Impedance Question

[metalhead3ecr]

Is this right?

[fperron_kt88]

that's the idea, yes.

[metalhead3ecr]

awesome. Is that the best tonal option too?

[neikeel]

awesome. Is that the best tonal option too?

Ask a bit more and explain what you mean?

[metalhead3ecr]

Sorry for being so vague! What do you guys notice when changing the ohm rating on the amps and cabs? Are certain setup's stiffer than others? I hear Mesa saying things like more mids on one setup versus less on the other. What do you guys prefer? And also, if I want to select 16 Ohms, how would I need to hook up the two 8 ohm cabs i have? I think one has a series output. I don't really wanna rewire the speakers either.

[neikeel]

The important thing is, in general, keep the impedence matched bettween amp and cab. Yes you can mismatch when you are pulling tubes or using different tubes than those normally specced but for general use match.

So if using a single 16ohm cab use the 16ohm option, for two 16ohm cabs (which will become in parallel if you use normal Marshall jacks) use the 8ohm etc.

If you use higher rated cab than selected on the amp you can get unwanted flyback inside your OT and kill it. One step, lets say 8ohm amp into 16ohm cab for a hort while will be ok, but two steps 4ohm amp into 16ohm cab likely to be bad.

The other way, eg 16ohm aamp setting into 8ohm cab will let thee amp breathe a bit more and can give a more raw tone, again go two steps (16 into 4 and you risk trashing the output valves and more).

These points can also be affected if the NFB resistor is hooked up to the output jacks rather than a specific tap on the OT.

If you have two 8ohm cabs, and you want to use both and do not want to rewire, then the 4ohm selector on your amp is the only option.

Some people say that using the 16ohm tap gives better tone as you use all of the OT secondary windings, but I personally do not believe that

[metalhead3ecr]

Thanks! some great info right there