4 Ohm amp 8 ohm box

LaFleur

Joined: May 20, 2009
Posts: 525
Leipzig
Germany

Posted on Jul 17 2010 04:48 AM

My new amp has 4 ohms and the box 8ohm(meassured 5.4ohm)?
Does this work? What will happen technically?

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Bilge_Rat

Joined: Apr 20, 2009
Posts: 320
Toronto, Ontario Canada
1 News Pin

Posted on Jul 17 2010 09:10 AM

I wouldn't worry about it.

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formerly SvD, bots.... member since 2006. Same game different name!

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JeffH

Joined: Apr 17, 2010
Posts: 97
PA

Posted on Jul 17 2010 08:09 PM

Usually not a problem - what kind of amp? Although I don't gig, I run old Fender amps with mismatch both ways (4>8ohm, and 4>2 ohm) and haven't had any trouble.

Running into a higher impedance cab is said to be easier on the tubes.

I think if you're talking about a solid-state amp, it's a different story.

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gawfshot

Joined: Jul 03, 2010
Posts: 38

Posted on Jul 19 2010 11:42 PM

"low into high, it will fly... high into low, it will blow"

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bluez

Joined: Jul 11, 2010
Posts: 135
Norway

Posted on Jul 20 2010 03:08 PM

The reason why you are messuring 5,4 ohm is that you are messuring the DC resistance of the voice coil. 8 ohm is the average AC resistance from the resonase frequency of the speaker and usually up to the break up frequency.

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SlacktoneDave

Joined: Jul 01, 2006
Posts: 657
1 News Pin

Posted on Jul 26 2010 08:12 AM

gawfshot
"low into high, it will fly... high into low, it will blow"

A friend of mine took only 15 minutes to blow the 2 -ohm transformer in a mint brown Fender Concert Amp when he played it into a 16-ohm Marshall cabinet.
He was probably pushing the amp pretty hard when that happened. I think amps sound better with properly matched speaker/amp combinations.

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rotnroby

Joined: Mar 31, 2010
Posts: 877
Santa Barbara Ca... in the 805
1 POTD Pin

Posted on Jul 28 2010 02:36 PM

SlacktoneDave

gawfshot
"low into high, it will fly... high into low, it will blow"

A friend of mine took only 15 minutes to blow the 2 -ohm transformer in a mint brown Fender Concert Amp when he played it into a 16-ohm Marshall cabinet.
He was probably pushing the amp pretty hard when that happened. I think amps sound better with properly matched speaker/amp combinations.

I totally agree.. Never the less if your output Transformer is 4-ohms and your cabinet is rated @ 8-ohms you'll be fine however if your output transformer is rated @ 4-ohms and your running a 16-ohms cabinet your gonna heat up that transformer to were you just might do some damage... Good thing we all pay good attention to details..

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LaFleur

Joined: May 20, 2009
Posts: 525
Leipzig
Germany

Posted on Aug 09 2010 08:35 AM

I also connected another 8 ohm cab parallel to the Surfers Tone-Ring cab(so now its 4 ohm).

Its really huge difference in sound!!! Its a lot louder and a way more dynamic than 4ohm amp into 8 ohm box.

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guitarslinger1

Joined: Oct 29, 2007
Posts: 185
Pacifica, CA
1 News Pin

Posted on Aug 09 2010 09:26 AM

Hi everyone, question ...can you use 3 8 ohm speakers with a 4 ohm transformer ??? the preferred set up is the 2 x 15" 8 ohm cab, but can I add another ( 1 x 15" tone ring cab), or will the degredation in sound/signal etc have a too large of an impact... or is it best not to use it ?? thanks

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StevenO

Joined: Sep 11, 2009
Posts: 61

Posted on Aug 09 2010 10:18 AM

I'm fairly certain the old transformers in vintage Fender amps can be run at +/- 100% difference in impedance. So 4 ohm into a 2 or 8 is OK, but not ideal, however 4 ohm into 16 ohm is not okay.

My single Showman is 4 ohm (stock, instead of the usual 8 ohm), which makes me believe it's an early Dual Showman with an older faceplate and it sounds great into a 4 ohm cab, but not so great into 8 ohm cab.

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LaFleur

Joined: May 20, 2009
Posts: 525
Leipzig
Germany

Posted on Aug 09 2010 11:27 AM

three 8 ohm speakers would be a way too much! If your amp is 4 ohm you would run it into calculated 2,6667 ohm, your amp will blow.

