UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - 6BE6/EK90 vs 6CS6/EH90 as frequency mixer in Trio 9R59DE ?

G8HQP Dave · 10th Nov 2019, 3:09 pm

The Pullen mixer is a strange circuit. Take an LTP (which in itself would make an awful mixer); degrade it by using a short tail; unbalance it by starving one side of supply rail voltage, hence introducing second-order distortion (which is exactly what a mixer needs). Yet it seems to work OK, and may be better than some valves designed to be mixers!

I have tried to understand Pullen's own explanation of how it works but he has such a strange way of understanding circuits and writing about them that I gave up.

10th Nov 2019, 3:09 pm	#26
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: 6BE6/EK90 vs 6CS6/EH90 as frequency mixer in Trio 9R59DE ? The Pullen mixer is a strange circuit. Take an LTP (which in itself would make an awful mixer); degrade it by using a short tail; unbalance it by starving one side of supply rail voltage, hence introducing second-order distortion (which is exactly what a mixer needs). Yet it seems to work OK, and may be better than some valves designed to be mixers! I have tried to understand Pullen's own explanation of how it works but he has such a strange way of understanding circuits and writing about them that I gave up.