#1
Hey, hope everyone's Christmas was great!
I don't know much about ohms, and whatever information I find has to do with 4 or 2 speaker cabinets. I have a cabinet with 6 ten inch speakers in it and the speakers are (I think) rated at 8 ohms. Does this mean that the head running the cabinet should be 8 ohms, or is it not that simple? Thanks in advance
#2
Yes, if the cab says the overal ohms is 8 total then that is all you need to really worry about. Set you amp to 8 my friend. If you want more detail than that you would probably need to tell us what cab it is and give us some pics of the wiring etc.
#3
You aren't clear. Is the cab 8 ohm or are the individual speakers 8 ohm? If the latter then you'll have to look at how they are wired up to calculate the overall impedance.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#4
There are 6 ten-inch speakers, and each speaker is separately rated at 8 ohms each.
Okay, here's what the wiring looks like. I know you can't quite see the one top speaker on the left side if the cabinet, but it simply has a red wire on the left terminal and a white wire on the right terminal. The cabinet itself is the cabinet portion of the Silvertone 1465 from 1968 I'm just looking for a simply way to power it, maybe by using an Electro-Harmonix 44 Magnum power amp, but I don't want to cause any damage to either component because of ohms mismatching...
First photo is right 2 speakers, second photo is middle 2 speakers, and last photo is left 2 speakers. I am unsure if it is wired in parallel or series, hoping you guys can help me out
Attachments:
1227110503.jpg
1227110504.jpg
1227110504a.jpg
Last edited by tucci66 at Dec 27, 2011,
#5
Those photos are awful. i can't see what is connected to what in those little things.
It will be one of these two arrangements (but with two extra speakers).


Parallel


Series-Parallel

Identify which one it is and come back.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#7
That video isnt very clear either. Two options i see. 1st get a peace of paper and draw out the schematics of what you find in the cabinet. start at the jack and trace the wires to wherever they go and draw it up. Then post that sketch.

Next option is to run to radio shack and just get a multimeter.

http://www.radioshack.com/product/index.jsp?productId=4214667
#8
Yeah, I think I misread the OP. I thought you were saying the cab was 8 total. Cathbard is right. And yes, the pics (and vid) are hard to tell.

Getting a multimeter is a good idea and a good tool to have in life anyway. It won't give you the exact impedance but it will get you in the ballpark. Enough to determine the difference between 4 ohms and 8 ohms for example.

Drawing up the wiring is a good idea. If I had to guess, I'd say the cab is wired in series/parallel.

There are 3 main ways to wire a speaker cab:
Series - basically you just connect all the speakers one right after the next and it forms a big loop (like in Cathbard's diagram). I doubt this would it because you would have 8+8+8+8+8+8=48 ohms. I doubt that is right.
Parallel - basically the negative terminals are connected together and the positive terminals are connected together. In this scenario you divide down to determine total impedance. I'm not even sure what that would look like with 6 speakers but I can get you a formula to use.
Series/Parallel - this is most likely. Basically you wire each set (or pair of speakers) together in parallel and wire those pairs together in series. The problem with this is that I believe the resulting impedance would be 12 ohms. That may not be a big deal - you would set the amp at 8.

Series/Parallal
8 + (parallel) 8 = 4
8 + (parallel) 8 = 4
8 + (parallel) 8 = 4

4 + (series) 4 + (series) 4 = 12


Here is a diagram depicting Series/Parallel wiring for a 4x12.



^ that is just an example I didn't write all of that out for this particular circumstance. Based on your first pic, I'd say Series/Parallel is most likely.
Last edited by 311ZOSOVHJH at Dec 27, 2011,
#9
You can even ignore that dc resistance isn't equal to impedance in this instance. Disconnect one speaker and measure the resistance across it. Then reconnect it and measure the resistance across the input jack.
Now you have all the figures we need to tell you how it's wired up and what the total impedance is.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band