100 watt impedance selector switch???

[-Ty-]

Hi, On my 100 watt build we have the purple wire that conects to the impedance selector switch and the turret board, attached to the green wire. But in our instructions it shows it on the yellow. What is the purpose of this wire and is it suppose to be with the yellow wire?

[paulster]

The wire between the impedance selector and the board is the negative feedback wire. Colour is not important but if it ends up at your presence pot via a resistor then it's the right one.

[flemingmras]

Hi, On my 100 watt build we have the purple wire that conects to the impedance selector switch and the turret board, attached to the green wire. But in our instructions it shows it on the yellow. What is the purpose of this wire and is it suppose to be with the yellow wire?

You can either connect it to the 8 ohm tap (yellow wire) like it was, or put it on any tap you want. I usually put them on the speaker jack itself. Not sure if there's any tonal differences or if the Presence affects a different frequency depending on which tap it's on.

[paulster]

I usually put them on the speaker jack itself. Not sure if there's any tonal differences or if the Presence affects a different frequency depending on which tap it's on.

If you put the NFB wire on the speaker jack, the amount of negative feedback will be altered depending on the cab you use.

For instance if you used a half-stack one day and then ran a full stack of identical speakers, the tone would change because the amount of negative feedback had been reduced as the impedance came down.

This doesn't happen when you wire it to the impedance selector and you pick the level of negative feedback you like by choosing the particular tap, and it'll stay like that regardless of the cab you use.