1969 Twin Reverb extension speaker jack

[Reeek]

I have never really understood what the real impedance should be when I use an extension speaker with my Twin Reverb. Should the extension cab be 4 Ohm too?

Thanks

[Old Tele man]

yes.

[Blue Strat]

I have never really understood what the real impedance should be when I use an extension speaker with my Twin Reverb. Should the extension cab be 4 Ohm too?

Thanks

The combined impedance that the amp "wants" to see is 4 ohms regardless of how many jacks you use and how many speakers.

Fenders are ok with a 1:2 or 2:1 mismatch, but you lose some power with an impedance mismatch.

[Reeek]

Thanks, guys. I have a new JDesign cab loaded with a Weber 12A125 and a 12F125 for a 4 Ohm impedance so this should be fun today :D