#2
A 16 ohm speaker can handle more output, it can go louder. You generally want to match amp impedence(ohm's) with speaker impedence. This way your amp and speakers work most efficiently. A 4 ohm amp matched with a 8 ohm cab would work fine, presumably you could turn the amp up all the way and the cab should be able to handle it. but a 16 ohm head (if it exists) matched with a 8 ohm cab would be risky, if you turned the amp up all the way you'd be pretty likely to blow the speakers. You may have already known half of this. I may be wrong about some of it. hope it helped
#3
8 ohms.

Different amps require different loads. An 8 ohm Celestion V30 with an 8 ohm head is designed to run (operate, sound) the same as a 16 ohm Celestion V30 with a 16 ohm head. The only thing you need to know about ohms is that you need to match the number on your head and cab.
You Don't Need a halfstack.

You Don't Need 100W.

Quote by jj1565
i love you slats.
#4
A 16 ohm speaker can handle more output, it can go louder.


Nope. A 8 ohm amp at 50 watts and a 16 ohm amp at 50 watts will both be about the same volume level, if both are using matched speakers, that's determined more by the output wattage and efficiency of the speakers. Speaker efficiency makes a much greater difference in volume than the resistance of the same speaker. You can't hear the difference in volume between a 8 ohm and 16 ohm speaker hooked to the same amp. (I found out long ago without realizing I was running a 4 ohm amp through a 8 ohm cabinet. Switched to a 4 ohm cabinet and couldn't tell any difference.)

a 16 ohm head (if it exists) matched with a 8 ohm cab would be risky, if you turned the amp up all the way you'd be pretty likely to blow the speakers.


Backward.

The speaker would handle it just fine, it's the amp that would suffer. Solid state amps are more forgiving, they can handle mismatched speakers but will still have problems, my old Kustom blew a diode when I hooked up a couple of speakers and didn't know it was only running about a 2 ohm load with an 8 ohm amp.

Tube amps are a lot more picky, a higher resistance speaker shouldn't cause much trouble, it just makes the amp work a bit harder to get the speaker to work, but a lower resistance speaker has a good possibility of blowing the output transformer.

As far as the ohm rating itself, 8 ohm or 16 ohm simply means the speaker presents that much resistance to the amp. Speakers are commonly produced in 4, 8 and 16 ohm versions, I have computer speakers here that are 32 ohm, and I've seen oddball ones like 5 ohm. There should be no difference in sound, that's more a property influenced by the size and travel of the voice coil and type and thickness of the paper cone, and type of magnet.

Oh, 16 ohm heads do exist, as do 2 ohm, which is the output resistance of my Super Reverb. I think the Peavey Classic 30 is a 16 ohm amp, but I'm not positive about that, seems like that's what I read not long ago though, and if you use the external speaker jack it wires them parallel for a total 8 ohm load. Some amps also have a speaker output switch that changes the transformer tap used, so you can set the amp to use 4, 8 or 16 ohm speakers. That lets you use a wider variety of cabinets with the amp.
Hmmm...I wonder what this button does...
#6
ok, my JCM900 head has 2 outputs on it and theres a switch for 8 and 16 ohm`s my cab has 2 inputs ones 8 ohm for mono and then it says 16 ohm`s under both inputs... so if i use both inputs i switch my head to 16 ohm`s right?

i wanna try it because i ran my Line 6 with both output jacks into both inputs and it sounded better.
#7
ELECTRONICALLY SPEAKING...

It is imperative to match amplifier output impedance to a speaker’s nominal impedance. Amps are designed to operate into nominal load impedance. Mismatching amps and speakers risks fatal damage to your amp.

BTW, a speaker offers ZERO resistance. If you ohm out a speaker you will see zero ohms, that’s because your measuring the resistance of the voice coil and all that is is a long wire.

Speakers do not offer any resistance at all to your amps output signal, what it does offer is a reactive load, that is, it changes its reactance or impedance (or simply AC resistance) with whatever frequency it is reacting to. A speaker’s nominal impedance is commonly 8 ohms or 16 ohms…those are ‘nominal’ ratings. You will not measure 8 or 16 ohms…as a matter of fact; the impedance offered to the amp may vary significantly above and below the 8 or 16 ohm ratings. It all depends on the frequencies inputted.