But if one cab is 8 ohm and the other one 8 ohm it will be calculated 4 ohm.
That would be an exact match!

—

http://www.reverbnation.com/bangmustang
http://www.facebook.com/bangmustang
https://soundcloud.com/bang-mustang

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dboomer

Joined: Jan 05, 2009
Posts: 262
Port Hueneme, CA
1 POTD Pin

Posted on Aug 09 2010 03:16 PM

LaFleur
My new amp has 4 ohms and the box 8ohm(meassured 5.4ohm)?
Does this work? What will happen technically?

Is your amp a tube model or solid state. If a tube amp it will make very little difference and it will change the tone a little (probably lose a few highs) and tube life a little. I wouldn't worry about it.

If solid state the 4 ohm rating on the amp would be the minimum impedance you should use. There will be a reduction of wattage if you plug an 8 ohm speaker as opposed to 4 ohms ... but no tone change (from the amp)

Your speaker measurement is DC resistance ... not impedance and 5 ohms or so would be normal.

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rotnroby

Joined: Mar 31, 2010
Posts: 877
Santa Barbara Ca... in the 805
1 POTD Pin

Posted on Aug 09 2010 08:41 PM

LaFleur
three 8 ohm speakers would be a way too much! If your amp is 4 ohm you would run it into calculated 2,6667 ohm, your amp will blow.

But if one cab is 8 ohm and the other one 8 ohm it will be calculated 4 ohm.
That would be an exact match!

hey did you find a Surfer tone ring cabinet?

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LaFleur

Joined: May 20, 2009
Posts: 525
Leipzig
Germany

Posted on Aug 10 2010 03:36 AM

No, its just an echolette tone-ring cab

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http://www.facebook.com/bangmustang
https://soundcloud.com/bang-mustang

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rotnroby

Joined: Mar 31, 2010
Posts: 877
Santa Barbara Ca... in the 805
1 POTD Pin

Posted on Aug 10 2010 07:47 PM

LaFleur
No, its just an echolette tone-ring cab

Ok, well if you win the lotto I still have the cabinet..

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TwangOmatic

Joined: May 16, 2008
Posts: 123

Posted on Aug 10 2010 10:44 PM

Tube amps don't like higher impedance loads and solid state is the opposite. It's better to short the terminals on a tube amp that to leave them unconnected.

