Help figuring out Impedance.

[mischief8869]

Can someone help me. i bought a used 2x12 cabinet with two 16ohm speakers. Looks like it was modded to have three speaker jacks on the back instead of just two. Just trying to figure out the labels. how many ohms per jack and which jack etc. Basically trying to figure out how to set the impedance. I'm sorry I've always owned combos this is my first cab and head.

 

[ehdwuld]

Re: Help figuring out Impedance.

Plug in a speaker cable to each jack
Read the tip and sleeve with a multimeter set to ohms

 

[GuitarStv]

Re: Help figuring out Impedance.

Plug in a speaker cable to each jack
Read the tip and sleeve with a multimeter set to ohms

Does that work? I never get 8 ohms when I try to read an 8 ohm speaker. I thought the resistance was very frequency dependent.

 

[JB_From_Hell]

Re: Help figuring out Impedance.

What is your cabinet's impedance?

 

[DavidRavenMoon]

Re: Help figuring out Impedance.

That doesn’t look wired correctly. It looks like they are in series, which would be 32 ohms.

What impedance is your head? Are you using another cab?

I’d rewire those in parallel for 8 ohms and have both going to the same two jacks. The second jack is usually for daisy chaining another cab, unless it’s a stereo cab.


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[mischief8869]

Re: Help figuring out Impedance.

What is your cabinet's impedance?

the head can be set to 4,8, and 16 ohm. as far as the cab i am not sure. originally it was 8 ohm but since its been modified ive been trying ro figure it out

 

[mischief8869]

Re: Help figuring out Impedance.

That doesn’t look wired correctly. It looks like they are in series, which would be 32 ohms.

What impedance is your head? Are you using another cab?

I’d rewire those in parallel for 8 ohms and have both going to the same two jacks. The second jack is usually for daisy chaining another cab, unless it’s a stereo cab.


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the head can be set to 4 8 and 16 ohm.
thats what i was thinking of maybe re wiring them, but i was hoping to not have to do it.

 

[Jacew]

Re: Help figuring out Impedance.

Does that work? I never get 8 ohms when I try to read an 8 ohm speaker. I thought the resistance was very frequency dependent.

Yes. It's not accurate but close enough to make sure. Usually couple ohms lower than spec.

 

[JB_From_Hell]

Re: Help figuring out Impedance.

the head can be set to 4,8, and 16 ohm. as far as the cab i am not sure. originally it was 8 ohm but since its been modified ive been trying ro figure it out

I meant to say head, not cab.

I'd pick an impedance, and rewire the cabinet to match. Unless you're swapping to different heads with different impedances a lot, there's not much reason to have multiple options.

 

[jeremy]

Re: Help figuring out Impedance.

are the speakers 16 ohms? cant see from the pic. it looks like originally they had two 16 ohm speakers wired in parallel for 8ohms and a parallel jack for running another cab. now it looks like one speaker is wired to two jacks (allowing a parallel connection to another cab or the other speaker) and the other speaker is wired only to one jack. maybe the previous user was running stereo or multiple amps into the one cab?

 

[mischief8869]

Re: Help figuring out Impedance.

are the speakers 16 ohms? cant see from the pic. it looks like originally they had two 16 ohm speakers wired in parallel for 8ohms and a parallel jack for running another cab. now it looks like one speaker is wired to two jacks (allowing a parallel connection to another cab or the other speaker) and the other speaker is wired only to one jack. maybe the previous user was running stereo or multiple amps into the one cab?

yes, they are both 16ohm speakers. i was kind of thinking they were running it stereo. as if each speaker was its own 1x12 cab. if thats the case, woulidnt i need to set my amps impedance to 16ohm? or would having two 1x12 cabs be 32ohm?

 

[JB_From_Hell]

Re: Help figuring out Impedance.

yes, they are both 16ohm speakers. i was kind of thinking they were running it stereo. as if each speaker was its own 1x12 cab. if thats the case, woulidnt i need to set my amps impedance to 16ohm? or would having two 1x12 cabs be 32ohm?

If they’re wired series, two 16ohm loads gives you 32. If they’re parallel, it’s 8.

Set your head to 8, wire them in parallel, and don’t worry about the other options... unless you’re into that

 

[jeremy]

Re: Help figuring out Impedance.

yes, they are both 16ohm speakers. i was kind of thinking they were running it stereo. as if each speaker was its own 1x12 cab. if thats the case, woulidnt i need to set my amps impedance to 16ohm? or would having two 1x12 cabs be 32ohm?

i think if you plug into the top jack, then jump the two others with a short speaker cable you should get both speakers in parallel. pita way to do it but quick if ya wanna try it. hardwiring it in parallel is a good plan unless you wanna run the speakers separate

 

[PFDarkside]

Re: Help figuring out Impedance.

i think if you plug into the top jack, then jump the two others with a short speaker cable you should get both speakers in parallel. pita way to do it but quick if ya wanna try it. hardwiring it in parallel is a good plan unless you wanna run the speakers separate

This is what it looks like. The two bottom jacks can be used for dual 16 ohms (stereo), or plug into the top jack and use a short jumper between the bottom two for a single 8 ohm cabinet (both speakers).

 

[mischief8869]

Re: Help figuring out Impedance.

Thanks everyone for the help, i think ill just end up re wiring them parallel for 8ohms. Would anyone have a diagram to wire them parallel with a second Jack for daisy chaining.

 

[ibanezrocks]

Re: Help figuring out Impedance.

Does that work? I never get 8 ohms when I try to read an 8 ohm speaker. I thought the resistance was very frequency dependent.

IIRC speaker impedance is measured at 400Hz. It'll be lower measured at DC (what a multimeter gives you).

The numbers should be close enough for you to figure it out. An 8 ohm speaker will read around 6 ohms at DC.

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[JMP/HBE]

Re: Help figuring out Impedance.

The cab of fail ...