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Amplifier specified 4 Ohm into 2 Ohm?

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serioussound View Drop Down
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    Posted: 27 March 2018 at 8:13pm
I have some amplifiers RCF http://www.rcf.it/en_US/products/commercial-audio/amplifiers-and-preamplifiers/am-1122-n

They have single mono 4 ohm output. How bad is it to wire for example 2 pcs RCF MR 55 on these which would make 2 Ohm?

I want to have 2 cabs on each amplifier and the speakers are 4 Ohm.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 27 March 2018 at 8:51pm
If they're only rated to 4 Ohm, running them at 2 Ohm is a Very Bad Idea. If it could safely drive a 2 Ohm load, it would be rated at 2 Ohm. Many amps rated 2 Ohm even struggle to drive a 2 Ohm load. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote serioussound Quote  Post ReplyReply Direct Link To This Post Posted: 27 March 2018 at 8:54pm
how common is is to serial the speakers so the 2 pcs 4 ohm cabs makes 8 ohms?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 27 March 2018 at 10:41pm
Happens all the time. No problems there.
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serioussound View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote serioussound Quote  Post ReplyReply Direct Link To This Post Posted: 27 March 2018 at 10:45pm
Ok because I would do the serial connection outside the cab thats no problem?

Easisest way having a single wire cable to each speaker from amplifier and then a dual wire in between speakers?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 27 March 2018 at 11:04pm
Originally posted by serioussound serioussound wrote:

Easisest way having a single wire cable to each speaker from amplifier and then a dual wire in between speakers?
No, single wire in between speakers.




Edited by Conanski - 27 March 2018 at 11:06pm
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serioussound View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote serioussound Quote  Post ReplyReply Direct Link To This Post Posted: 27 March 2018 at 11:07pm
Yes sorry my mistake..

Easiest is to split a dual standard speakercable I guess?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote knet94 Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2018 at 7:29pm
I have noticed that the recommended power requirement for these speakers is 175 watts. The amps are only rated at 120 watts in 4r so significantly under-powered already. Wiring in series to get 8r will reduce the output of the amp by up to half, so potentially 60 watts output or 30 watts to each speaker which require 175 watts to give their full potential. This is not exactly ideal and i would recommend you only do this as a very temporary solution.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote serioussound Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2018 at 8:15pm
I also have the rcf mr 44 which is much less in watts ...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JonB67 Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2018 at 10:51pm
Could get another amp big enough to run the comfortably at 8ohms?

Old amps are cheap if you don't mind the weight.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote serioussound Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2018 at 10:53pm
Its just I have many of these RCFs laying around.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 29 March 2018 at 12:50am
If you want to run 2 cabs on each amp in bridge mode and they're only seeing 30w amp power each, you could do a lot better by just selling these RCF amps on eBay (where they should fetch more than their watt rating alone would warrant due to 100v line and other features (are any of these critical to you?) and spend whatever you get on a couple of used ~300-1000wpc amps. Even if you need the signal to be split for processing purposes you could pick up 3x 300-400wpc amps and run 2 speakers on each channel.


Edited by Hemisphere - 29 March 2018 at 12:51am
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