Will a 16 ohm cab hurt my 8 ohm amp?

  • Thread starter Thread starter Uladine
  • Start date Start date
Uladine

Uladine

New member
I was told it was an 8 ohm cab at the store. Low and behold I get it home and its a 16 ohm cab. Will this hurt anything or do I have to rewire the cab to run at 4 ohms? My amps manual says 4 ohms and 8 ohms is ok, 2 ohms is bad, but it doesnt say anything about 16 ohms. Thanks for any help. Id rather not plug everything in until I find out everything is ok.
 
the cab only runs 16 ohms?? that sux, bring it back or buy another so you can run 8 ohms. That salesman blows, were did you get it ? guitar center or mars??
 
Relax Dude the amp is going to like 16 best, It will run cooler and not work the amp as hard. they will not be as loud as an 8 or 4 but your amp will last alot longer for using them
 
Run cooler yeah, but you;re gonna have to pump up the volume to get some balls which is contradictory in a way...
I prefer the sound of a 4 ohm or 8 ohm setup the best, and you;ll get the best use, especially from a 50-watt head, using a 4 ohm cabinet. A 50 watt head with a 16 ohm cabinet is OUT when it comes to live band jamming, forget about it.
 
If its a tube amp, it should have seperate outputs for different ohm cabs... do NOT run a cab lower than the output setting, though higher is ok. Just thought I;d mention that...
 
it's not going to damage an 8ohm amp to hook up a 16ohm but it's not what you should do

BUT, this is what you'll get:

a 16 ohm cabinet will only deliver 1/4 the power output as the 8ohm cabinet, not 1/2 the power.

with the 16ohm cabinet/8ohm-head you'll need to turn up the amp volume a lot more to get an equivalent sound level.

the amp output transformer wants to see an 8ohm load, not a 16ohm load. impeadance mismatches shorten AMP life not prolong it.

check and you may find out the amp output transformer has a 16ohm tap, if so then it's just a matter of moving two wires.

the amp will run cooler if you don't jack the input Vol up to compensate for the significantly reduced Volume. you'll end up running the Volume at a much higher level, so in the end the amp won't run cooler. actually it's stressed more do to the impeadance mismatch. again, the output transformer wants to see an 8 ohm load!!!

recommendation, get a 8ohm cabinet or get a 16ohm head or see if the Amp has a 16ohm tap.

-kp-
 
Would it be a good idea to maybe rewire the cab to a 4 ohm speaker configuration. I heard this is easily done with cabs that have 4 16 ohm speakers by wiring them in parrallel. Would this hurt anything? I'm not jamming with a band yet because we're looking for a new practice place, but I'd like to remedy this situation as best I can before I need to crank the amp.
 
Correction Ohms law says if you Increse the resistance by 2 you only cut power by 1/2. I havent had a problem with my system But Ive got a 100wat amp head. And It still rules the room.
 
But it CAN damage a 16 ohm tap plugging into a 4 ohm load, keep that in mind.
 
1st Choice......and the best one; Go back to the shop and get them to sort it out. If the head is new and there is no mention of using a 16 ohm quad in the manual you may void any warranty. Anyway it sounds like the sales guy screwed up.

2nd Choice; If there isn't a possible warranty issue and it is 2nd hand gear contact a qualified tech and get him to guide you.

Peace........ChrisO :cool:
 
Another thing is you cannot get an Eight ohm,4 ohm or16ohm amp for that matter. those Parameters are for the loads. Many Amps do not have the 16 ohm parameter on its outputs because the cabinets arent as popular as 4, and 8 ohm models. and the ratings of output power would be low enough make the specs look bad.

You will still have no trouble Being the loudest in the room and keeping your amp cool, I sure as hell dont. and we play loud.
 
OK, I've been going through this today with my amps. I discovered that my "Evil Twin" was switched to 4 Ohms and the standard speakers are 16 Ohms. Switched it back where it was supposed to be according to the manual, i.e., 16 Ohms.

My Ampeg has 8- and 16-Ohm output settings and has a 16-Ohm box.

If a 16-Ohm box is hooked up to a head with the output switched to 16 Ohms, will it have less output than the same amp running into an 8-Ohm box with the head switched to 8 ohms?
 
In theory it should be about the same; the 8-ohm match might be a little punchier because the speaker array is offering less resistance - but who knows whether you would hear a practical difference. The key is to find a match within the amp's "comfort" range. If you have a bad mismatch, the best that will happen is poor sound. The worst - running a low resistance cab with a higher rated amp - is a blown amp. Don't try to mess with it if you need the amp... get a tech to look at it.

