5D3 heaters

[Bugman3183]

Hello all, I was just looking st the schematic and layout for the tweed 5d3 and noticed half of the heaters were grounded.  This is something that I have never seen before and was hoping to get an explanation of why that is and if it is necessary to wire them that way as it would seem to me that it would have potential to induce hum.  Thanks.

[sluckey]

That's just the way they did it way back then. They used the chassis for one conductor, saving some wire and pennies. The less hummy Fender center tap heater circuit came about later on when the 6X series came out. Actually a few of the later 5X amps had the improved filament wiring.

[Bugman3183]

Cool.  Thanks for the info, wasn't sure if there was a specific purpose for that. I'm thinking about building one, never actually heard one but all the descriptions I've read makes it seem pretty interesting