100 ohm resistors in 5e3

[bnew63]

just finishing up a mission tweedy build.
Wanted to make sure I'm on the right track
Are the 100 ohm resistors on the 6v6 pin 2 & 6 there to simulate a centre tap?
The Pt I'm using has a CT already.Do I just eliminate the resistors.

Brian

[John]

It should be pins 2 & 7 for the filaments. 6 has no connection. But yes they are for the artificial CT for the filaments.

Use either the CT off the tranny or the 100r resistors, but not both.

Also, if your 6v6 are cathode biased, you can ground your CT (artificial or otherwise) to the cathode pin of the 6v6 socket. That "elevates" the heaters, and some find it helps to minimize heater hum.

If someone says I'm wrong about all this, they're right.  But if you're using the 5e3 schem I've seen, I should be okay. Hope this helps!

[TubeGeek]

If you already have a filament centre tap, use it and don't worry about using the 100 ohm artificial centre tap resistors.

[HotBluePlates]

And the only time I can recall seeing the 100 ohm resistors mounted on the 6V6 socket, they were used to connect the midpoint of the resistors to the 6V6 cathode (pin 8) to provide an elevated dc heater reference, as well as an artificial center-tap.

You shouldn't have to do that though. If you have a filament center-tap, use it. I didn't in my 5E3 build; I also forgot to install those resistors until the build was done and powered up. The only neat place left to mount them was from the heater pins of V1. I connected the ground ends of those resistors together with a ring terminal, and secured that terminal under the nut holding V1's socket mounting screw. That amp has no hum.

The point there is that the resistors can be placed anywhere along the heater string.

[bnew63]

Thanks for the quick replies
I'm assuming the wires from the 22uf cap to pin 2 & 7 still need to be installed

Brian

[TubeGeek]

Thanks for the quick replies
I'm assuming the wires from the 22uf cap to pin 2 & 7 still need to be installed

Brian

No, they don't need to be connected if you are going to use the heater centre tap.  Those 100 ohm resistors connect to the + of the cap which is also the cathode connection.  As per the layout the heaters will have an elevated voltage in order to reduce hum.

Simply omit the resistors and the connection from pins 2 and 7 to the 22uF cap.  

hope this helps.