Re: When to fit valve screening cans?
>What are the valves doing?
I have 4 valves as a superhet: E88CC double triode 3.5MHz/455KHz mixer, E88CC double triode 455KHz product detector, 12AX7 two stage AF amplifier, and 12AT7 oscillators near 4MHz and 455KHz.
It's all narrow band with trimmers to absorb circuit strays. At these frequencies small changes in anode/earth capacitance may not be significant but I do take your point.
All in all it looks like it's better to use screening cans as the default.
73, Alan G3XAQ
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