Running mismatched OHM cabinets.

[thiswaythatway]

As we all know it's safe to run say, an 8ohms out from you amp into a 16 ohm cabinet. Or 4ohm into 8ohm cab. Has anyone ever run 2 cabinets of different OHMs? For example an 8 OHM cab and a 16 OHM cab with one amp? An 8 OHM cab and a 16 OHM cab calculated together in parallel are 5.3 OHMS so if were to run 4 OHMS out from my amp I think I'd be ok. But does anyone run a setup like this? And is there really any noticeable tone differences when running an amp with all the same loads as opposed to the setup I mentioned with safe mismatches?

 

[rupe]

I can't believe you don't know the answer to this...rookie.

 

[thiswaythatway]

I've just never run different cabs like that. I think you'd run into a problem like this with a Marshall amp that only has 8 and 16 OHM selections.

 

[sleeperaxe]

I have run a setup like this (combo amp with 8 ohm speaker plus 16 ohm extension cab), and I've noticed no difference tonally. I'm not an amp tech, but I've done my reading, and it seems like a perfectly safe way to run an amp.

I think you could also run an 8 ohm output into a 5.3 ohm load. I believe one of the old tweed Fenders with 3X10 speakers did this. I think it was a Bandmaster. I've seen posts on other forums stating that this actually makes the amp sound better because it makes the OT work a bit harder. I have no idea whether that's true though.

 

[rupe]

I've just never run different cabs like that. I think you'd run into a problem like this with a Marshall amp that only has 8 and 16 OHM selections.

I was being facetious...I'm clueless. It's a good question

 

[Buckeyedog]

You would be safe, but the 8 ohm cab would take twice the power than the 16 ohm cab.

 

[steve_k]

Danny,

If you have an output selector, like on a Marshall, the speaker jacks are all assigned to an equivalent output. So, if you set it to 4 ohms, you can plug in your 8 and 16 ohm cabs for an equivalent of 5.3 ohms and be fine as this fixed output is assigned to the 4 ohm tap on the OT.

If, you are doing this with an amp that has fixed output to the jacks (like a MESA), you need to be careful and I wouldn't recommend it long term. Those 2-8 ohm jacks are wired to the 8 ohm and 4 ohm taps of the OT. Current is taking the path of least resistance and is constantly changing with those cabs pulling unevenly. Theoretically, it cannot dip below 4ohm, and you should be fine. However, this mismatch could put some stain on the OT running out of balance.

I just asked this very question of an amp guy on one of my mods. Then again, MESA says its OK.....I wouldn't do it as a rule. But, if you aren't straining the output of an amp, it would likely be fine.

 

[glpg80]

Theres only one topic i have ever mentioned electronically why it is a bad idea to mix cabinets. Not going to do it again, but the technician that steve spoke to is correct - it is also my same point of view. Can you do it? Yes - but remember impedance in this purpose is for max power transfer of AC. You're testing the quality of the transformer and depending on how it is wired, not all amplifiers are a definite "you're fine".

 

[John4021]

Good thread. I used to run a 2x12 and a 4x12 into a Mesa.
No problems,but since my amps have changed,I really dont want to risk it.
Be a real bitch to smoke a tranny(ok,,,start the jokes) .

 

[Anonymous]

You would be safe, but the 8 ohm cab would take twice the power than the 16 ohm cab.

yes, the 8 ohm cab will be louder in that situation pulling 5.333 with an 8 and 16 and your head set on 4
ive done it with no problems, and for a long period of time. i actually liked it at first for a while, but then didnt like the mismatch in sound and tone...i wanted to hear more of the bottom cab (16), so i did some switching.

ironically, the only issue i ever had with an amp OT going was when i had the ohms matched up 8/8!!

 

[moltisanti]

check how your cabs are wired, it takes about 5 minutes to rewire from series to parallel and vice versa, so you may easily be able to get them matching

 

[thiswaythatway]

check how your cabs are wired, it takes about 5 minutes to rewire from series to parallel and vice versa, so you may easily be able to get them matching

Not if my combo is running 8 OHMS and I wanted to throw 2 Lynchbacks in another 2x12 cabinet. Those speakers only come in 8 OHMS. Great for a 4x12, but not a 2x12.

 

[BackCrack]

You could wire those two Lynch's in series to give a 16Ω load, then you'd have the 16Ω + 8Ω = 5.33Ω scenario as previously mentioned.

 

[sleeperaxe]

You can also get a Weber Z Matcher if it's a major concern.

 

[ke2]

Mesa all but encourage you to mismatch in the older Mark series manuals
How it works on the later models, I'm not sure.

 

[AmpliFIRE]

So going by this thread, if my cabs are 16 ohm and 8 ohm I should be running both of them into the 4 ohm inputs of my 2:90?

 

[D-Rock]

I only do this with my Mesa amps. the manual says they can handle it.
No other amp manufacturer has ever said theirs can as well.

 

[bravedude2]

i fucked up my VL1002 and my DSL 100 by running them on 16 ohm and 8 ohm cab

 

[Shark Diver]

You could also wire the 16 ohm to daisy chain to a Hot Plate or such at 16 ohm. 16+16 = 8. then run at 4 ohms with the combo.

Not perfect, but load correct.

 

[rupe]

So going by this thread, if my cabs are 16 ohm and 8 ohm I should be running both of them into the 4 ohm inputs of my 2:90?

Only if running both cabs off of one side of the power amp. The 2:90 is essentially two independent power sections...nothing in this thread applies to running both sides of it. If you are running both sides with one cabinet, you would simply use the appropriate ohm setting. I had this exact same scenario and that's how somebody at Mesa explained it to me.