Mk3 ohm issue..

I have a cab with two 8ohm speakers that each have their own separate cable so I can use one at a time or both. Mesa states if you have two 8 ohm speakers to plug 1 in the 4ohm and the second in the other 4ohm jack. I guess because it's wired in parallel? Anyway I noticed when I have just one 8ohm speaker in the 8ohm jack the amp it's louder and I get more high end. It sounds better. So I plugged one speaker in the 8ohm and the other in a 4ohm and it still sounds better (louder more highs) than the suggested "both 4ohm jacks". Im starting to think maybe the previous owner moded the amp to have the jacks in series instead of parallel? I could be wrong about it supposed to be parallel, this stuff confuses me and I'm not sure how mesa wires it from factory. So my questions are:

1: can I hurt the amp by having one 8ohm speaker in the 4ohm jack and the other in the 8ohm jack ?

2: is there a way I can tell if speaker jacks were moded from its normal parallel or series wiring?

It makes no sense that both 8ohm speakers in the suggested 4ohm jacks sound smoother with less highs. I know that's what happens when you plug a 8ohm speaker into a 4ohm load. But according to mesa the impedance should be correct by using the two 4ohm jacks. I'm I missing something here or?

HelpingFriendly said:

Im starting to think maybe the previous owner moded the amp to have the jacks in series instead of parallel? I could be wrong about it supposed to be parallel, this stuff confuses me and I'm not sure how mesa wires it from factory.

Click to expand...

The two jacks marked "4 ohms" should be wired in parallel. I can't imagine why someone would change them to series, but you can check by plugging one cab into a "4 ohm" jack and daisy chaining the second cab from the first cab's other input jack. If this sounds the same as plugging each cab into a "4 ohm" jack, then the outputs are parallel. If it sounds different, they might've been re-wired to series.

Maybe when you plug one cab into a "4 ohm" jack and one into the "8 ohm" one, the amp wants to see 8 ohms so your total impedance of ~4 ohms is mismatched...but that sounds better to you. Whereas when you only use the "4 ohm" jacks the amp is connected "correctly," but that doesn't sound as good to you. But I haven't played around with mismatching my Mark 3 like this, so I couldn't say how likely that is.

morgan138 said:

HelpingFriendly said:

Im starting to think maybe the previous owner moded the amp to have the jacks in series instead of parallel? I could be wrong about it supposed to be parallel, this stuff confuses me and I'm not sure how mesa wires it from factory.

Click to expand...

The two jacks marked "4 ohms" should be wired in parallel. I can't imagine why someone would change them to series, but you can check by plugging one cab into a "4 ohm" jack and daisy chaining the second cab from the first cab's other input jack. If this sounds the same as plugging each cab into a "4 ohm" jack, then the outputs are parallel. If it sounds different, they might've been re-wired to series.

Maybe when you plug one cab into a "4 ohm" jack and one into the "8 ohm" one, the amp wants to see 8 ohms so your total impedance of ~4 ohms is mismatched...but that sounds better to you. Whereas when you only use the "4 ohm" jacks the amp is connected "correctly," but that doesn't sound as good to you. But I haven't played around with mismatching my Mark 3 like this, so I couldn't say how likely that is.

Click to expand...

Thanks for the reply. I'm gona check tonight and see what the wiring looks like on the jacks. I just don't see how I get more clarity and output when mismatched. It should sound softer?

Here is some pics. 8ohm is the far right. The black stuff on the Yellow wire is just liquid electrical tape FYI

The two on the right look parallel to me. But I guess more importantly, it doesn't look like the wiring's been changed.