Question regarding ohms and my 200s

[spawnofthesith]

Hi, as of today I am the proud new owner of a 1967 200s. Now, my question is, what is the ohm rating of this amp? I have been trying to find some information about ohmage, but I have not had much luck. I have been running it with my 8 ohm mesa 4x12, but I wanted to make sure that was a safe match up, as I don't want to damage the amp, and I am a noob when it comes to the whole ohm thing.

Thanks!
~Tom

[EdBass]

Sunn amps from that era have output jacks wired either for 8 and 4 ohm, or 16 and 8 ohms, and default in parallel to the lower of the two impedance's when both are used.
The output transformers all have taps for 4, 8, and 16 ohms; it depends on how it was wired from the factory. If your jacks aren't labeled, you'll need to open it up and see what color wires are actually attached to the jacks, but the good news is that either output wiring will have an 8 ohm jack for your single Mesa cab.

Congrats on your score!

[spawnofthesith]

Thanks for the info! I am glad to hear that I am ok either way with the 8 ohms. For future reference though, what is the color match up for the different ohms?

Also, an unrelated question, but what does the polarity switch on the front do?

[EdBass]

You are OK; provided of course you are using the correct jack of the two on the back of the amp. They are wired kinda different from most amps with impedance selector switches.

This thread should answer your questions about output jack wiring;

http://sunn.ampage.org/sdp/index.php/topic,4844.0.html

The polarity switch switches the polarity of the AC into the amp.
If your amp is stock it has a 2 prong AC plug; the polarity switch has the same effect as unplugging the amp and inverting the plug, but without unplugging the amp.
In the olden days, most wall sockets were ungrounded so consequently most devices had 2 prong ungrounded plugs. Often it was necessary to adjust your polarity one way or the other to help combat unwanted noise, or more importantly to avoid getting "zapped" and leaving part of your lip on a microphone.
You might want to look into getting that 2 prong ungrounded situation remedied....

Also, if your amp is stock and has been sitting as is often the case with these old beasts, you may want to have a tech "freshen it up" a little to get the best performance out of the old girl.

If you use the search function here you will find lots of recommended updates for old Sunns.

[spawnofthesith]

Thanks, looks like my amp is wired for 8 and 4 ohms, so I've had it all properly connected *sigh of relief*. Chords been changed to a 3 prong one, so I am good there. The guy I bought it from was using it, but I sent him an email asking him if the caps had ever been replaced by him or by a past owner to his knowledge. Per his response I will take it to a tech for some brushing up accordingly. Thanks again!