I wonder why it was that some (many?) designers in the 40s and 50s put the on/off switch on the tone pot instead of the volume pot, when the volume pot is such a logical place to put it?

Maybe so you could leave the radio at your preferred volume?

Perhaps that was the thinking, but I expect that most people set volume for the circumstances and set and forget tone once.

I seem to remember reading that the reason for this was to avoid possible hum pickup. A lot of Tone controls are in the plate circuit or the bias feed to the output valve. Volume controls are usually in the grid circuit of the voltage amplifier &, therefore, more susceptible to hum pickup. Having said that, I have worked on both & cannot hear much difference.
John.

I thought this was more common on four valve AWA mantel sets than other brands. EG: the bakelite Radiola Champion model 429MA of 1950 and the subsequent 449MA in a coloured thermoplastic cabinet.

By the late 1940's most manufacturers were ditching tone controls on mantel sets to keep prices down.

6A8G: I seem to remember reading that the reason for this was to avoid possible hum pickup.

I'm looking for a deliberate design reason and that one seems logical.

Brad: I thought this was more common on four valve AWA mantel sets than other brands.

Possibly. Two of my four radios have the power switch on tone: the Airzone and the Hotpoint (which has an AWA chassis).

One thing I liked about it was that the volume level never had to be altered and because I like plenty of bass in music I never had to turn the control far after hearing the click of the power switch.

I am not sure what motivated the manufacturers though.

I have a Weldon console from 1934 and it has a seperate power switch (a seldom included feature in that decade) and I would have to say that is the most preferable configuration - each control doing its own thing.

In the USA, with our hot chassis "All American 5ive" radios, the volume control always had the power switch, and the switched side of the line was the chassis ground line. So the power wires nearby the volume control and switch were essentially at 0V potential. So no hum pickup. And wheh the radio is switched off, of course it's quiet!

I like what Healing did on my radio of theirs; they had a pair of concentric controls, volume and tone on the left, and tuning and power on the right.

My Astor Has the on/ off Control as a separate switch, I prefer this set up , as you can leave the volume & Tone on the Desired Adjustment, Kriesler also has the on/off Tone set up also, with the 11-81 Model