IMPEDANCE Rec for vintage BFDR Extension CAB???

[lakehaus]

I am building an extension cabinet for my 65 Deluxe Reverb amp combo. The speaker loaded in the combo is 8 ohms. There is a 1/4" out for an extension cabinet. I'm not sure, and I haven't been successful in finding, the recommended impedance for the external speaker.

Any techies know the answer? This is not a reissue combo.

Thanks!

[img:640:480]http://i256.photobucket.com/albums/hh17 ... G_0529.jpg[/img]

[Structo]

The ext jack is wired in parallel to the built in speaker.

The cab speaker jack is a switched jack.

If you run both the 8 ohm cab speaker then add a 8 ohm speaker the load will be 4 ohms.
Does your amp have an impedance selector switch? I don't think it does.

The other thing you could do is make a 2x12 with two 16 ohm speakers in parallel and plug that into the main jack and not run the combo speaker.


Are you wanting to run both the combo speaker and the ext cab?

[Bob Simpson]

supposedly very tolerant of a 100% mismatch.

I think you'll be ok with an extension speaker at 8 ohms
in parallel with the 8 ohm speaker in the DlxReverb, showing
4 ohms to the OT secondary.

That's why they put the extension speaker jack there...

Good luck! Nice '65...

Bob Simpson

[lakehaus]

The ext jack is wired in parallel to the built in speaker.

The cab speaker jack is a switched jack. I don't know what that means...

If you run both the 8 ohm cab speaker then add a 8 ohm speaker the load will be 4 ohms.
Does your amp have an impedance selector switch? I don't think it does. I don't know, but you're probably right...

The other thing you could do is make a 2x12 with two 16 ohm speakers in parallel and plug that into the main jack and not run the combo speaker. Good idea, but I already have the framework and material for a 1x12...


Are you wanting to run both the combo speaker and the ext cab? Yes, I want to use the combo's speaker while the ext. cab is running...

See my responses above in bold italics.

[lakehaus]

supposedly very tolerant of a 100% mismatch.

I think you'll be ok with an extension speaker at 8 ohms
in parallel with the 8 ohm speaker in the DlxReverb, showing
4 ohms to the OT secondary.

That's why they put the extension speaker jack there... So, it's designed for an 8 ohm load?
Good luck! Nice '65... Thanks, it's a sweet running amp.

Bob Simpson

See my comments above in bold italics

[jjman]

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Caught Spinal Tap last night on TV again. "Big Bottom"