100S Question- @ speaker outputs in back??

[jerryjg]

 
Hiya. There are two speaker outputs in back of My Sunn 100S One is for the main 8 ohm load, and the other is for an 4 ohm external speaker. How exactly does this work?
Do I need to have an 8 ohm speaker or cabinet plugged  into the 8 ohm Input at all times, or can i just use the one external input with a 4 ohm speaker or cabinet  and not plug anything into  the main 8 ohm input?
Thanks you.

[HRobert]

When using one 8 Ohm cabinet, you would use the "8 Ohm" out.  When using 2 - 8 Ohm cabs, you obvisouly would use both. the power transformer then recognizes the total load of 4 Ohms.  If you have a 4 Ohm cab..you would use just the 4 Ohm out.

[eardrum]

When using one 8 Ohm cabinet, you would use the "8 Ohm" out.  When using 2 - 8 Ohm cabs, you obvisouly would use both. the power transformer then recognizes the total load of 4 Ohms.  If you have a 4 Ohm cab..you would use just the 4 Ohm out.

Rats. Is this true? I've wired two paired speaker cabinets (and used the rig for years with no problems) which collectively incorporate two JBL D-140s and four 12" Norelcos (from a Traynor YR-412) to have two inputs: one 8 Ohm and one 4 Ohm. I did this specifically to take advantage of the two outputs from my Sunn 200S. How much damage am I doing to the amp by plugging an 8-Ohm load into the 8 Ohm output jack and a 4-Ohm load into the 4 Ohm output jack (instead of two 8-Ohm loads)?
(I apologize if this is an old topic in this forum. I just joined because I'm going to sell my gear and want to be up to speed in case a buyer has questions. Thanks.)

[biltmore]

Is this true?

Yes, it's 100% true.

[Isaac]

Total impedance is about 2.3 ohms. Probably won't cause any damage, but it isn't the ideal load for the amp.

[loudthud]

Those Norelco speakers are usually blown when you find them. They can't take much power.

A lot depends on how loud you play. If you use primarily clean sounds, I wouldn't expect any problems. If you play with all controls on 10, an overdrive pedal, and a guitar turned down to C, I be surprised if the amp didn't self distruct after a couple of gigs.

[Isaac]

Could be. The impression I've got over the years - and I stress that it's only an impression, not based on solid personal research - is that tube amps are pretty tolerant of mismatches up to 100% (or +100%, -50%, if you prefer). I usually play bass, and even when playing guitar, rarely if ever go balls to the walls all the time, and I have never had any trouble. This might not be the case for someone playing closer to all distortion, all the time.