2 8ohm cabinets - how to wire down to 4ohms?

[Gord]

Hi guys,
Sorry if the title is misleading, I'm not even sure how to describe it. My orange amp has an ohm selector. I have two 8ohm cabinets. In the past, I've had amps that have one output that I bring to the first cabinet, then have a speaker cable going from that cabinets other jack to another cabinet.

With the orange, can I go
amp>cab>cab, and set it to 4 ohms?
or do I have to go
amp jack1>cab
amp jack 2>cab
?

[G RICH 5]

Providing both cabs are 8 ohms-either way is fine. Set the ohm switch, if there is one, to 4 ohms.

[BigOldHarry]

If you plug both cabs into your amp, it will create a 4-ohm load. If you amp has load selector, then you want to select it to 4ohms when using both cabs.

If you run your cabs daisychained (amp>cab>cab) I *think* it's the exact same load, but someone smarter than me (like Bill F) might want to chime in. I think it rather depends on how your cabs are wired, but most cabs with the "through" jack on them work the same way -

Remember, impedance is funny in that adding two together actually "halves" the impedance (which actually doubles the load, if you follow).

[Johnny Crab]

Scroll down a bit on this page:
Series Parallel Speaker Impedance

Also, read the Operating Manual for your amp as they should tell you.

The other things you can do:

Contact the manufacturer of the cabinets directly(email or phone, I do this all day with instrumentation stuff) to ask THEM how they are wired and how to connect the cabinets.

Get a cheap meter at Radio Shack(or Canada's equivalent) and measure the resistance across the tip & sleeve with the cabinets plugged in. It's NOT an impedance measurement but it will give you an idea(measure one cabinet, then measure with them hooked together, compare if the reading gets higher or lower).

[GrowlerBox]

Originally Posted by BigOldHarry

If you plug both cabs into your amp, it will create a 4-ohm load. If you amp has load selector, then you want to select it to 4ohms when using both cabs.

If you run your cabs daisychained (amp>cab>cab) I *think* it's the exact same load, but someone smarter than me (like Bill F) might want to chime in. I think it rather depends on how your cabs are wired, but most cabs with the "through" jack on them work the same way -

Remember, impedance is funny in that adding two together actually "halves" the impedance (which actually doubles the load, if you follow).

Both methods connect the cabs in parallel, resulting in a 4 ohm load (in this setting, these are essentially synonymous -- "load" would generally refer to resistance, so ignore Harry's last, rather confusing point).

[RickenBoogie]

Yes, either way you'll have a 4 ohm load, and either way is perfectly fine.

[okcrum]

Yeah, on the Orange the load selector basically sets the limiter threshold so that the power amp does not get overdriven.

[billfitzmaurice]

Originally Posted by Gord

can I go
amp>cab>cab...
or do I have to go
amp jack1>cab
amp jack 2>cab
?

The two are electrically identical.