Impedance on the Mesa Road King 2x12 Combo

[24fretter]

After reading your posts, I decided to join the forum. I have a Blackstar HT-1R combo coming in preety soon. It has an 8 ohm out in the back panel. Ialso have a Road King I 2x12 combo. At the back, the speakers are connected to an output the says 8-16 Ohms(combo) would I be able to plug those speakers to the blackstar combo with an 8 ohm output? Thanks so much.

[Caevan O'Shite]

Welcome to the GPF, 24fretter!

 

OK; does your Road King have a pair of 12" Celestion C 90 speakers in it? They are probably 8 ohms each, am I right?

 

 

If they ARE 8 ohm speakers (most common in a 2x12):

 

-If they are wired together in parallel, their combined total impedance will be 4 ohms, and should be connected to a 4 ohm output. In this case, it would NOT be a good idea to connect them to an 8 ohm output- it's safe to run a tube-amp into a higher impedance than called for, BUT NOT A LOWER ONE.

 

-If they are wired together in series, their combined total impedance will be 16 ohms, and should be connected to a 16 ohm output. They would also be OK if connected to an 8 ohm output- it's safe to run a tube-amp into a higher impedance than called for, BUT NOT A LOWER ONE.

 

 

IF they are 16 ohms apiece (not as commonly seen in a 2x12 combo, but possible):

 

-If they are wired together in parallel (which would be most likely if they are 16 ohm speakers), their combined total impedance will be 8 ohms, and should be connected to an 8 ohm output. In this case, it would be a perfectly fine idea to connect them to an 8 ohm output.

 

It is not very likely that two 16 ohm speakers would be wired together in series, as the resulting combined total impedance would be 32 ohms- which is an extremely unlikely impedance to be chosen by a guitar amplifier designer or manufacturer.

 

Note: if you need to contact MESA/Boogie's tech Support:

 

Please direct product inquiries and Tech support questions to the factory in Petaluma :

 

US Domestic Support: (707) 778-6565