Re wiring my Marshall cab

[winter_fires]

Hey guys
I need to re-wire my 16 ohm Marshall cab so that it will have a 4ohm load.
Does anyone have any diagrams or able to tell me how i would do this.
Thanks in advance.

[kafka]

What does it have in it? 4 x 16ohm speakers? If that's the case, they would currently be wired in series/parallel or parallel/series. Just wire all 4 in parallel, which will give you 4 ohms. Also, make sure the polarity of all of the speakers is lined up or they'll be working against each other. (i.e. the tip of the input jack goes to all the positive terminals, and the sleeve goes to all the negative terminals)

[Tim Greer]

Originally Posted by winter_fires

Hey guys
I need to re-wire my 16 ohm Marshall cab so that it will have a 4ohm load.
Does anyone have any diagrams or able to tell me how i would do this.
Thanks in advance.

Is this a 4x12 or 2x12 cab? How many ohms are the current speakers each?

[winter_fires]

It is a 4x12 and the speakers are 16 ohms each.
any suggestions?

[Farview]

Kafka has it right. Tip goes to all the positive terminals on the speakers and sleeve goes to all the negative terminals.

[Tim Greer]

This page has a visual, if you need it:

Wiring a 4 X 12 Speaker cabinet

Specifically: http://www.colomar.com/Shavano/4x12wiring1.gif

[velvetgeorge]

Series-Parallel at 16 ohms is correct for vintage Marshall 4-12 cabs.

The above link is correct for 4 ohm wiring.


George

[winter_fires]

Thanks alot. that is really helpful.

[matskull]

My new (to me) cab looks like it's wired in serie/paralel but I just wanna be sure.

Mine looks like the picture, why doesn't it look like the drawning?
(this isn't my cab but the wiring is identical)
my speakers are 8ohm and the cab is suposed to be wired into 8ohm also.

[matskull]

nobody knows?

[Iggy Poop]

Your picture shows it wired in series. That's not what you want. Look closer at your diagram. It shows all positives wired together and all negatives wired together then back to the terminals.

[matskull]

Originally Posted by Iggy Poop

Your picture shows it wired in series. That's not what you want. Look closer at your diagram. It shows all positives wired together and all negatives wired together then back to the terminals.

But the wires that connect the left and right side are going from positive to negative...
Is it really in serie like that!?!

I searched the internet and found a couple of pictures of marshall cab wired like this, mine says it's 8 ohm and the speakers are all 8 ohm.

thanks

[Iggy Poop]

I thought you said you had 16 ohm speakers. If you have (4) 8 ohm speakers I don't believe you can get a final value of 4 ohms. When you wire (2) 8 ohm speakers in parallel their value becomes halved (4 ohms). When you series (2) 8 ohm speakers together their value becomes doubled (16 ohms). if you had 16 ohm speakers you could wire each 2 speakers in parallel (value 8 ohms) and then parallel those 2 sets together (final value 4 ohms).

[matskull]

Originally Posted by Iggy Poop

I thought you said you had 16 ohm speakers. If you have (4) 8 ohm speakers I don't believe you can get a final value of 4 ohms. When you wire (2) 8 ohm speakers in parallel their value becomes halved (4 ohms). When you series (2) 8 ohm speakers together their value becomes doubled (16 ohms). if you had 16 ohm speakers you could wire each 2 speakers in parallel (value 8 ohms) and then parallel those 2 sets together (final value 4 ohms).

Yeah my speakers are 8 ohm each and the cab is suposed to be wired in 8 ohm total.
So I think that this is a serie/paralel wiring, 2 pair in paralel which gives 4 ohm for each pair and those two pairs wired together in serie for a total of 8 ohm.

I just don't really understand why the picture doesn't look like the drawning...

[Iggy Poop]

I can't tell which terminals are positive or negative on the speakers. Can you get your meter and measure the resistance on the circuit to verify the ohms?

[matskull]

Originally Posted by Iggy Poop

I can't tell which terminals are positive or negative on the speakers. Can you get your meter and measure the resistance on the circuit to verify the ohms?

I'll try to borrow one.
thanks