Lower the ohms...raise the wattage?

Tony Palmer · Post by **Tony Palmer** » 16 Nov 2001 4:57 am

Everything else being equal, if you hook up a speaker with half the ohm value, will you double the amp's wattage output?
If the answer is yes, will it now distort?
Here's what I'm getting at: if you have a tube amp with a good sound, but low wattage, can you juice it up by replacing the speaker with a lower ohm value?

Jack Stoner · Post by **Jack Stoner** » 16 Nov 2001 5:34 am

Not always true.

Maximum power is transferred when the two devices are at the same Impedence (resistance). If the output of the amp (output transformer) is 8 ohms then an 8 ohm load (speaker) will give you the most power. A 4 ohm speaker (load) in this particular case would lose some volume level (how much would depend on the particular amp and speaker).

With a direct coupled transistor amp, the lower the impedence load - down to the amps rated minimum load - will produce more power and loudness.

In a low power amplifier a load mismatch will be much more apparent than a high power amp (many times in a high power amp, just increasing the volume level will take care of any change in the sound level).

Donny Hinson · Post by **Donny Hinson** » 16 Nov 2001 9:56 am

Tony, if it were that simple, it would have been done!!!

Stick with what the manufacturer used, that guarantees the maximum life out of the amp. If you need more power, go to a more efficient speaker...and then let it go at that.

"Yeah man...it was really blastin', but it only lasted a week!"

You don't want that now, do you?

Len Amaral · Post by **Len Amaral** » 16 Nov 2001 3:17 pm

Hi Tony:
Tube amps are different animals as they seem to respond differently with speakers than with solid state amps. Some tube amps have an ohmage switch on the back for 4/8/16 ohms. I have never seen a solid state amp with an omage switch. That doesn't mean that it doesn't exist I just havn't seen one.
I have been swapping speakers in my solid state amps and a 4 to 8 ohm speaker can make a drastic difference. However, a more efficient speaker can make a drastic difference even in the same ohm catagory.
I changed the 4 ohm speaker to an 8 ohm speaker in my Evans SE-200 and the power dropped way down. However, I plugged an 8 ohm
speaker in the speaker extension jack and the amp got a boost as it dropped the overall load back to 4 ohms.
All this stuff gives me a head ache sometimes!...*L*[This message was edited by Len Amaral on 16 November 2001 at 03:18 PM.]

Bobby Lee · Post by **Bobby Lee** » 17 Nov 2001 7:45 pm

My Mesa/Boogie amps have separate jacks for 4 vs. 8 ohm loads. They attach to different leads coming from the output transformer. The amps don't respond as well if you hook up 8 ohms to the 4 ohm speaker or vice versa. I've done it by accident several times, and had a hard time "getting my tone".

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Bill C. Buntin · Post by **Bill C. Buntin** » 20 Nov 2001 6:21 am

What Donny said! If I could afford something with the efficiency and sound of say a Klipsch, WOW! What a speaker. But Klipsch are SO pricey but they truly sound better than any speakers I've ever heard in my 25 years of being an "AUDIOPHILE"!

Michael Brebes · Post by **Michael Brebes** » 20 Nov 2001 3:14 pm

The best way to look at it is:
If it has an output transformer(tube amp) then ohms needs to be matched to specs or there will be a loss in power or possible burnout of the output transformer.
If it is transistor output then it is voltage based, which means that wattage approximately doubles each time you cut the resistance in half. You do have to remember that most transistor power amps will give a minimum resistance or impedance rating.