Ohms Amps and Cabinets

[Masquerade]

Someone explain this to me in the simplest of terms

I still don't understand how this stuff works

So lets take for instance I have a EvH iii Mini thats hooked up to a PPC412

Would I set the head to 8Ω and use both input jacks in the back of the cabinet? (Which is 16&#937


This is probably the easiest thing to understand but its just not making sense to me
Thanks

 

[Yo_Wattup]

16 ohm on amp, though one jack on cab. Check to see if all speakers are working by putting your face next to each one. If not, turn off amp quickly

 

[Masquerade]

So even if you only use one jack, all the speakers will work?

 

[hairychris]

Don't do that.

Just use 1 x 16 ohm output into 1 x 16 ohm input on the cab. Orange cabs have parallel jacks so can be used to pass through to another cab.

If you use 2 cabs @ 16 ohms, you should use 2 x 8 ohm outputs from the amp.

Putting a higher resistance output from the amp into a lower resistance cab you can fry your amp.

 

[Yo_Wattup]

Don't do that.

Just use 1 x 16 ohm output into 1 x 16 ohm input on the cab. Orange cabs have parallel jacks so can be used to pass through to another cab.

If you use 2 cabs @ 16 ohms, you should use 2 x 8 ohm outputs from the amp.

Putting a higher resistance output from the amp into a lower resistance cab you can fry your amp.

Ahhh.... That's what I said...

 

[hairychris]

Ahhh.... That's what I said...

Almost.

But also confirming that the inputs were parallel, therefore should drive all speakers.

I'll admin that I should not have said "Don't do that", or rather meant the original post.

 

[TheWarAgainstTime]

One of the jacks on the Orange is an input and the other is an output to daisy chain to another cab.

Run one output of the EVH at 16ohms into one of the jacks on the Orange. Done

 

[Masquerade]

Awesome, thanks for clarifying guys

 

[Thanatopsis]

Make sure you don't run it without anything plugged in though. Tube amps need to see a load or you could fry the output transformer.

 

[chassless]

highjacking the thread, i had my amp set to 16 ohm by mistake, plugged in my 2x12 rated at 8 ohm and played for about a couple of hours. i didn't notice anything wrong, but is this enough to have damaged anything?

 

[wheresthefbomb]

highjacking the thread, i had my amp set to 16 ohm by mistake, plugged in my 2x12 rated at 8 ohm and played for about a couple of hours. i didn't notice anything wrong, but is this enough to have damaged anything?

I accidentally ran my legacy 1 and 16 ohm into my cab set at 8 ohm and it fried the fuk out of it. nasty electrical fire smell and everything. fortunately, it was fixable, though it cost me $200. lesson learnt.

 

[chassless]

^ well at least that turned out well. how long did you play it on the wrong settings though?

 

[TheWinterSnow]

All speaker outputs on mono amplifiers are in parallel to each other. On a mono cabinet, the inputs are parallel too, rendering one input an input and the other an output to another cabinet.

If you have a 16 ohm cabinet, set the amp to 16 ohms, plug in into any one of the inputs of the cabinet. If you have a stereo cabinet, plug into the mono input and set the amp to 8 ohms.

You don't need to use two cables.

 

[hairychris]

highjacking the thread, i had my amp set to 16 ohm by mistake, plugged in my 2x12 rated at 8 ohm and played for about a couple of hours. i didn't notice anything wrong, but is this enough to have damaged anything?

If it still sounds OK, you're probably still good. You find that you're losing volume and/or definition then you may need it looked at.

What burns out is the output transformer. I killed that on a Marshall by stupidly plugging an 8ohm per side stereo cab into 16ohm outputs for multiple rehearsals at high volume. It died expensively.

 

[chassless]

thanks! it looks like it will be fine, nothing seems wrong up til now.

 

[Mike]

Well since I still don't see a clear answer on the whole Amp/Cab Ohm matching, here's my explanation:

Impedance is measured in (&#937 Ohms. Impedance determines how much current will flow through a component. A very high impedance allows a small amount of current to flow (i.e. a 16 ohm speaker load draws less current than an 8 ohm amp is ready to supply, but it will work safely). A very low impedance allows a large amount of current to flow (i.e. a 4 ohm speaker load draws too much current from an 8 ohm amp, ultimately overheating the amp).

Unacceptable Ohm Mismatches: When connecting any amplifier to an external cabinet it is important to keep in mind that the ohm load of your cabinet should not be lower in number than the ohm rating of your amplifier (which can cause the amplifier to fail). I.e. - If the amp output has an overall rating of 8 ohms DO NOT run with an external cab that has an overall rating of 4 ohms.

Acceptable Ohm Mismatches: It is acceptable to run the overall ohm load output of an amplifier to a cabinet that is higher in number. I.e. If your amp output has an overall output rating of 8 ohms you can run into an external cabinet that has an overall rating of 16 ohms. Be aware that you will lose ~15-20 percent of perceived volume with solid state power amplifiers when running this type of ohm mismatch, but you will suffer no failures. Ideally, try to match the ohm values of your amp and cabinet (I.e. 8 ohm head with 8 ohm cabinet) to ensure the best performance without putting dangerous strain on your gear.

 

[wheresthefbomb]

^ well at least that turned out well. how long did you play it on the wrong settings though?

It happened immediately when I switched the standby off, it had been warming up during the previous band's hour-long set, though, set wrong the whole time. Probably just building up and waiting to pop. Once I opened the floodgates, it was quick to smokey devastation.

 

[glpg80]

Impedance Mismatching, Improper Loading, and More.