Tube Amp Archive

Hi, for this sort of arrangement, with an OT on the speaker directly, can I simply run wires from the tabs on the speaker to a jack (mounted on a rear panel) and use that for a larger speaker of the same impedance.

If you run a second speaker in parallel, you will be lowering the impedance seen by the OT. You could simply disconnect the OT secondary wires from the existing speaker and connect them to a jack. Then plug whatever speaker you want into the jack.

Ok sure, maybe set up an external jack from the OT and put a male jack on the speaker tabs,

Thanks

Yeah, LOL, I think we call that thing a plug. Right idea, hard wire the plug to the speaker, or use spade lugs that fit tightly. Just take care that they don't slip off the speaker tabs or you'll be running with no load.

I would use a switching jack and wire it such that with nothing plugged in the OT will be connected to the internal speaker. But as soon as you insert a plug the internal speaker is disconnected and whatever speaker is on the other end of that plug/cable will be connected to the OT.

Steve, might you supply a quick schematic? This is for a speaker mounted transformer.

Makes no difference where the OT is physically mounted...

Re-working

no

This? Corrected for the 12A tabs

Do you find your drawing easier to understand than my drawing?

Have you installed the iso transformer?

Your schematic is quite clear, just trying to translate to a layout.... not good? Iso Transformer is on the way.

I am looking to confirm the impedance of this speaker and when I read the terminals I consistently get .5 ohms? Schematic calls for 8 ohm so I should be seeing about 6ohms on the meter. With the transformer mounted on the speaker, is that affecting my reading?

Definitely.

OT secondary is a short length of thick wire.