Author Topic: OHM Impedance  (Read 3888 times)

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Offline .amy.

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OHM Impedance
« on: October 21, 2006, 08:34:42 pm »
I need some help here.....confused!

I have a Sunn Sorado head and just bought a Fender Bassman cabinet....well the Sunn head says 8 ohm speaker and 4 ohm external speaker; and the cabinet says 8 ohm speaker and 4 ohm total. Are these compatable? Can someone explain all this to me? I've heard so many different things I'm not sure which information to go with! I've always used the Sorado with the 215B Sunn cabinet and that is rated at 4 ohms for the system impedance; 160w overall. Everything sounds fine but AM I FUCKING SHIT UP!?

Offline mc2

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Re: OHM Impedance
« Reply #1 on: October 22, 2006, 11:35:02 am »
I need some help here.....confused!

I have a Sunn Sorado head and just bought a Fender Bassman cabinet....well the Sunn head says 8 ohm speaker and 4 ohm external speaker; and the cabinet says 8 ohm speaker and 4 ohm total. Are these compatable? Can someone explain all this to me? I've heard so many different things I'm not sure which information to go with! I've always used the Sorado with the 215B Sunn cabinet and that is rated at 4 ohms for the system impedance; 160w overall. Everything sounds fine but AM I FUCKING SHIT UP!?


OK....Your SUNN head...each of the two outputs are labeled for thier rating if you plug in ONE matching cabinet with the same rating AT A TIME. If you need to plug in TWO cabinets to the head at the same time, each one should ideally be 8 Ohms...and when you plug each into the two rear jacks, the Sunn head combines the two in parallel automatically and actually makes each jack 4 Ohms to match.  It sounds like your Fender cabinet has a couple internal 8 Ohm speakers that are wired internally for a total cabinet resistance of 4 Ohms at the jack. So, if you are only using that one Fender bottom with the Sunn head, you would plug it into the output on the head marked 4 Ohms.

Offline .amy.

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Re: OHM Impedance
« Reply #2 on: October 22, 2006, 05:04:37 pm »
"So, if you are only using that one Fender bottom with the Sunn head, you would plug it into the output on the head marked 4 Ohms."

but it says 4 ohm external speaker. a friend of ours says that you have to go from the 8 ohm outlet on the head into an 8 ohm cabinet and that will activate the 4 ohm external speaker side on the head. is this true? i just don't want to ruin the head. HELP!!!!!

Offline JoeArthur

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Re: OHM Impedance
« Reply #3 on: October 23, 2006, 08:41:10 am »

Some amps are wired the way your friend suggests, but not this one.

The extension speaker jack is the one that does the switching.  The other speaker jack is in parallel - just ignore what they are called and you'll be fine.

Offline .amy.

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Re: OHM Impedance
« Reply #4 on: October 23, 2006, 02:47:10 pm »
sooooo........do i plug it into the 8ohm or the 4 ohm external speaker?

Offline JoeArthur

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Re: OHM Impedance
« Reply #5 on: October 23, 2006, 03:13:25 pm »

The 4 ohm external speaker.

Offline .amy.

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Re: OHM Impedance
« Reply #6 on: October 23, 2006, 05:21:35 pm »
ohhhh ok. i've been playing through the 8 ohm all along. do you think i damaged anything? will there be any sound difference between the two jacks? man.....this shit is confusing! haha