Changing speaker ohms
- Thread starter Mikelamury
- Start date
Mikelamury
New member
Ok thanks for the help with that do it's looking like I might not be able to hook both cabs up together but I guess I can use them separately or maybe replace one of the v30's with the A type...
well, you can, but it wont be the same impedance. almost any time you mix two cabs, you are always doing so in parallel wiring. within one cab, you can have series or parallel wiring. you need to understand how mixing impedance, whether its two speakers, or two cabs, works before going any further to save yourself some frustration
Mikelamury
New member
I was assuming that the 2 v30's we're both 8 ohm but I'm not sure I will find out. So is it not possible to have 2 8 ohm speakers in a cab needing 8 ohms of resistance from the amp?
correct. 8 + 8 can either be 16 ohms (in series) or 4 ohms (in parallel). you can mix an 8 ohm speaker with a 16 ohm speaker in a cab but you end up with an impedance that is outside of what amps usually want to see. doesnt mean it cant be done, but should be done with caution and understanding of what you are doing and how your amp will deal with it and how the mismatch will dictate how the speakers interact
devastone
New member
Probably best to stick to basics, no, it's not a good idea to mix impedances.
Yes, but it also splits the power to the speakers unevenly.
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Mikelamury
New member
Your right. I'm beginning to understand how impedance/resistance works, I have a question how are the speakers usually wired in a 4x12 cab?
Mikelamury
New member
Can you please explain how you get 16 ohms of resistance from the 4 speakers? What are the resistances of the 4 speakers? By series/parallel do you mean two are wired in series and 2 in parallel? Forgive me for all the questions I'm trying to get the math down for calculating total ohms or impedance.
devastone
New member
As he said, the speakers are 16 ohms each. 2 sets of 2 are wired in parallel, so 2X 8 ohm loads, then those are wired in series to give a total of 16 ohms.
https://www.electronics-tutorials.ws/resistor/res_3.html
https://www.electronics-tutorials.ws/resistor/res_4.html
https://www.electronics-tutorials.ws/resistor/res_5.html
https://www.electronics-tutorials.ws/resistor/res_3.html
https://www.electronics-tutorials.ws/resistor/res_4.html
https://www.electronics-tutorials.ws/resistor/res_5.html
Mikelamury
New member
Thanks for the links that was very helpful of you. I saved those if I need to go back to them but I now have a better understanding of the matter. Thank you and everyone else that helped me to learn about this and answered the annoying newb questions there is a first for everything it's kind of embarrassing to not have learned this earlier as I've been playing since I was 14 but I've needed to connect speakers before as I used cheap SS combo practice amps for most of the time I've been playing i just recently was able to afford tube amps.
NegativeEase
New member
You can change the speaker cab to hold to whatever speaker and speaker impedance you want -but you want to see the options of the output of your amplifier feeding it to match that ideally -and that depends on how the transformer is tapped and broken out.
GuitarStv
Sock Market Trader
Resistance is Ohms law baby!
Parallel:
1/Rtotal = 1/R1 + 1/R2 + 1/R3 . . . etc.
Series:
Rtotal = R1 + R2 + R3 . . .
So with 4 16 ohm speakers you do this:
Parallel:
1/R12 = 1/R1 + 1/R2
1/R12 = 1/16 + 1/16 = 2/16 = 1/8
So we know the resistance of speaker 1 and 2 in parallel is 8 ohms.
Same equation works out to the same value for the resistance of speaker 3 and 4 in parallel - 8ohm
Then you wire the parallel speakers 1/2 and 3/4 in series with each other to get:
Rtotal = R12 + R34
Rtotal = 8 + 8
Rtotal = 16 ohms
Simple!
GuitarStv
Sock Market Trader
After my degree I know how to integrate, derivate, do matrix algebra, calculate heat and mass transfer, and use Laplace transforms . . . but almost the only thing I've applied in the real world is Ohms law.
eclecticsynergy
Well-known member
16 Ohms from a 4x12 cab with four 16 Ohm speakers is quite common. The series/parallel thing sounds confusing, but it just means two pairs.
Two of the speakers are wired in series to give 32 Ohms impedance. The other two are wired the same.
Then the two 32 Ohm pairs are wired in parallel with each other to give an overall cabinet impedance of 16 Ohms.
Two of the speakers are wired in series to give 32 Ohms impedance. The other two are wired the same.
Then the two 32 Ohm pairs are wired in parallel with each other to give an overall cabinet impedance of 16 Ohms.