If an amp is designed to operate into a 16 ohm load (speaker), use a 16 ohm speaker. If designed to operate into 8 ohms, give it an 8 ohm speaker.
Trav
#8
Quote by Slayerdeath
ok, my JCM900 head has 2 outputs on it and theres a switch for 8 and 16 ohm`s

my cab has 2 inputs ones 8 ohm for mono and then it says 16 ohm`s under both inputs.


You have a choice to run your amp into an 8 or 16 amp load. You need to determine what load your spkr cab is offering.

If I read you right, your spkr cab has 2 inputs and it’s a stereo cab right?

If I read you right, select 8 ohms on your amp and plug into the 8 ohm input on your spkr cab. Your amp will be driving all spkrs.
Trav
Last edited by Traveler 45C at Mar 12, 2008,
#9
Quote by yoyodunno
My triple xxx has a 16ohm speaker out, but how common are 16ohm cabs?


Pretty common. Peavey, Orange, and Vox (to name a few) are all 16ohm based, and a company like Avatar will load to your specifications.
You Don't Need a halfstack.

You Don't Need 100W.

Quote by jj1565
i love you slats.
#11
^Did nobody actually read Paleo Pete's post? I'd say that covers pretty much everything...

EDIT: ....albeit not entirely correctly.
Last edited by kyle62 at Mar 12, 2008,
#12
^ Yeah, I did.

I'll get to that in a moment ...


Good Grief!
This is one hellacious collection of half-truths and out-right bullshit.



Quote by lp_soldier200
A 16 ohm speaker can handle more output, it can go louder.
WRONG.
El toro poo-poo.
Impedance has NOTHING to do with power handling capability.
Case closed, no discussion necessary.

Quote by slatsmania
8 ohms.

Different amps require different loads. An 8 ohm Celestion V30 with an 8 ohm head is designed to run (operate, sound) the same as a 16 ohm Celestion V30 with a 16 ohm head. The only thing you need to know about ohms is that you need to match the number on your head and cab.
meh, not as informative about how it works as you could have been. You should also know that you can operate safely if they don't match. But you need to know how things work to know how to mis-match safely.

Nothing you said will steer anyone in the wrong direction.
Therefore, much love to you my friend.



Quote by Paleo Pete
Tube amps are a lot more picky, a higher resistance speaker shouldn't cause much trouble, it just makes the amp work a bit harder to get the speaker to work, but a lower resistance speaker has a good possibility of blowing the output transformer.
WRONG
Dead Wrong.
Dead, punched through insulation on the output transformer, WRONG.

UNLIKE a solid state amp
which can handle no load at all or a speaker impedance that is too high...


Too high of a load impedance on a tube amp is most certain way to cause the output transformer and output tubes to fail. Without a load or with a load that has too high impedance on the secondary, the voltage swings on the primary of the transformer will be far in excess of the ability of the insulation to handle. The arcing on the plates of the output tubes won't be doing them any favors either. But at least if the tubes are damaged, they are easily replaced. Not so with the expensive, now useless output transformer.


Think I'm bullshitting you on this one?
Leo Fender doesn't.
Take a look at the Fender Super you so proudly name-dropped.
The secondary of the output transformer gets shorted by the speaker jack,
if nothing is connected.

That's right, SHORTED.

http://www.ampwares.com/ffg/schem/super_reverb_ab763_layout.gif

http://www.ampwares.com/ffg/schem/super_reverb_ab763_schem.gif

Quote by Traveler 45C
BTW, a speaker offers ZERO resistance. If you ohm out a speaker you will see zero ohms, that’s because your measuring the resistance of the voice coil and all that is is a long wire.
WRONG

Have you ever actually MEASURED the resistance of a speaker?

Yeah, I didn't think so.
The resistance of a speaker is always less than the rated impedance.
But NEVER zero.
Typically it's about 3/4 of the rated impedance.


Fact:
The way to get the maximum power your amp can deliver safely it to match the impedance.

Fact:
If you must mis-match impedances on a TUBE amp, it is far safer to have the impedance of the speaker LOWER than the impedance of the amp.

