running amp below rated impedence

I have a Rockford Fosgate T5002 2 channel and 6 8ohm speakers that I want to run off of it. The Rockford is rated 1000+ bridged 2ohm and I'm trying to keep from have to get another Rockford Amp for 2 speakers. So I was wondering the risks of running the amp at a bridged 1.33ohms. and I want to atleast know that that the 100amp fuse will blow if the amp is being driven too hard. I plan on setting the gains as I always have which is by the example given on this forum.

Thanks

Adam

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I can't hear you!

I would not attempt that. If it were my amp and it blew up, I could fix it myself, and I still wouldn't try it. When they break they break big.  No the fuse may not protect the amp.  A 2.666 ohm stereo load will be your safest bet.

i am an idiot wrote:

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I would not attempt that. If it were my amp and it blew up, I could fix it myself, and I still wouldn't try it. When they break they break big.  No the fuse may not protect the amp.  A 2.666 ohm stereo load will be your safest bet.

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Can I get 2.66 with 6 speakers?

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I can't hear you!

Wire three pairs of 8-ohm drivers in series, for 16 ohms.

Wire those three pairs of speakers in parallel for 5.33 ohms.

When bridged, the amplifier will be perfectly safe, and seeing an effective load of just over 2.6 ohms per channel.

It'll be exactly the same amount of power as running the amp with three woofers in parallel per channel.

One last point... and it's not directly specifically at YOU, but seriously, when are people going to realize that Rockford Fosbreak amplifiers have some of the most shoddily designed power supplies out there? They have little to zero additional current capacity... They'll fry if you LOOK at 'em crooked... DO NOT attempt to run that amp below 2-ohms bridged! You've now been warned twice! As i am an idiot has told you: when they break, they break BIG! The best you'll be able to do is 2.67 ohms per channel, either in stereo mode with three per channel, or series-parallel wired and bridged into 5.3 ohms.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

haemphyst wrote:

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Wire three pairs of 8-ohm drivers in series, for 16 ohms.

Wire those three pairs of speakers in parallel for 5.33 ohms.

When bridged, the amplifier will be perfectly safe, and seeing an effective load of just over 2.6 ohms per channel.

It'll be exactly the same amount of power as running the amp with three woofers in parallel per channel.

One last point... and it's not directly specifically at YOU, but seriously, when are people going to realize that Rockford Fosbreak amplifiers have some of the most shoddily designed power supplies out there? They have little to zero additional current capacity... They'll fry if you LOOK at 'em crooked... DO NOT attempt to run that amp below 2-ohms bridged! You've now been warned twice! As i am an idiot has told you: when they break, they break BIG! The best you'll be able to do is 2.67 ohms per channel, either in stereo mode with three per channel, or series-parallel wired and bridged into 5.3 ohms.

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Yeah ive had enough of rockfords go bad on me thats why i was sure to ask the risks before RISKING it..

SO i see that you say it'll be a 5.3 ohm load but the amp will see a 2.67ohm load bridged. So will my DMM read 5.3ohms at the amps speaker terminals? even if the amp is seeing a 2.67ohm load? I just like to check all my loads before turning things back on to make sure wires arent screwed up. Thanks

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I can't hear you!

Yep.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

haemphyst wrote:

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Yep.

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Sorry I thought you were gonna go more into depth of why that is. Is it because it is in connected series-parallel? and how does that happen?

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I can't hear you!

rfhvhtoo wrote:

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Sorry I thought you were gonna go more into depth of why that is. Is it because it is in connected series-parallel? and how does that happen?

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Yes. Series parallel for six 8-ohm woofers nets a 5.3-ohm final impedance.

haemphyst wrote:

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Wire three pairs of 8-ohm drivers in series, for 16 ohms.

Wire those three pairs of speakers in parallel for 5.33 ohms.

When bridged, the amplifier will be perfectly safe, and seeing an effective load of just over 2.6 ohms per channel.

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This is the same reason a 4-ohm load causes an amplifier to make it's 2-ohm load power in bridged mode. The amplifier "sees" 2-ohms per channel in bridged mode, even though the load connected is 4-ohms. It's all about voltage and current.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

alright yeah i got you. The amp is putting out the power of each channel being at 2 ohms. The problem is that its capable of 1 ohm each channel and im trying to get a bit more out of it but thanks alot and I doubt ill push it beyond any limits.

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I can't hear you!

rfhvhtoo wrote:

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Can I get 2.66 with 6 speakers?

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You can get a 2.66 ohm STEREO load with 6 speakers.  Parallel 3 speakers per channel.  The amp will do the same exact power in that configuration as it will in the config that Haem suggested.  However if you series speakers, the amp loses the ability to properly control the speaker. 

i am an idiot wrote:

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rfhvhtoo wrote:

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Can I get 2.66 with 6 speakers?

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You can get a 2.66 ohm STEREO load with 6 speakers.  Parallel 3 speakers per channel.  The amp will do the same exact power in that configuration as it will in the config that Haem suggested.  However if you series speakers, the amp loses the ability to properly control the speaker.

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If there is more than two drivers wired in series, THEN I would be worried about the control issue... Otherwise... nope...

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."