I'm pretty new to seperate amp heads and speaker cabinet, so please excuse my very stupid and basic questions.
Anyhow, I just got an Orange AD30TC head, with their 2x12 cab. On the back of the head, there are three output jacks. 1 for 16 ohms, and 2 for 8 ohms. Which one should I be using for the Orange 2x12? In fact, I have no idea about the concept 8 vs 16 ohms.
Also, on the back of the speaker cab, there are two input jacks. Is this just so that different heads can use the same cab at the same time?<font face='Verdana'></font id='Verdana'>
Amp head --> speaker question
Moderator: bclaire
The cab is most likely 16ohms. It has 2 jacks on the back so you can daisy chain another cab to it.
Don't try running 2 heads from one cab.
2 (16ohm) cabs connected together will give you 8ohms.
Plug the 16ohm cab into the 8 or 16 ohm out.
It will be louder in the 16ohm out, but drive harder on the speakers.
It will be quiter in the 8ohm out, but not drive the speakers as hard.
2 16ohm cabs together is 8ohms, and must go in the 8ohm out, never the 16.
Match the ohms to the output or have a greater number than the output.
eg. A 16ohm out needs 16 or greater ohms. Anything less than 16 is bad, higher is safer.
Running the 16ohm cab in the 8ohm out is safer for the amp and speakers.
Don't try running 2 heads from one cab.
2 (16ohm) cabs connected together will give you 8ohms.
Plug the 16ohm cab into the 8 or 16 ohm out.
It will be louder in the 16ohm out, but drive harder on the speakers.
It will be quiter in the 8ohm out, but not drive the speakers as hard.
2 16ohm cabs together is 8ohms, and must go in the 8ohm out, never the 16.
Match the ohms to the output or have a greater number than the output.
eg. A 16ohm out needs 16 or greater ohms. Anything less than 16 is bad, higher is safer.
Running the 16ohm cab in the 8ohm out is safer for the amp and speakers.
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bclaire
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I've never heard of running a cab with the wrong ohmage setting.
16 ohm cab = 16 ohm speaker out.
8 ohm cab = 8 ohm speaker out.
Even if it can handle it, some amps can't so you should never get into the habit of mismatching impedances or you're going to be in the market for a new output transformer and they are not cheap!!
The cabinet should say right on the back what its' impedance is. Check it out and plug it into the appropriate impedance speaker out. Billy
16 ohm cab = 16 ohm speaker out.
8 ohm cab = 8 ohm speaker out.
Even if it can handle it, some amps can't so you should never get into the habit of mismatching impedances or you're going to be in the market for a new output transformer and they are not cheap!!
The cabinet should say right on the back what its' impedance is. Check it out and plug it into the appropriate impedance speaker out. Billy
Impedance mis-matching.
Let's say you don’t have a 16 ohm output (for the speaker cabinet rated at 16 ohms) and
the head only has options for 8 or 4 ohms? Can it still be run safely? What about the case of using a 4 ohm
cabinet but the amp only has settings for 8 ohms or above?
The answer to the first question regarding whether a 16 ohm cabinet can be run safely with an amp that has
settings for 8 or 4 ohms is yes. However, when running the head at a lower ohm rating then the cabinet, the result
will be a significant degree of power loss. In the second case of using a 4 ohm cabinet with an amp that must be
run at 8 ohms, this will stress an amp and cause it to overheat. Technically, you’ll get more power output (not
efficient or stable power output mind you!) to some degree, but again, at the expense of burning out a
transformer and/or other components. Not a good idea!
Let's say you don’t have a 16 ohm output (for the speaker cabinet rated at 16 ohms) and
the head only has options for 8 or 4 ohms? Can it still be run safely? What about the case of using a 4 ohm
cabinet but the amp only has settings for 8 ohms or above?
The answer to the first question regarding whether a 16 ohm cabinet can be run safely with an amp that has
settings for 8 or 4 ohms is yes. However, when running the head at a lower ohm rating then the cabinet, the result
will be a significant degree of power loss. In the second case of using a 4 ohm cabinet with an amp that must be
run at 8 ohms, this will stress an amp and cause it to overheat. Technically, you’ll get more power output (not
efficient or stable power output mind you!) to some degree, but again, at the expense of burning out a
transformer and/or other components. Not a good idea!
hmmmmmm.... I'm afraid I have to agree with Billy on this one. It's not a good idea to get into the habit of mismatching amps and cabinet ohms. The only company that has ever given the okay to do that on their amps, is Mesa/Boogie. They actually state in their manual, that you will not harm the amp by using different speaker configurations. But they also state that you will experience sound loss, etc. You can even unplug the speaker (which is a HUGE no-no on Marshalls) while the amp is running. I've heard, as Billy stated, that you can seriously fry your output transformer by mismatching the stated ohms on the back of the amp, with the speaker cab. I'm certainly no expert, but I've heard the same thing over and over through the years.
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bclaire
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I had a bandmate fry the output transformer in his Marshall years and years ago when he used a defective speaker cord and just left it on- doh. Amp wasn't happy and neither was he when he discovered that an output tranny was $175. That was in the 70's. They've gone up since then.
Fenders and Boogies seem to be the exception- they seem happy to go with whatever cab you're using. But when it comes to Oranges, it's time to err on the paranoid side and use 16 with 16, 8 with 8, 4 with 4.
I run a Marshall speaker emulator between my head and cab these days- for one, to knock down the sound, for two to get an emulated line out, and three if the cab somehow doesn't get plugged in or whatever, the emulator will step up to the plate and attenuate the whole load. Nice!
Billy
Fenders and Boogies seem to be the exception- they seem happy to go with whatever cab you're using. But when it comes to Oranges, it's time to err on the paranoid side and use 16 with 16, 8 with 8, 4 with 4.
I run a Marshall speaker emulator between my head and cab these days- for one, to knock down the sound, for two to get an emulated line out, and three if the cab somehow doesn't get plugged in or whatever, the emulator will step up to the plate and attenuate the whole load. Nice!
Billy
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