OHM mismatch crisis!

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OHM mismatch crisis!

Post by robnobcorncob »

Here we go, Chaternator kindly lent me a cab and I'm going to be using the speakers with my 2 celestions in the same cab. So I have 2x8 ohm speakers and 2x16 ohm speakers. How can I wire these up? the 8ohm ones are currently wired in Parallel for 4 Ohms and the 16 ohms wired series for.... 32 :roll:

How about, if I wire the 2x 8ohms in parallel for 4 ohms and the 2x16 ohms parallel for 8 ohms then I wire both of those in series for 12 ohms I can run it from an 8 ohm load and it'll be sweet. Right?

I just wanna triple check (and explore every available option) so I don't overlook something blatantly obvious and damage a transformer.

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Re: OHM mismatch crisis!

Post by handsoffmatt »

robnobcorncob wrote: How about, if I wire the 2x 8ohms in parallel for 4 ohms and the 2x16 ohms parallel for 8 ohms then I wire both of those in series for 12 ohms I can run it from an 8 ohm load and it'll be sweet. Right?
Yes, this will be a safe mismatch, however....

1) You will not get the full power output from your amp

2) The two 8-ohm speakers will run slightly louder than the two 16-ohm speakers.
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Re: OHM mismatch crisis!

Post by Some Bozo »

Ohm my god !
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Re: OHM mismatch crisis!

Post by Jenesis »

Some Bozo wrote:Ohm my god !
Ohm man... :roll:

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Re: OHM mismatch crisis!

Post by robnobcorncob »

NZRS_Matt wrote:
robnobcorncob wrote: How about, if I wire the 2x 8ohms in parallel for 4 ohms and the 2x16 ohms parallel for 8 ohms then I wire both of those in series for 12 ohms I can run it from an 8 ohm load and it'll be sweet. Right?
Yes, this will be a safe mismatch, however....

1) You will not get the full power output from your amp

2) The two 8-ohm speakers will run slightly louder than the two 16-ohm speakers.

How much difference is Slightly? The 16 ohms are 75 watts each, the 8 ohm speakers I'm not sure of, possibly 30 or 50watt each

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Re: OHM mismatch crisis!

Post by handsoffmatt »

robnobcorncob wrote:
NZRS_Matt wrote:
robnobcorncob wrote: How about, if I wire the 2x 8ohms in parallel for 4 ohms and the 2x16 ohms parallel for 8 ohms then I wire both of those in series for 12 ohms I can run it from an 8 ohm load and it'll be sweet. Right?
Yes, this will be a safe mismatch, however....

1) You will not get the full power output from your amp

2) The two 8-ohm speakers will run slightly louder than the two 16-ohm speakers.

How much difference is Slightly? The 16 ohms are 75 watts each, the 8 ohm speakers I'm not sure of, possibly 30 or 50watt each
It's hard to say just how much different they will sound, but there will definitely be a difference. The wattages of the speakers have no bearing on the volume differential - it is all dependant upon the impedances.

There is no way unfortunately to evenly balance the four speakers you have in ANY configuration.
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Re: OHM mismatch crisis!

Post by rocklander »

X-pattern for the win...

oh and ... om!
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Re: OHM mismatch crisis!

Post by Jenesis »

Om!

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Re: OHM mismatch crisis!

Post by dayl »

I'm just jumping here to save a new thread on this topic.

I suck at this stuff.

I am looking at a Peavey Shefield 12" which is 16ohm rated at 75w continuous

Say I want to put it in a 50w amp. I know I am going to lose some juice. The thing is, that I have always been told that the amp should have more power than the speakers to avoid overworking the amp?

I know it's pretty much101 stuff but this is new to me. I have tapped into the online resources but they are zapping my chi with all this ohm law talk at such an early stage.

Can it be done safely without damage to the amp? I don't care about losing output as I understand that tone isn't effected dramatically or at all.

enlighten me please :)

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Re: OHM mismatch crisis!

Post by Ironbird13 »

you want the speakers to be a higher wattage than amp but the same Ohmage as amp
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Re: OHM mismatch crisis!

Post by Bg »

dayl wrote:I'm just jumping here to save a new thread on this topic.

I suck at this stuff.

I am looking at a Peavey Shefield 12" which is 16ohm rated at 75w continuous

Say I want to put it in a 50w amp. I know I am going to lose some juice. The thing is, that I have always been told that the amp should have more power than the speakers to avoid overworking the amp?

I know it's pretty much101 stuff but this is new to me. I have tapped into the online resources but they are zapping my chi with all this ohm law talk at such an early stage.

Can it be done safely without damage to the amp? I don't care about losing output as I understand that tone isn't effected dramatically or at all.

enlighten me please :)
Perfectly fine, I regularly play a 30 watt amp into a 300 watt cab... Your amp will still put out 50 watts no matter what rating the speaker is - it doesn't care, it will put out 50 watts even if there's no speaker there, though obviously your o/p transformer will melt.

You want to overwork the amp - or do you just want to play clean? I think you're confusing it with PA systems where its better to have a higher spec amp than the speakers. The inverse is true with guitar amps.

Where confusion comes in is with speaker break up - some speakers breakup so nicely that you really want to be pushing them to the limit, but as far as regular ceramic speakers, no problem...
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

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Re: OHM mismatch crisis!

Post by dayl »

bluesgeek wrote:
You want to overwork the amp - or do you just want to play clean? I think you're confusing it with PA systems where its better to have a higher spec amp than the speakers. The inverse is true with guitar amps.
Spot on, this goes back to my DJ sound system setup days. Thats really good to hear. Yes I want break up :) I want a bit of clean, but if I want to record clean, I'll just use my JC-77

Thanks for the advice

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Re: OHM mismatch crisis!

Post by RobRoyMcCoy »

robnobcorncob wrote:Here we go, Chaternator kindly lent me a cab and I'm going to be using the speakers with my 2 celestions in the same cab. So I have 2x8 ohm speakers and 2x16 ohm speakers. How can I wire these up? the 8ohm ones are currently wired in Parallel for 4 Ohms and the 16 ohms wired series for.... 32 :roll:

How about, if I wire the 2x 8ohms in parallel for 4 ohms and the 2x16 ohms parallel for 8 ohms then I wire both of those in series for 12 ohms I can run it from an 8 ohm load and it'll be sweet. Right?

I just wanna triple check (and explore every available option) so I don't overlook something blatantly obvious and damage a transformer.
You could also consider running the 2 x 8 ohms in series for 16 ohms and the 2 x 16 in series for 32 ohms, then parallel up both pairs for 10.7 ohms.

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