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LaFleur Joined: May 20, 2009 Posts: 525 Leipzig	Posted on Jul 17 2010 04:48 AM My new amp has 4 ohms and the box 8ohm(meassured 5.4ohm)? Does this work? What will happen technically? — http://www.reverbnation.com/bangmustang http://www.facebook.com/bangmustang https://soundcloud.com/bang-mustang Top
Bilge_Rat Joined: Apr 20, 2009 Posts: 320 Toronto, Ontario Canada	Posted on Jul 17 2010 09:10 AM I wouldn't worry about it. — formerly SvD, bots.... member since 2006. Same game different name! Top
JeffH Joined: Apr 17, 2010 Posts: 97 PA	Posted on Jul 17 2010 08:09 PM Usually not a problem - what kind of amp? Although I don't gig, I run old Fender amps with mismatch both ways (4>8ohm, and 4>2 ohm) and haven't had any trouble. Running into a higher impedance cab is said to be easier on the tubes. I think if you're talking about a solid-state amp, it's a different story. Top
gawfshot Joined: Jul 03, 2010 Posts: 38	Posted on Jul 19 2010 11:42 PM "low into high, it will fly... high into low, it will blow" Top
bluez Joined: Jul 11, 2010 Posts: 135 Norway	Posted on Jul 20 2010 03:08 PM The reason why you are messuring 5,4 ohm is that you are messuring the DC resistance of the voice coil. 8 ohm is the average AC resistance from the resonase frequency of the speaker and usually up to the break up frequency. Top
SlacktoneDave Joined: Jul 01, 2006 Posts: 657	Posted on Jul 26 2010 08:12 AM gawfshot "low into high, it will fly... high into low, it will blow" A friend of mine took only 15 minutes to blow the 2 -ohm transformer in a mint brown Fender Concert Amp when he played it into a 16-ohm Marshall cabinet. He was probably pushing the amp pretty hard when that happened. I think amps sound better with properly matched speaker/amp combinations. Top
rotnroby Joined: Mar 31, 2010 Posts: 877 Santa Barbara Ca... in the 805	Posted on Jul 28 2010 02:36 PM SlacktoneDave gawfshot "low into high, it will fly... high into low, it will blow" A friend of mine took only 15 minutes to blow the 2 -ohm transformer in a mint brown Fender Concert Amp when he played it into a 16-ohm Marshall cabinet. He was probably pushing the amp pretty hard when that happened. I think amps sound better with properly matched speaker/amp combinations. I totally agree.. Never the less if your output Transformer is 4-ohms and your cabinet is rated @ 8-ohms you'll be fine however if your output transformer is rated @ 4-ohms and your running a 16-ohms cabinet your gonna heat up that transformer to were you just might do some damage... Good thing we all pay good attention to details.. Top
LaFleur Joined: May 20, 2009 Posts: 525 Leipzig	Posted on Aug 09 2010 08:35 AM I also connected another 8 ohm cab parallel to the Surfers Tone-Ring cab(so now its 4 ohm). Its really huge difference in sound!!! Its a lot louder and a way more dynamic than 4ohm amp into 8 ohm box. — http://www.reverbnation.com/bangmustang http://www.facebook.com/bangmustang https://soundcloud.com/bang-mustang Top
guitarslinger1 Joined: Oct 29, 2007 Posts: 185 Pacifica, CA	Posted on Aug 09 2010 09:26 AM Hi everyone, question ...can you use 3 8 ohm speakers with a 4 ohm transformer ??? the preferred set up is the 2 x 15" 8 ohm cab, but can I add another ( 1 x 15" tone ring cab), or will the degredation in sound/signal etc have a too large of an impact... or is it best not to use it ?? thanks Top
StevenO Joined: Sep 11, 2009 Posts: 61	Posted on Aug 09 2010 10:18 AM I'm fairly certain the old transformers in vintage Fender amps can be run at +/- 100% difference in impedance. So 4 ohm into a 2 or 8 is OK, but not ideal, however 4 ohm into 16 ohm is not okay. My single Showman is 4 ohm (stock, instead of the usual 8 ohm), which makes me believe it's an early Dual Showman with an older faceplate and it sounds great into a 4 ohm cab, but not so great into 8 ohm cab. Top
LaFleur Joined: May 20, 2009 Posts: 525 Leipzig	Posted on Aug 09 2010 11:27 AM three 8 ohm speakers would be a way too much! If your amp is 4 ohm you would run it into calculated 2,6667 ohm, your amp will blow. But if one cab is 8 ohm and the other one 8 ohm it will be calculated 4 ohm. That would be an exact match! — http://www.reverbnation.com/bangmustang http://www.facebook.com/bangmustang https://soundcloud.com/bang-mustang Top
dboomer Joined: Jan 05, 2009 Posts: 262 Port Hueneme, CA	Posted on Aug 09 2010 03:16 PM LaFleur My new amp has 4 ohms and the box 8ohm(meassured 5.4ohm)? Does this work? What will happen technically? Is your amp a tube model or solid state. If a tube amp it will make very little difference and it will change the tone a little (probably lose a few highs) and tube life a little. I wouldn't worry about it. If solid state the 4 ohm rating on the amp would be the minimum impedance you should use. There will be a reduction of wattage if you plug an 8 ohm speaker as opposed to 4 ohms ... but no tone change (from the amp) Your speaker measurement is DC resistance ... not impedance and 5 ohms or so would be normal. Top
rotnroby Joined: Mar 31, 2010 Posts: 877 Santa Barbara Ca... in the 805	Posted on Aug 09 2010 08:41 PM LaFleur three 8 ohm speakers would be a way too much! If your amp is 4 ohm you would run it into calculated 2,6667 ohm, your amp will blow. But if one cab is 8 ohm and the other one 8 ohm it will be calculated 4 ohm. That would be an exact match! hey did you find a Surfer tone ring cabinet? Top
LaFleur Joined: May 20, 2009 Posts: 525 Leipzig	Posted on Aug 10 2010 03:36 AM No, its just an echolette tone-ring cab — http://www.reverbnation.com/bangmustang http://www.facebook.com/bangmustang https://soundcloud.com/bang-mustang Top
rotnroby Joined: Mar 31, 2010 Posts: 877 Santa Barbara Ca... in the 805	Posted on Aug 10 2010 07:47 PM LaFleur No, its just an echolette tone-ring cab Ok, well if you win the lotto I still have the cabinet.. Top
TwangOmatic Joined: May 16, 2008 Posts: 123	Posted on Aug 10 2010 10:44 PM Tube amps don't like higher impedance loads and solid state is the opposite. It's better to short the terminals on a tube amp that to leave them unconnected. Top

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