Stupid Ohm Question

[JackBileDuct]

Sorry for the dumb question but here goes...

Currently have a Blackstar HT5 and two Bogner 2x12 cabinets that are 8 Ohm each. I've read that when you are running to cabinets you divide the Ohm's in half. I'd thought that was for daisy chain but I'm not certain. There is no 4 Ohm output on the Blackstar so I'm wondering if I'm going to toast it by running 2 8 Ohm cabinets.

Have a buddy with a Tweaker 15 and I was pretty impressed and about to order one but am curious if it will run two 8 Ohm cabinets and if so what do I set the amp at? The cabinets only have a single input so I wouldn't be chaining them together but using the two outputs on the amp.

Thanks in advance for any help.

[Tele Wacker]

If your amp head has 2 speaker inputs/outputs, you should be fine if each of your cabinets is 8 ohms. You should have total of 4 ohms using 2 cabinets. Plug one cab into one speaker output and the other speaker cab into the other speaker output.
I'm a Fender guy but this rule should work with other brands.

[freaksho]

yeah see what the back of the amp says, or the owner manual. but most likely it's designed to do what Tele Wacker said.

[JackBileDuct]

Thanks. My BlackStar doesn't even mention 2 x 8 ohm but it does have an 8 ohm jack. The pair are labeled 1 @ 8 ohm ( under the first jack ) and 2 @ 16 ( under the second ). So I guess when I run two 8 ohm cabinets I'm really running 4 Ohm and the amp is expecting 16. Since it doesn't have a 4 Ohm jack or switch, I guess I'm screwing it up by doing that.

I see the Tweaker actually has a switch so if using both output jacks on the amp and two 8 ohm cabinets I guess I'd set the switch to 4 Ohms. Didn't really need much of a reason to pull the trigger on it but I think that is enough to push me over the edge.

[SteveO]

It sounds like the amp wants an eight ohm load total. 1x8ohm=8ohms, and 2x16ohm (in parallel)=8 ohms. Some amps can handle a mismatch, some can't.

[Rockyrollercat]

Your amp needs to see an 8 ohm load (2@16 equals 8 ohms). If you hook two 8 ohm cabs to it, it will see a 4 ohm load and cook itself. Never under load your amp, it lets the electric shoot through too fast which makes the heat that fries it.

[JackBileDuct]

Thank you guys. I'd ran the two cabinets together maybe for an hour tops. Amp seems to be just fine but I unplugged the second cabinet after my post above.

After playing my friend's Tweaker, my Blackstar just sounds like cheese to me anyway so next time MF runs a 15% off deal I'm going to get the Tweaker and ditch the Blackstar. It has two outputs and a 16, 8, 4 switch so will have no issues running two 8 Ohm cabinets.