Fact:
Some SOLID STATE amps can operate safely with lower impedance speakers than they are rated for. Their protection circuits will limit the current and prevent damage, although the performance of the amp will be poor. Does your solid state amp have this kind of protection? Who cares! Don't do it. If you must mismatch on a SOLID STATE amp, use a speaker with a GREATER impedance than the amp is rated for.
Meadows
Quote by Jackal58
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#13
Quote by SomeoneYouKnew
meh, not as informative about how it works as you could have been. You should also know that you can operate safely if they don't match. But you need to know how things work to know how to mis-match safely.


When someone starts a thread like this:

Quote by jordan8865
What's the difference between a 8 ohm and 16 ohm speaker?


You'll have to forgive me if I go with the simple answer. I suspect Paleo Pete's post and yours flew over the threadstarter's head high enough for him to need a telescope to hope to discern them.

There's conflicting info out there on mis-matching ohms. The safe option is not to do it.
You Don't Need a halfstack.

You Don't Need 100W.

Quote by jj1565
i love you slats.
#14
I have a fairly simple (though dumb) question about ohms. When it's said to match the Ohms of amp and cab.....is it that you match the Ohms of each individual speaker to the ohms of the amp (so 2 speakers at 8 ohms each you match with an 8 ohms amp), or the combined ohms of the speakers (so 2 speakers at 8 ohms each combining to 16ohms to match with 16 ohms amp)
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Harley Benton 2x12 Vintage 30's
Vox AC4TV
Vox VT15
#15
You match the total load of the speakers to the amp.

Two 8 ohm speakers in series would be a 16 ohm load, while two 8 ohm speakers in parallel would be 4 ohms.
You Don't Need a halfstack.

You Don't Need 100W.

Quote by jj1565
i love you slats.
#16
Quote by slatsmania
You'll have to forgive me if I go with the simple answer.
I more than forgave you, I gave you a

Quote by slatsmania
There's conflicting info out there on mis-matching ohms. The safe option is not to do it.
That's why I'm here. To debunk the BS.

You keep it simple, for those who are willing to make sure things match correctly.
There is nothing really wrong with that.

But there are some times when you have to use what you have, and it doesn't match.
If you use it wisely, you can be safe, even when it doesn't match.

Quote by SurfinWithSatch
I have a fairly simple (though dumb) question about ohms. When it's said to match the Ohms of amp and cab.....is it that you match the Ohms of each individual speaker to the ohms of the amp (so 2 speakers at 8 ohms each you match with an 8 ohms amp), or the combined ohms of the speakers (so 2 speakers at 8 ohms each combining to 16ohms to match with 16 ohms amp)
Not a dumb question at all.

You need to match the total impedance, not the impedance of the individual speakers.

Two 8 ohm speakers wired in PARALLEL will be 4 ohms.

Two 8 ohm speakers wired in SERIES will be 16 ohms.

NEITHER will match an amp that is rated for 8 ohms.
So what do you do, if you must use this? :

1 - Use only 1 speaker. That matches your amp, perfectly.

2a - IF the amp is a TUBE amp, wire them in parallel for 4 ohms.

2b - IF the amp is SOLID STATE, wire them in series for 16 ohm.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#17
[quote="SomeoneYouKnewWRONG

Have you ever actually MEASURED the resistance of a speaker?

Yeah, I didn't think so.
The resistance of a speaker is always less than the rated impedance.
But NEVER zero.
Typically it's about 3/4 of the rated impedance.


NO, YOUR WRONG. Go measure a spkr, come back and report what you find.

The resistance is always less than its impedance...DUH! That is exactly what I said. Zero or should I have gone into it a little deeper. Perhaps you'll see a little bit of resistance...like 1 ohm...maybe. Go check it out. BTW...in the electronics world, 1 ohm is damn close to zero... as far a big current is concerned.

