of this oscillatory electron stream with that produced by the aerial signal at the signal grid results in the mixing action with the intermediate frequency component appearing at the main anode (that's an enormous over-simplification, by the way, this is a subject where some (not me!) could fill many pages with explanation). This is what's referred to as multi-grid mixing, sometimes this circuit is known as a "converter" as both oscillating and mixing are done by one valve and electrode structure.

Yep, crossed!

2nd Mar 2016, 9:47 pm	#90
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,397	Re: HMV 653 Broadcaster all wave. Are these the string of resistors associated with the oscillator HT feed? I suspect that these end up at the second grid from the cathode of V1, via the feedback winding?- if so, this grid acts as the anode of the oscillator circuit, a sub-anode if you like, and the valve's combining of this oscillatory electron stream with that produced by the aerial signal at the signal grid results in the mixing action with the intermediate frequency component appearing at the main anode (that's an enormous over-simplification, by the way, this is a subject where some (not me!) could fill many pages with explanation). This is what's referred to as multi-grid mixing, sometimes this circuit is known as a "converter" as both oscillating and mixing are done by one valve and electrode structure. Yep, crossed!