As I understand it, you can do a quick mathematical calculation of resistance this way. You can calculate the ohm rating of an array by looking at its components and the manner in which they are wired. For instance, (4) four - ohm speakers can be wired in parallel, in series, or in two arrays of parallel drivers which are then wired in series (or the other way around, I suppose).

If you are wiring in series, the resistance is additive. So the four speakers wired in series will yield 4 + 4 + 4 + 4 = 16 ohms.

If you wire in parallel, you calculate the resistance as the common denominator reciprocal of the additive ratings. I think that means that these four speakers wired in parallel would yield 4/4 (or 1/1), the denominator of which is 1: a 1 ohm array. Maybe. Hard2Hear, help me out here. It's not supposed to get into whole numbers. Maybe we don't have to go there; I don't plan on wiring anything up for a while anyhow... (whew)

Let's try an array of twin drivers wired in parallel. 2/4 = 1/2: 2 ohms. Lets put two of them together in series. 2 ohm array + 2 ohm array + 4 ohms.

Let's try the opposite. Twin drivers wired in series, connected with another identical array: the two of them wired in parallel. 4 + 4 = 8; so each twin driver array is 8 ohms. Wire the arrays in parallel and you get 1/8 + 1/8 = 2/8 = 1/4: Still a 4 ohm array. Huh? Yup. Like a Rubik's cube of sorts.

Now try the same exercise with 8-ohm drivers. You should get in order, the following results:

32 ohms

2 ohms

8 ohms

8 ohms

That is, unless I've got it wrong...

Maybe that's why amps are rated for such a broad range of resistance.


:D
 
Most 4/12 cabnets are wired series/parralell. so most of the time the whole cabinet has an 8ohm rating as does the indiviual speakers.

I have found that most vintage style speakers have a 16 ohm rating,Im not sure why but output tubes last longer with them Installed.
 
Well I wasn't able to bring the cab back for an 8 ohm one because the only 8 ohm ones they had were marshalls, and their quite a bit more expensive than the ampeg I got for $250. I didnt want to bridge the amp because when our other guitar player gets his preamp we're going to share the same rack and and power amp. So I rewired the cab in parallel and tested it out. It was noticebly louder, so I think it did the trick. This may void the warranty on my cab, but I got it for $250, so I wont loose any sleep over it. I'm not worried about the amp much because it has built in security measures against improper loads. Thank you all for your input. I'm gonna go piss off the neighbors now.
 
>>If a 16-Ohm box is hooked up to a head with the output
>>switched to 16 Ohms, will it have less output than the same
>>amp running into an 8-Ohm box with the head switched to 8
>>ohms?

>In theory it should be about the same;

Yes, the Fender docs say that there''s a straight 100W output on any of the three output settings.

Still, there are a lot of people who insist that this isn't so for some reason. If there are any here, I should like to hear their technical explanations.

I think they are misunderstanding some single-impedance amp output figures that show outputs of X Watts into 4 Ohms and X-Y Watts into 8 Ohms, when there is no adjustable impedance settings on an amp with a nominal 4 Ohm output.
 
. So I rewired the cab in parallel and tested it out. It was noticebly louder, so I think it did the trick.
Click to expand...

Um... want to take an extra step, just to be sure? Stick a meter on the cab and measure the resistance? You get too low and the amp will begin to, uh, "age" quickly...
 
tubedude said:
A 50 watt head with a 16 ohm cabinet is OUT when it comes to live band jamming, forget about it.
Click to expand...

Sorry, man, but thats just wrong, might be like thgat for some amps, but not all. I run my JCM800 2205 50 watt at 16 ohms into the 16 ohm input of my 1960 cab. I don't even attempt turning the thing up past 6 in a VERY loud band situation where my other guitarist has a Mesa Dual rectifier turned up to 6 also (and thats 100 watts running at 8 ohms). A lot of 50 watt TUBE amps are REALLY LOUD. I could run the amp at 4 ohms, (the cab has a 4 ohm input, and the amp has a selectable impedance output), but I figure it isn't needed to run the amp that hot and possibly limit its lifespan. It really doesn't sound that much different at 4 either.

Jake
 
Bongolation

to ANSWER that you would look at dB not watts as a parameter.

Anybody notice that Vintage Replacement speakers are always 16 ohm?
 
You must log in or register to reply here.
Back
Top