Sunn 100s Impedance switch

[shibbz]

My Sunn 100s' output is wired as 16 or 8 ohms. (1x16, 1x8, 2x8 routing to the 4 ohm tap)
I'd like to make it where I can run one 4 ohm cabinet or one 8 ohm cabinet or two 8 ohm cabinets at 4 ohms.
I think I understand how, but what happens to the 16 ohm tap? If I put the yellow(16ohm) wire where the brown(4ohm) wire is in the picture, does that mean that when both jacks are used that it will switch to the 16 tap, sort of like running in a series? Also, when changing wires, does that thinner yellow wire stay where it is?
(note this picture is before any modification.)

[loudthud]

Study the last pic posted in this thread: http://sunnforum.ampage.org/sdp/index.php/topic,4844.0.html

The 16 ohm tap is connected to the terminal strip where the skinny yellow wire goes now. That's for the feedback to the 6AN8. The brown wire will have to be disconnected from the terminal strip and connected to the extention jack.

Edit: fixed link

[shibbz]

Awesome thanks so much!
So the thin yellow wire should be removed?
And when I plug in 2 8 ohm cabinets, will it run at 4 or 16 ohms?

[loudthud]

Unsolder the orange wire at the Extention jack and solder the brown wire to that terminal.

Unsolder the yellow wires from the Extention jack and connect the brown wire to that terminal.

Unsolder the skinny yellow wire from the terminal strip and connect the yellow wire from the transformer to that terminal.

[shibbz]

Would this be the proper way to wire a 3 way impedance switch? What would I do with that thinner yellow wire if I were to wire it this way?
Here's the switch I had in mind. http://store.triodestore.com/1pol3pos.html

[WWWizard]

Did the impedance change with the 1968 model w/ Reverb?

I have a 1967 (No Reverb) -- just had it looked at by a tech and after checking out the schematic he told me it was 8 Ohm and 4 Ohm outputs.

It appears that the output sections of both schematics are the same..

Can anyone confirm? That based on both models, the Speaker out is 16 Ohm and the Ext. Speaker is 8 Ohm.

Here are the links:

http://sunn.ampage.org/site/schematics/100snorev.jpg *No Reverb
http://sunn.ampage.org/site/schematics/100s.jpg

[EdBass]

All of the Sunns from that era had 16, 8 and 4 ohm taps from the OT as you can see by the schematics you attached. However they were wired two different ways from the factory; some 8 and 4, some 16 and 8.
This thread is addressing how to switch the outputs from the 16 and 8 ohm output wiring it left the factory with to the 8 and 4 ohm wiring scheme in order to work better for shibbz's application.

This has been addressed frequently before. If you search "impedance" and do a little digging you will find lots of info about the early Sunn output wiring nuances.

Welcome to the Forum!

[WWWizard]

Thanks Ed.

Did some researching on the forums and found the needed info. Seems as though mine is running the 1968 factory 8, 4.
Time to switch it up to a 16, 8 so I can put it through my orange 412.

[shibbz]

Could someone draw me a diagram of a re-wired output, including that thin yellow wire?
That's the only one confusing me.

[loudthud]

Follow the link in my first reply in this thread. If your amp is wired for 16/8 ohms it will look like the first picture. You need to make it look like the third picture. Follow these instructions:

Unsolder the orange wire at the Extention jack and solder the brown wire to that terminal.

Unsolder the yellow wires from the Extention jack and connect the brown wire to that terminal.

Unsolder the skinny yellow wire from the terminal strip and connect the yellow wire from the transformer to that terminal.

The only step I left out is that you dispose of the yellow wire in accordance with local regulations. You don't need it, throw it away.

[shibbz]

Awesome, thanks!
What does that mean, it being the feedback 6anb? Sure it isn't necessary?

edit:
I just called my tech and he said to leave the 6anb where it is and just move the output around needed.
He said if I removed it I'd lose headroom?