Tweed Champ output transformer help

[Rigid Digit]

I have a Tweed Champ clone, the output transformer has three taps for 4,16 and 8 ohm output. Currently its wired for 4 ohm. I want to run into an 8ohm 10" speaker. How do I work out which wire to use?

Many thanks people.

[Jaybird]

There should be a wiring diagram for the transformer that will tell you. 8 ohm is usually green, but you will have to check. Who is the maker of your OT?

[mojo2001]

Measure the resistance of the secondary windings with a meter.

The low resistance winding is 4 ohm, the high one is 16, and the one in the middle is 8.

[e-merlin]

Originally Posted by Jaybird

There should be a wiring diagram for the transformer that will tell you. 8 ohm is usually green, but you will have to check. Who is the maker of your OT?

+1. I need something like that for my build.

[JohnnyCrash]

A manufacturer/brand and model/part number will help.

[Rigid Digit]

I don't have a wiring diagram for the OT. Its a Mojo transformer.

I'm not the best with these things, how to I measure it with a multimeter please?

[Jaybird]

I think you may have a Mojo Tweed Deluxe Transformer if it has 3 taps. The # would most likely be 768 HTS-9305 9960813. There would be an orange-4ohm, yellow-16ohm, and green-8 ohm tap. I would suggest you ask the people at Mojo. They will most likely be willing and happy to let you know. Good Luck.

[mojo2001]

Mojo can tell you the color code but to measure with a meter:

Set meter to Resistance/Ohms (low scale)

Measure the resistance between the ground wire (usually black) and each secondary wire...should come out something like 0.4, 0.7. and 1 ohm for 4 ohm, 8 ohm, and 16 ohm tap respectively.

Actual resistance may be different from what I quoted, but the notion that higher ohm taps have more wire between ground and the tap, hence more resistance(ohms), is what is important.

[Jaybird]

Originally Posted by mojo2001

Mojo can tell you the color code but to measure with a meter:

Set meter to Resistance/Ohms (low scale)

Measure the resistance between the ground wire (usually black) and each secondary wire...should come out something like 0.4, 0.7. and 1 ohm for 4 ohm, 8 ohm, and 16 ohm tap respectively.

Actual resistance may be different from what I quoted, but the notion that higher ohm taps have more wire between ground and the tap, hence more resistance(ohms), is what is important.

Thanks for that information Mojo2001, Cool stuff if there is no company info.

[JohnnyCrash]

I doubt it's a Deluxe OT. A Champ is single ended and a Deluxe is P-P, so there'd be one more primary wires (unless there is something not mentioned).

Black = Ground.
Red = 6V6 plate.

After that, eMail Mojo. Companies usually keep the same color scheme forever :)

[Rigid Digit]

Thanks for your help everyone.