08-18-2015, 03:35 AM
In my schematics from the Philco 1941 Yearbook, part 57 in the 41-280/285 is a .002 uF condenser between the plates of the two 41 tubes, which is a different way of saying between the white and black wires from the output transformer. Part 68 is a 33 ohm resistor in series with the dial light used only in the 41-287, so ignore it.
In the 41-250/255 schematic, parts 57 and 68 are .003 uF condensers from the plates of each of the 41 tubes to ground.
It's only a guess, but since the 280/285s are consoles with larger speakers, the difference might be to adjust the tone for use with the tabletop and console speakers, maybe to give the larger speaker a brighter sound or reduce boominess. Conversely, maybe they wanted to add bass to the smaller table top speakers.
If it wuz me, I'd leave the 41-285 chassis stock and not modify it to agree with the 41-255 schematic. I used a 41-250 chassis in my 41-280 cabinet for a few weeks while I was recapping my 41-280 chassis without noticing any difference in the tone. Of course, if I understand it right, you're going the other way: using the console chassis in the tabletop cabinet. Still, I think I'd leave it original. If you don't like the tone and can't adjust it to your liking with the bass control, it should be simple to make the change.
One could argue the other way, I suppose, to make the change now and unmake it if the tone isn't satisfactory. After all, you're mixing and matching the chassis and cabinet anyway. Since your chassis is stamped 41-285 I think I'd make a little effort to keep it all 41-285. But I'm only a little bit of a purist. I'd never say leave it original even if it sounds bad. And it's your radio any way you play it.
In the 41-250/255 schematic, parts 57 and 68 are .003 uF condensers from the plates of each of the 41 tubes to ground.
It's only a guess, but since the 280/285s are consoles with larger speakers, the difference might be to adjust the tone for use with the tabletop and console speakers, maybe to give the larger speaker a brighter sound or reduce boominess. Conversely, maybe they wanted to add bass to the smaller table top speakers.
If it wuz me, I'd leave the 41-285 chassis stock and not modify it to agree with the 41-255 schematic. I used a 41-250 chassis in my 41-280 cabinet for a few weeks while I was recapping my 41-280 chassis without noticing any difference in the tone. Of course, if I understand it right, you're going the other way: using the console chassis in the tabletop cabinet. Still, I think I'd leave it original. If you don't like the tone and can't adjust it to your liking with the bass control, it should be simple to make the change.
One could argue the other way, I suppose, to make the change now and unmake it if the tone isn't satisfactory. After all, you're mixing and matching the chassis and cabinet anyway. Since your chassis is stamped 41-285 I think I'd make a little effort to keep it all 41-285. But I'm only a little bit of a purist. I'd never say leave it original even if it sounds bad. And it's your radio any way you play it.
John Honeycutt
