Can you run a 16 and an 8 ohm cab together?

[Kristian Ford]

Pardon my lack of knowledge in this area, but is it possible?
Searches were vague..
Doesn't seem ideal..

[a.hun]

It is possible, but not ideal.
(All mismatches from valve amps lower efficiency - power output drops, and change the tone at least a little. There is also always *some* additional risk, especially if a weak valve or amp component is involved. You have to decide if the risk is worth it to you. In this case the risk is fairly minimal.

Wiring a 16 and 8 cab together (in 'parallel' = normal speaker linking) gives a total load of 5.33 ohms. Since most healthy valve amps will survive a mismatch from 1/2 to 2x (half to double) correct matching impedance you could run this from either a 4 or an 8 ohm amp output fairly safely. The mismatch ratio (the important thing here!) is actually the same either way (either 1/3 high or 1/3 too low). Safer to run from an 8 ohm output though as lower direction mismatches - while harder on the power valves - are MUCH less likely to cause amp damage than high direction ones. 8 ohms is your only option here with a modern Orange anyway, the vintage ones also had 4 ohm outputs though.

Important: NEVER run from the different impedance outputs on an amp at the same time!

Be aware that since the cabs have different impedances they'll draw different proportions of the amp's power. In this case the 16 ohm cab will take 1/3 of the amp's power, the 8 ohm cab the remaining 2/3.

If you want to do it, do it. (Own risk of course, nothing is guaranteed) Correct matching is always better, but if you know what you are doing a bit of deliberate creative mismatching can be okay. See my mate John P's advice here for example:
http://www.thegearpage.net/board/index. ... mp.245463/" onclick="window.open(this.href);return false;


Andy.

[Kristian Ford]

Thanks Andy!
Well, it's for my '75 OR120, which does have 4/8/16, but if it's hard on the power valves, (which an OR120 already is!) I think I will just find a 16 ohm cab.

[a.hun]

Seems fair!


Andy.

[bclaire]

Thanks Andy!
Well, it's for my '75 OR120, which does have 4/8/16, but if it's hard on the power valves, (which an OR120 already is!) I think I will just find a 16 ohm cab.

For a vintage Orange the answer should be definitely no....

[a.hun]

For a vintage Orange the answer should be definitely no....

I'd say for the '90s reissues indeed, just don't mismatch! Their (otherwise good performing) transformers really didn't like it and many blew.
Never really heard of special mismatch problems with the original '70s ones though. Other than what I've already mentioned above of course.


Andy.

[megalithic]

You could probably do it on the Micro Terror, it has 4 ohms minimum and just one jack with no switch.

I run it on 4 ohms daily (2 8 ohm speakers in parallel) and don't have any problems.

However, having tried something like this before with another amp, I can say that the 8 ohm speaker will be twice as loud than the 16 ohm speaker, so I'm not sure how useful this would be.