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11-02-2010, 08:16 PM
| | Registered User | | Join Date: Oct 2003 Location: Tasmania, Australia. | | | What are the concerns of running a 4ohm bass head into a single 8 ohm 4x10?
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I dont quite understand. Looking at picking up a cheap Peavey T Max. 350 watts at 4ohms, 500 watts at 2 ohms but I only have 8 ohm cabs.
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Ashdown EVO III 500. Ashdown ABM 410 cabs. Metal Bassist member 65.
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11-02-2010, 08:18 PM
| | | | thats fine, you just wont get the full power, 2 8 ohm cabs will be running the amp and 4 ohms and 3 8 ohm cabs will bring it down to 2 ohms.
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11-02-2010, 08:20 PM
|  | THIS HAND OF MINE GLOWS WITH AN AWESOME POWER! | | Join Date: Sep 2007 Location: USA; Mitchellville, Maryland | | | Cabs, plural? Run 'em together! There's no real concern except the wattage limitations. You might not be able to crank the head as much as you would with a 4 ohm load. Some people say that running at 8 ohms chokes the tone of the bass but I don't think there's any scientific basis for that and I haven't heard any significant difference if at all. Supposedly you'll be able to get louder with a 4 ohm load as well but according to some smart folks on TB the volume difference would be marginal.
__________________ Source Audio Sourcerer #22 Club Clement #73 Markbass Club #231 Quote:
Originally Posted by geeza  I thought your name was one of those "it's spelled 'Kwesi', but it's pronounced 'Craig'." kind of names. | Me: Youtube, Flickr |
11-02-2010, 08:20 PM
| | Registered User | | Join Date: Jan 2002 Location: Palm Coast, Florida | | Quote:
Originally Posted by Govier966 thats fine, you just wont get the full power, 2 8 ohm cabs will be running the amp and 4 ohms and 3 8 ohm cabs will bring it down to 2 ohms. | Minor correction................
Two 8 ohm cabs = 4 ohms
Three 8 ohm cabs = 2.67 ohms
Four 8 ohm cabs = 2 ohms
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11-02-2010, 08:21 PM
|  | www.HeavyMetalOpera.com
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You have no worries since it's a solid state amp... |
11-02-2010, 08:32 PM
| | Registered User | | Join Date: Oct 2003 Location: Tasmania, Australia. | | | Thanks guys - and a minor correction on my behalf. I understand how to calculate impedance, just thought that the amp might damage the speakers, although I cant say what I was basing this on. This is the part I didn't understand but got it now.
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Ashdown EVO III 500. Ashdown ABM 410 cabs. Metal Bassist member 65.
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11-02-2010, 08:38 PM
| | THIS HAND OF MINE GLOWS WITH AN AWESOME POWER! | | Join Date: Sep 2007 Location: USA; Mitchellville, Maryland | | | It can damage the speaker if you run the thing at 11. But as long as you aren't hearing any farting out or distortion you should be safe though.
__________________ Source Audio Sourcerer #22 Club Clement #73 Markbass Club #231 Quote:
Originally Posted by geeza I thought your name was one of those "it's spelled 'Kwesi', but it's pronounced 'Craig'." kind of names. | Me: Youtube, Flickr |
11-03-2010, 06:55 AM
| | Registered User
Owner, Bill Fitzmaurice Loudspeaker Design | | Join Date: Sep 2004 Location: New Hampshire | | Quote: |
What are the concerns of running a 4ohm bass head into a single 8 ohm 4x10?
| There are none. |
11-03-2010, 05:47 PM
| | Registered User | | Join Date: Oct 2003 Location: Tasmania, Australia. | | | I love Talkbass. Thankyou all.
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Ashdown EVO III 500. Ashdown ABM 410 cabs. Metal Bassist member 65.
