1967 Sunn 200S help!

[from_the_hallows]

Hello, all!

I just purchased a 1967 Sunn 200s bass head and I am running it through an 8ohm cabinet.

On the back of the head there are two speaker inputs, one labeling "Speaker" and one "External Speaker".

I am unsure of which input is 4ohms and 8ohms. I have attached a schematic for the head from 1967, I do not know how to tell which speaker input corresponds to which ohm load.

I would appreciate any help.

[loudthud]

You can never be sure that your amp hasn't been modified or that it matches the schematic exactly. This question is ask quite often here. This is the best thread on the subject: http://sunn.ampage.org/sdp/index.php/topic,4844.msg18880.html#msg18880

[alotawatts]

Far right is 4ohm usually

[EdBass]

Far right is 4ohm usually

Unless it's factory wired for, or been rewired for 16 and 8 ohms. I think it's a good idea to take a peek at the jack wiring; particularly when the outputs aren't labeled.

[from_the_hallows]

Thanks for all the help everyone, I was able to check the wiring and found that the far right input is 4 ohms for external speaker and speaker input is 8 ohms.

Now, I may doom happily through my ATLAS custom 2x15 cab.   

[pickinatit]

You maybe already know this,  but just in case.....

(veterans correct me if I'm wrong)

You can plug a single 8 ohm cab into the 8 ohm jack
OR  you can plug a single 4 ohm cab into the 4 ohm jack
OR  you can plug an 8 ohm cab into each of the two jacks (creating a 4 ohm load) and the outputs will automatically be  "switched"  to the 4 ohm tap.

[from_the_hallows]

I have never used both input jacks, although I have daisy-chained two 8-ohm cabs into the 4 ohm load which works.

I believe what you are suggesting works as well. Maybe someone can confirm this.

[Isaac]

You maybe already know this,  but just in case.....

(veterans correct me if I'm wrong)

You can plug a single 8 ohm cab into the 8 ohm jack
OR  you can plug a single 4 ohm cab into the 4 ohm jack
OR  you can plug an 8 ohm cab into each of the two jacks (creating a 4 ohm load) and the outputs will automatically be  "switched"  to the 4 ohm tap.

This is correct, if the head is wired for 8/4 output.