#1
I have to admit, as long as I've played guitar the only thing I've known about ohms is that you match the head to the cab (ex. 8 ohm head = 8 ohm cab). My question is, the head I'm using now has a 4,8,16 ohm switch, and the cab I'm using has a 4,8,16 ohm switch as well. So basically, I can use 4, 8 or 16 ohms, so what's the difference, if any at all? Thanks.
#2
What kind of cab? I've never heard of one having a 4,8,16 switch... Isn't that impossible?

Unless its like a Marshall 1960 where it is 4 or 16ohms mono and 8 per side stereo...
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#3
E=ir
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#5
Well, the amp has 3 different taps on it's OT. The 16 ohm uses more of the windings on the transformer than the others, and the 8 more than the 4.
You can debate the tonal differences all day regarding which way sounds better, but there's barely a difference at best.

The cab's a different story. I'm going to assume it's a 4x12.

The 4 and 16 ohm settings are just switching between parallel and series-parallel wiring.
This WILL make a difference in sound, though not too significant.

The 8ohm setting has got to be something different.
You have two jacks in the cab, right?
When you set the cab to 8 ohms, you are splitting it into (2) 2x12 parallel wired stereo sides at 8 ohms each. Not very useful.

Personally, I like series parallel wiring, set the cab and amp to 16, bazonga.
#6
As long as you set them to match, it will be fine. But I doubt many cabs will have options for 4, 8 and 16 unless it's both a mono and stereo cab. For example, four 16 ohm speakers could be 4 ohms (parallel) or 16 ohms (parallel-series) but that's it - 8 really isn't an option if you're using all four speakers.
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#7
Thanks for the replies. Sorry I forgot to mention which cab I'm using. It's a Randall 4x12 XL, it doesn't actually have an ohm "switch" it just has two inputs, left for 4 ohm mono, right for 16 ohm mono and both for 8 ohm stereo. I've been using the 16 ohm since I got it, so I guess I'll just stick with that. Thanks again.
#8
didnt want to start a new thread soo...

lemme see if i got this right.

Ive got a head with switchable 4 8 or 16 ohms. Now my cab is only 16 ohms. so i should set the head to 16 right?

what happens if you run the head at 4 or 8 tho?
#9
Quote by TheLastSerenade
didnt want to start a new thread soo...

lemme see if i got this right.

Ive got a head with switchable 4 8 or 16 ohms. Now my cab is only 16 ohms. so i should set the head to 16 right?

what happens if you run the head at 4 or 8 tho?


Right, amp and cab should match. Mis-matches CAN be ok, but are generally to be avoided at all costs, and it VERY much depends on the type of amp (tube or SS) and even on brand.

For example, a Fender Bassman (all tube) can handle MORE impedance at the cab without much trouble, but sounds like ass. LESS impedance will blow it. An Ampeg Reverberocket (all tube) will blow at ANY mismatch. A Roland JC will last for a little while at LESS impedance, and sound like ass, but will likely blow at MORE impedance. Confused yet? Just match it and you'll be good.

What have you got?
If you've got a 4-8-16 selector, just match it and relax.
#10
thanks man. peavey valeking head and 6505 cab. the cab is 16ohms.

so yea ill just match it. im still curious and confused about ohms and that stuff tho, but ill do some research