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11-04-2010, 01:44 AM
| | Registered User | | Join Date: Feb 2005 Location: Johannesburg, South Africa | | Quote:
Originally Posted by billfitzmaurice There are none. | +1  |
11-04-2010, 10:31 PM
|  | Registered User | | | | | For future reference (From Carvin)
SPEAKER COMBINATIONS and OHMS ( Ω ):
Four x 8Ω cabinets = 2Ω
Three x 8Ω = 2.66Ω
Two x 8Ω = 4Ω
Two x 4Ω = 2Ω
One 8Ω and One 4Ω cabinet = 2.66Ω
Two 8Ω and One 4Ω = 2Ω
One 2.66Ω and One 8Ω = 2Ω
Two x 2Ω = 1Ω
Three x 4Ω = 1.33Ω
Two x 4Ω and One 8Ω = 1.6Ω
One 2.66Ω and One 4Ω = 1.6Ω
Mike |
11-04-2010, 10:36 PM
| | www.HeavyMetalOpera.com
Unofficialy endorsing EBMM, Avatar Speakers | | Join Date: Feb 2002 Location: Seattle (ish), WA | | Quote:
Originally Posted by keyboardguy For future reference (From Carvin)
SPEAKER COMBINATIONS and OHMS ( Ω ):
Four x 8Ω cabinets = 2Ω
Three x 8Ω = 2.66Ω
Two x 8Ω = 4Ω
Two x 4Ω = 2Ω
One 8Ω and One 4Ω cabinet = 2.66Ω
Two 8Ω and One 4Ω = 2Ω
One 2.66Ω and One 8Ω = 2Ω
Two x 2Ω = 1Ω
Three x 4Ω = 1.33Ω
Two x 4Ω and One 8Ω = 1.6Ω
One 2.66Ω and One 4Ω = 1.6Ω
Mike | This assumes parallel wiring only. |
11-04-2010, 11:19 PM
|  | Registered User | | Join Date: Jan 2007 Location: SF (North) Bay Area | | Quote:
Originally Posted by billfitzmaurice There are none. | This... the master has spoken. |
11-04-2010, 11:35 PM
| | Registered User | | Join Date: May 2009 Location: Surrey, B.C. Canada | | | would 2.66 be bad for a 2ohm head?
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11-04-2010, 11:44 PM
| | Registered User | | Join Date: Apr 2010 Location: O'Fallon, IL | | Quote:
Originally Posted by loopee would 2.66 be bad for a 2ohm head? | No. Read the posts above yours.
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11-05-2010, 12:37 AM
| | Registered User | | Join Date: Oct 2003 Location: Tasmania, Australia. | | Quote:
Originally Posted by loopee would 2.66 be bad for a 2ohm head? | My understanding is if the head has a minimum impedence of 2ohms then anything equal greater than this is fine.
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Ashdown EVO III 500. Ashdown ABM 410 cabs. Metal Bassist member 65.
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11-05-2010, 12:47 AM
|  | Registered User
Endorsing artist:see profile/Current Setup | | Join Date: Jan 2002 Location: CHICAGO,IL. | | Quote:
Originally Posted by jcburn I dont quite understand. Looking at picking up a cheap Peavey T Max. 350 watts at 4ohms, 500 watts at 2 ohms but I only have 8 ohm cabs. | If you have an amp that runs 350 watts at 4 ohms and you run it into a single 8 ohm cab, you will not get the full 350 watts. |
11-05-2010, 07:03 AM
| | Registered User
Proprietor Springvale Studios | | Join Date: May 2008 Location: Ipswich UK | |  Well!
Quote:
Originally Posted by jcburn I dont quite understand. Looking at picking up a cheap Peavey T Max. 350 watts at 4ohms, 500 watts at 2 ohms but I only have 8 ohm cabs. | Your 8 ohm cab is in fact a cunningly disguised 2 ohm cab
all you need to do is rewire it all drivers in parallel.
The crossover for the tweeter is probably just a simple high pass only, does it have a level control.
So how much are you going to pay me for all this knowledge to get you from a 175 watt bass rig to a 500 watt rig.  |
11-05-2010, 07:10 AM
|  | bassist for staind | | | | Quote:
Originally Posted by billfitzmaurice There are none. | the concern is that you wont get full power from the amp. i would consider that a concern. someone had pointed it out already, but 150w may not be enough. i hope it is. johnny a / staind |
11-05-2010, 07:16 AM
| | Registered User
Owner, Bill Fitzmaurice Loudspeaker Design | | Join Date: Sep 2004 Location: New Hampshire | | Quote:
Originally Posted by staindbass the concern is that you wont get full power from the amp. | 99% of the time a cab can't make use of more than half its rated power anyway, if that much, so 'getting the full watts' is seldom a concern. | | Thread Tools | Search this Thread | | | | 
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