OT/Speaker mismatch

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LarsenGuitars
Posts: 2
Joined: Sun Jul 19, 2009 3:25 pm
Location: Tinley Park, IL

OT/Speaker mismatch

Post by LarsenGuitars »

Hi all, I've been a silent observer here for a while and have learned a lot. Planning to start a D'lite build soon. One thing I've always been a little confused about is mismatches with the OT and speaker cab. I've heard you can run higher impedance cab on lower impedance OT, I've heard it the other way. Have not been able to find a definitive answer on this subject.

Thanks,

Paul
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Structo
Posts: 15446
Joined: Wed Oct 17, 2007 1:01 am
Location: Oregon

Re: OT/Speaker mismatch

Post by Structo »

Depending on the amp and output transformer quality it is generally considered safe to use a mismatch one step above or one step below the amp setting.
So a 8 ohm amp into a 16 ohm speaker or a 8 ohm amp into a 4 ohm speaker load.

Old Fenders could take that kind of mismatch easily.
But some of the newer amps may not be too happy with a mismatch.

They also sound different than matched impedance and load.

I suppose the best way is to just try it and play it loud for a while then feel the output transformer.
If it feels pretty hot to the touch then perhaps it is not happy with the mismatch.
Tom

Don't let that smoke out!
talbany
Posts: 4696
Joined: Tue Mar 28, 2006 5:03 am
Location: Dumbleland

Re: OT/Speaker mismatch

Post by talbany »

LarsenGuitars wrote:Hi all, I've been a silent observer here for a while and have learned a lot. Planning to start a D'lite build soon. One thing I've always been a little confused about is mismatches with the OT and speaker cab. I've heard you can run higher impedance cab on lower impedance OT, I've heard it the other way. Have not been able to find a definitive answer on this subject.

Thanks,

Paul
Paul
That's because there is no definitive rule here (To a Point)..Speaker matching is done with a 1K signal only, not the full spectrum of a guitar so it's an imperfect measurement..IMO..

Output impedance as it relates to tone and max transfer is more of a guideline than a hard fast cross this line your shit will blow rule..If you search through the site there are many posts/threads about some cause and effects of impedance mismatching how it effects tone and output transformers and know there are boundaries here...learn them and you will be fine.. If your unsure.... stick with matching..

Tony
" The psychics on my bench is the same as Dumble'"
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LarsenGuitars
Posts: 2
Joined: Sun Jul 19, 2009 3:25 pm
Location: Tinley Park, IL

Re: OT/Speaker mismatch

Post by LarsenGuitars »

Thanks guys! I am not in a situation where i would need to mismatch, just trying to fill some of the knowledge gaps.
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