Hi all! I've been scouring the internet for some time trying to figure this all out but I figured it might be better to speak to some actual humans that know what they're talking about. So I'm researching a new head and it says that the optimal load impedance is rated at 600 ohm. But I've never heard of it going over 8 ohm. Is 600 ohm the same as say, 6 ohm? Or is there any kind of conversion? I'm just trying to figure out what cabs I need to plug in to this. I'm not exactly up to speed on all of this yet, so sorry if this is a simple problem. I'd just like to be sure so I don't ruin anything!

That seems more like the spec for the DI out of the amp - the low impedance three-pin connector. Are you sure that is the optimal load impedence of the speaker output ?

On the technical specifications page it was the only thing related to ohms. But I could still always be wrong. It's a TC Electronic RH450 head if that helps with anything. Maybe someone knows about that one specifically?

600 ohm is standard XLR. Yeah, the TC Electronics RH450 spec page sucks. They say power out 450W (800W min load) but don't specify the minimum load If you follow the link and get the pdf, the minimum load is 2.66 ohms, kinda useless. So, for most useful applications, the minimum load is 4 ohms.

I wouldn't say that's kind of useless. A load of 2.66 ohms is a 4 ohm and an 8 ohm cabinet in parallel. That is asked about here all the time.

On the TC E website it lists different variations of cab sizes that you can plug into it. The one I was thinking about was the 4x10 and the 2x12. Are most cabs that are the same size the same ohm? Like, if I just choose a different brand of 4x10 and 2x12 than the ones TC E sells will it be the same?

If you are interested in the RH450, and TC line of cabs, I would recommend you go with two of the 212's and stack them vertically.

Yes. Doubling up on matching cabs is always going to be more of a good thing. Mixing cabs can be a crap shoot, and depending on a lot of factors not be a good pairing.

To answer this more general question, no. In fact some manufacturers will offer a given cab, usually 210s and 212s, in both 4 ohm and 8 ohm versions. So you really have to read the jack plate on the cabinet to see what its nominal impedance is (2, 4, 8, or 16 ohms, most common by far for bass are 4 and 8 ohm cabinets).