Safe OHM mis-match?

[napalmdeath]

I'm running my EVH 50 into the matching 2x12, (16 ohms), and an additional Mesa 1x12 Thiele, (8 ohms). I have the amp set to 8 ohms.. It sounds outstanding! the focus shifts to the Thiele, and lightens the bright character of the EVH cab, (brand new, speakers need broken in). Many have said it's safe, including Fender tech support. Just wanted more assurance, I guess. I know 4 ohm setting would be absolutely ideal, but loses focus, sounds muddy.

 

[Nico]

That is not safe in theory. You should be running 4 Ohms.

The way its ok to mismatch is if your cab is 16 ohm and the amplifier is set to 8 ohms
Or an 8 ohm cab into a 4 ohm set on the amp.

 

[BackCrack]

16 ohms in parallel with 8 ohms = 5.33 ohms, with the majority of the power going to the 8 ohm cab.

 

[blackba]

It's a mismatched either way you do it. If the 8 ohm tap sounds best use that. It does stress the amp some, but you should be fine.

 

[GuitarGuyLP]

Using a lower impedance load is bad for a solid state amp, but that does not really apply for a tube amp. The output impedance is matched to give a proper frequency response. A mismatch changes that response and results in a brighter, or darker sound with less power available. It is not like a solid state amp where the output sounds the same, but with a lower impedance it puts more stress on the output transistors, and also puts out more power with a lower impedance load.