# 16 Ohm Speaker Sounds Better?



## ampaholic (Sep 19, 2006)

In an effort to squeeze a bit more headroom out of my amp I installed a 16 ohm speaker. The amp will accommodate either 8 or 16 ohm loads.
The theory is that a 16 ohm speaker will utilize 100% of the output transformer whereas the 8 ohm speaker only uses half.
I'm not set up to do an A/B test but I'm convinced that the amp sounds better too. Is it my imagination or have others experienced this?


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## fogdart (Mar 22, 2017)




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## nonreverb (Sep 19, 2006)

ampaholic said:


> In an effort to squeeze a bit more headroom out of my amp I installed a 16 ohm speaker. The amp will accommodate either 8 or 16 ohm loads.
> The theory is that a 16 ohm speaker will utilize 100% of the output transformer whereas the 8 ohm speaker only uses half.
> I'm not set up to do an A/B test but I'm convinced that the amp sounds better too. Is it my imagination or have others experienced this?


Well in theory, one's a match for the transformer/tube combination's impedance and one isn't unless it also has an impedance switch. Are the two speakers the same type/brand?


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## player99 (Sep 5, 2019)

I though it went the other way. To have an amp louder at a lower volume setting 4 ohms would be the one. 16 ohms would have less volume so the amp gets turned up, reducing the headroom.

edit: Assuming the amp is what breaks up.


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## Latole (Aug 11, 2020)

ampaholic said:


> I'm not set up to do an A/B test but I'm convinced that the amp sounds better too. Is it my imagination or have others experienced this?


With no A/B test ; you can't say .
Are both speaker and cab are same ?


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## fogdart (Mar 22, 2017)

Latole said:


> With no A/B test ; you can't say .
> Are both speaker and cab are same ?


Even this isn’t entirely accurate, because two of the same speaker could be slightly different. The only way to do it is with a 2x12 cab that is wired 4ohm and then wired 16ohm. This way you’re using the same speakers and cab for both tests.

See the video I posted - it’s got the answer.


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## Latole (Aug 11, 2020)

fogdart said:


> Even this isn’t entirely accurate, because two of the same speaker could be slightly different. The only way to do it is with a 2x12 cab that is wired 4ohm and then wired 16ohm. This way you’re using the same speakers and cab for both tests.
> 
> See the video I posted - it’s got the answer.


I agree


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## ampaholic (Sep 19, 2006)

Both Celestion speakers. The 8 ohm a G12H - 55 (well broken in) and the 16 ohm a brand new G12H Anniversary. Both in the same single 12 Dr Z cabinet. No impedance switch on the amp.
Doing an A/B comparison is complicated. Again, it may be my imagination or perhaps just wishful thinking that the new speaker was a wise choice!


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## Griff (Sep 7, 2016)

With no impedance switch on the amo, what makes you think it is optimized at both 8 and 16 ohms?

In my experience, using the wrong impedance for an amp lowers the actual volume/output...


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## loudtubeamps (Feb 2, 2012)

The correct answer is the the speaker that sounds best to you.


My


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## gtrguy (Jul 6, 2006)

ampaholic said:


> The 8 ohm a G12H - 55 (well broken in) and the 16 ohm a brand new G12H Anniversary.


I would expect two different models (even of the same family) to sound slightly different. Not to mention that one is broken in and the other isn't.... there are bound to be differences.


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## jb welder (Sep 14, 2010)

ampaholic said:


> Both Celestion speakers. The 8 ohm a G12H - 55 (well broken in) and the 16 ohm a brand new G12H Anniversary. Both in the same single 12 Dr Z cabinet. No impedance switch on the amp.
> Doing an A/B comparison is complicated. Again, it may be my imagination or perhaps just wishful thinking that the new speaker was a wise choice!


You are hearing differences of the speakers, and difference between impedance match and mismatch.
Those are big differences. Compared to those, the slight difference between the OT taps with all other factors being equal would have been slight in comparison.

To really compare the sound of the taps, like in the video @fogdart posted, you would have to use a pair of speakers, and the same speakers for both tests (changing between series and parallel wiring). And you would need an amp with an impedance switch to maintain the match.

Ideally one other factor should have been controlled for, which may account for the difference they heard in the video. The NFB wire should have been moved when switching taps.


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## nonreverb (Sep 19, 2006)

ampaholic said:


> Both Celestion speakers. The 8 ohm a G12H - 55 (well broken in) and the 16 ohm a brand new G12H Anniversary. Both in the same single 12 Dr Z cabinet. No impedance switch on the amp.
> Doing an A/B comparison is complicated. Again, it may be my imagination or perhaps just wishful thinking that the new speaker was a wise choice!


There will be a difference regardless of the speaker. If you're placing a 16ohm speaker through an 8 ohm output transformer (if I'm understanding correctly that it is an 8ohm output), the reflected impedance is twice as high as the plate impedance. Voltage goes up, current goes down. That will affect the tone and to some degree the output power as well.


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## ampaholic (Sep 19, 2006)

nonreverb said:


> There will be a difference regardless of the speaker. If you're placing a 16ohm speaker through an 8 ohm output transformer (if I'm understanding correctly that it is an 8ohm output), the reflected impedance is twice as high as the plate impedance. Voltage goes up, current goes down. That will affect the tone and to some degree the output power as well.


Not to flog this to pieces but just to clarify. The amp designer/builder (BC Audio, San Francisco) recommends using either an 8 or 16 ohm load but suggested trying the 16 ohm speaker because an 8 ohm load would only use half of the output transformer. Hence I assumed that the transformer is designed for a 16 ohm load but is ok with 8. He does not recommend a 4 ohm load.
Thanks for all the feedback. Bottom line is that the amp always sounds fantastic no matter which speaker I use!


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## nonreverb (Sep 19, 2006)

ampaholic said:


> Not to flog this to pieces but just to clarify. The amp designer/builder (BC Audio, San Francisco) recommends using either an 8 or 16 ohm load but suggested trying the 16 ohm speaker because an 8 ohm load would only use half of the output transformer. Hence I assumed that the transformer is designed for a 16 ohm load but is ok with 8. He does not recommend a 4 ohm load.
> Thanks for all the feedback. Bottom line is that the amp always sounds fantastic no matter which speaker I use!


Well, if the combination sounds better and it's designed for full power @ 16ohm it's a win!


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## alwaysflat (Feb 14, 2016)

If the Output transformer is optimized for 16 ohm load, then yes, an 8 ohm speaker would shift the load line , resulting in a actual plate load of half of the design value, due to a lower reflected load. A lower load from optimum will increase thd and the 2nd order distortion, The original post seemed misleading in statement of using half the transformer , so I thought I'd try to help clarify what made sense to me. I expect you should also have some extra power, to go along with some reduced power stage distortion if, per the engineer, this is closer to optimum.


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## ampaholic (Sep 19, 2006)

alwaysflat said:


> If the Output transformer is optimized for 16 ohm load, then yes, an 8 ohm speaker would shift the load line , resulting in a actual plate load of half of the design value, due to a lower reflected load. A lower load from optimum will increase thd and the 2nd order distortion, The original post seemed misleading in statement of using half the transformer , so I thought I'd try to help clarify what made sense to me. I expect you should also have some extra power, to go along with some reduced power stage distortion if, per the engineer, this is closer to optimum.


Yes, I think my OP may have been misleading. I'm not sure the builder actually implied that an 8 ohm speaker only uses half the transformer (likely just my interpretation) but rather that a 16 ohm speaker would better optimize the output transformer resulting in a tiny bit more power and slightly increased clean headroom. So, not how much of the transformer is being used but rather _how_ it's being used.


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