8 or 16 ohm loads

dirtycooter · Post by **dirtycooter** » Wed Dec 10, 2014 10:20 pm

So this may have been discussed before I am sure.
But I have a question here regarding the use of attenuators and the ohm load prefered.
Whats the consensus
8tap to 8ohm att to 16ohm cab?
Or 8tap to 16ohm att to 16ohm cab??

Any two cents here or insight all welcome.

efraser68 · Post by **efraser68** » Wed Dec 10, 2014 11:42 pm

DC I am 8tap to 16ohm att to 16ohm cab

jnew · Post by **jnew** » Thu Dec 11, 2014 1:47 am

Me too. Always sounded right to me with either of my amps.

JimiJames · Post by **JimiJames** » Thu Dec 11, 2014 2:53 am

same here

Jeremy1283 · Post by **Jeremy1283** » Thu Dec 11, 2014 3:42 am

Im at a 4ohm tap. 16 ohm load: 16 ohm cab

echoplexi1974 · Post by **echoplexi1974** » Thu Dec 11, 2014 8:44 am

Do you hear a tone difference when setting the impedance of the amp lower than the attenuator/cabinet?

jnew · Post by **jnew** » Thu Dec 11, 2014 12:35 pm

Jeremy1283 wrote:Im at a 4ohm tap. 16 ohm load: 16 ohm cab

Yeah but remember, You have a 100 watt OPT Trans with a 1.7K primary and you have 2 tubes pulled. So properly matched, you would run the amp at 8 ohms into a 16 ohm cab for two tubes. So your amp with two tubes pulled at 4 ohms is the same as 4 tubes being on 8 ohms into a 16 ohm load.

dirtycooter · Post by **dirtycooter** » Thu Dec 11, 2014 5:04 pm

I tried two tubes, 4 into 16. Yikes it was bright and bottomless for me. 8-16 sounded like it was more right on my amp. Even with 4 tubes it sounded better than 4-16. 8-16 load re-amped has it best as well when in that route.
Bottom gets more correct, hights cut a bit different, total sound compresses a bit and the amp fries a little harder.

Jeremy1283 · Post by **Jeremy1283** » Thu Dec 11, 2014 5:07 pm

That is my experience so far.. BRIGHT! lol
I just putt the hfb on the ohm selector so i can adjust it on the fly. Thanks dc for the advice

jnew · Post by **jnew** » Thu Dec 11, 2014 5:10 pm

That's about exactly as I would expect. With 2 tubes, 4 ohm amp to 16 ohm load should be the same as 4 tubes, 8 ohm amp to 16 ohm load though.

Brad737 · Post by **Brad737** » Mon Jan 26, 2015 10:29 am

I guess I'm a moron, but I run my amp at 16 ohms, into the attenuator, into a 16 ohm cabinet. Please forgive my ignorance, but why would one intentionally mismatch the load?

I originally did that with a Bluesbreaker, because I'd read that's what EC did, but then I read it was potentially harmful, so I matched it.

Thanks,
Brad

jnew · Post by **jnew** » Mon Jan 26, 2015 10:53 am

I don't get that. My amps are always mismatched (by one step only) and I would argue that the tone is not brighter. The amp behaves a little differently with SAG and feel and the lows are held together a little better with punctuality. Harmful? I seriously doubt that. I'm near 5 years with it this way and recently bought a tube tester. Tubes tested outstanding but I also run at 90VAC which I would also argue, actually prolong tubes.

If they died today, I would be more than pleased. Hell, I'd be happy with this even if I only got a year out of them.

dirtycooter · Post by **dirtycooter** » Mon Jan 26, 2015 10:49 pm

Everything Jnew said and then some. Even MesaBoogie has a tutorial stating the mismatch can have tonal benefits. 8 into 16 is just a heavier load than 8-8. Maybe works the transformer and parts more.
Think of it as a gear reduction. Like when you pedal your mountain bike. 8-16 is like trying to climb a hill with big long hard pushes on the pedal. In a smaller gear you will have all kinds of power to climb the hill but have to pedal way faster to stay movin. 8-4 would be like pedeling so fast your legs burn up and fall off and we know thats the wrong kinda mismatch. There is hardly no resistance and tour amp has nothing to push gainst and it hyper speeds itself into complete burnout. You aren't as hot with big long pushes on a bike pedal but pedaling as fast as possible you will wear out in no time. This 8-4 WILL make magic smoke.
Somehow though I am prefering 16-16 suddenly now but am getting less sag effect than 8-16 but my mids and body seem fuller at 16-16. I may revert back to 8-16 maybe.

Carbia · Post by **Carbia** » Wed Jan 28, 2015 7:23 am

I like the amps with matched impedance.

16 on 16 is the best to me

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