[Milsurplus] BC-474 modulation increase

[David Stinson]

Hue Miller wrote:

> At the SEA-PAC hamfest at Seaside OR ( nice town, i think, good scenery and layout,
> wouldn't mind if i had found a job there instead of further down the coast ) Blair Shaw
> told me about the WW2 US Army set BC-474, that he had substituted a 6L6 tube for
> the 6V6 modulator and achieved a higher modulation percentage. At first i was aghast
> thinking the extra current load might burn out a modulation transformer, but he says no,
> it works fine. Anyone else verify this is worthwhile, or tried it?

I found a 6L6 plugged into one of mine.
I replaced it at once.  Maybe it will damage the circuit
and maybe it won't, but a small gain in modulation
doesn't justify risking an irreplaceable part.
I have no trouble getting acceptable modulation from mine
with a telephone carbon mike element.  I've worked several
stations on AM phone with it.
73 Dave S.