BTW, you really come across as an asshole.
Trav
#18
Ohms are a measurement of resistance. That is basic physics to know that. Less resistence, less of a increase in power to make speakers go to optimum power, therefor 8 ohm cabs are the happy medium, because 16 ohm cabs are for much smaller speakers to get more of a definition out of the small speaker. I own a 4 ohm cab because it is clearer with high powered speakers, but that's not for everyone and saying that 8 ohm cabs are the most popular imedance for cabinets on the market. Most tube heads have impedance selector switchers, or different extension cab jacks for different ohms.
#19
So is it possible to hook up a combo to like a cabinet? as long as they're the same ohms (impedance?)? Are there any other factors? I would hate to blow up my sweet combo lol.
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#21
This leads me to my next question. In my combo I have 2 G12T-75 speakers. However the ohm rating isn't written on the anywhere. The impedence rating on the combo is currently set at 8 and the other option is "4(16)". The amp runs fine so Im assuming if I were to hook up a 2x12 cab at some point I'd have to switch to the 4(16) setting yes?
Gear:
Epiphone SG Standard - Natural Wood Finish + SD Alnico Pro 2 Bridge Pickup
Epiphone Les Paul Standard - Limited Edition Green
Ibanez S470
Blackstar HT-100 Head
Harley Benton 2x12 Vintage 30's
Vox AC4TV
Vox VT15
#22
Quote by SurfinWithSatch
This leads me to my next question. In my combo I have 2 G12T-75 speakers. However the ohm rating isn't written on the anywhere. The impedence rating on the combo is currently set at 8 and the other option is "4(16)". The amp runs fine so Im assuming if I were to hook up a 2x12 cab at some point I'd have to switch to the 4(16) setting yes?


Best advice here is to check your Owner's Manual. It should go into detail on the various hookups available to you.

Normally the impedance of the spkr is stamped on it. I would guess that your spkr's are currently 'wired' for 8 ohms being that it's currently set up like that and you haven’t changed it since buying it.

You have 2 spkrs, therefore you either have 2, 4 ohm spkrs 'wired' in series, that is, the signal goes from the amp’s output to one spkr then the other, (granted this is simplifying the explanation), or you have 2, 16 ohm spkrs 'wired' in parallel, that is, your signal goes from your amp to both spkrs at the same time.

If you were to hook up an external 2x12 cab you'll need to determine what its impedance is then set your amps selector switch accordingly. If it’s an 8 ohm cab you won't have to do anything. Again, check your Owner’s Manual.
Trav
#23
Quote by Erich yeung
So is it possible to hook up a combo to like a cabinet? as long as they're the same ohms (impedance?)? Are there any other factors? I would hate to blow up my sweet combo lol.


Yes, it is ok to hook up a combo to an ext cabinet as long as you match impedances correctly.

Think of your current combo's spkr arrangement as a cabinet. If you have only one spkr in your combo and its impedance is 8 ohms your amp is happy; it is 'seeing' 8 ohms.

If you have a 4x12, 8 ohm cabinet lying around, unplug your combo spkr and plug in to your cabinet. Your amp is still happy; it is still 'seeing' 8 ohms. You will probably hear a difference in that your pushing more air and therefore louder.
Let’s not even go into tone changes or power differences. That is beyond the scope of the question and could lead to further confusion on this issue.
Trav
#24
i know i probably dont know enugh to justify anything i would have to say about amps, which by the way is nothing. BUT it would be ****ING WISE to google THIS **** first, try WIKIPEADIA (spelt wrong sorry) try HOW STUFF WORKS. maybe the manufacurer explains the topic on there amp? and sence just about everyone here is conflicting eachother, which is why I didn't even read past the first page (working on it) it would be wise to go to forums last.

start here: http://science.howstuffworks.com/question501.htm
and here: http://en.wikipedia.org/wiki/Ohm
here too: http://www.guitarbasics.com/guitar_advice/0000080f.htm

and the funny thing is i just did about 3 minuets of googleing. haha try that first so you can get a vallid answer on what your trying to find out.

hope this helps - Something Started

oh sorry about the misspelt words, i'm not at all in the mood of checking them at the moment.
curently composes with Guitar Pro 5. amazing peace of software. i'd recomend it. and Samplitude recording studio.

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#25
I have an RP250 and i love it, even though i just play it through a crate 15w solid-state, it makes it sound like a marshall (if thats what you want it to sound like).