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MC2 E45 amp ability to power 2 ohm circuit

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Category: General
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Forum Description: The 'Stopping Jake Fielder moaning constantly' forum description...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=105929
Printed Date: 29 September 2022 at 5:03am
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Topic: MC2 E45 amp ability to power 2 ohm circuit
Posted By: Lillike_natnek
Subject: MC2 E45 amp ability to power 2 ohm circuit
Date Posted: 10 December 2020 at 10:08am
Hi all,

Yesterday I also made a post in the scoop forum for driver recommendations where we're deciding to go for 2x 8ohm or 2x 4ohm drivers for our hog scoops (so resistance of circuit becomes 2 or 4 ohm respectively). The amp that we will use is the MC2 E45, which according to the spec sheet should be able to power a 2ohm circuit with a max output power of 4200W. Now this seems more appealing than a 4ohm circuit which has a max power output of 2500W. 

Many times I read that 2 ohm is not good for the amp etc. but can anyone explain why this is? If the spec sheet says the amp supports 2 ohm circuits, then what would hold us back from utilising that? I've been reading up on it but I can't really find a definitive explanation. We've been discussing this topic with the people of our soundsystem but we don't really know what to do (we don't have a lot of experience). If anyone could shine a light on this that would be really helpful!

Cheers



Replies:
Posted By: Sinai Sound
Date Posted: 10 December 2020 at 10:17am
2ohm playing aggressively loud 40hz?

or 2ohm playing 10khz at low volume ... 

Both are quite a different load on an amplifier, but both are "2ohm"

(also before the nerds get at me, that's 2ohm nominal, very much aware it changes with frequency etc etc )


Posted By: Lillike_natnek
Date Posted: 10 December 2020 at 10:23am
Guess leaning more towards the former, as it should handle the power of two hog scoops at max volume (I'd say 35 - 80/100Hz)


Posted By: smitske96
Date Posted: 10 December 2020 at 10:35am
Being on this forum for several years, I learned one thing.
There is definately a different understanding in sound when it comes to different music genres.
Personally I would not bother about the last 2dB (its a very small difference).
If you really want that extra, you would be better of with more cabs imho.

What kind of music is it actually?

And yes, the E45 could handle 2 Ohm loads (with the test conditions specified in the manual), however, I would not run it that way for different reasons like durability etc. Heavy 2 Ohm load will require more current which then results in more heat. 


PS: if you're after a transformer amp, I have a Infinite 7v2 for sale. Not a 8v2 but it can do for some occasions.


Posted By: cravings
Date Posted: 10 December 2020 at 10:38am
if your car is sold as being capable of 150mph, you probably shouldn't drive it at that speed all the time.. cos it'll start to wear out.


Posted By: Earplug
Date Posted: 10 December 2020 at 10:41am
Driving the amp at 2 ohms will shorten it's life by years. And as hinted above, any gain you think you are getting is destroyed by power compression.

Stick to 8 ohm drivers - and you could then, at some point, add another cab per side without over-stressing the amp - which is far better. 




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Earplugs Are For Wimps!


Posted By: Sinai Sound
Date Posted: 10 December 2020 at 10:49am
Powersoft K10 / K20 will do this. Ran it like this in anger many many times until upgrading to X8. 

Void Inf8 v2 will do it on a decent supply (seen peaks of 40a on the front doing what you're asking, "2ohm" load per side), but also probably pop fuses internally, again seen it happen.





Posted By: Sinai Sound
Date Posted: 10 December 2020 at 10:52am
This was a 4 x 8ohm drivers per side (so 2ohm nominal), running the frequency you want to play, at loud volumes





Posted By: Lillike_natnek
Date Posted: 10 December 2020 at 11:06am
Originally posted by smitske96 smitske96 wrote:

What kind of music is it actually?

And yes, the E45 could handle 2 Ohm loads (with the test conditions specified in the manual), however, I would not run it that way for different reasons like durability etc. Heavy 2 Ohm load will require more current which then results in more heat. 

PS: if you're after a transformer amp, I have a Infinite 7v2 for sale. Not a 8v2 but it can do for some occasions.

Mixed genres basically, mostly dub/dnb/techno I'd say.

Could you explain what a transformer could mean for us in this scenario?


Originally posted by cravings cravings wrote:

if your car is sold as being capable of 150mph, you probably shouldn't drive it at that speed all the time.. cos it'll start to wear out.

That makes sense LOL


Originally posted by Earplug Earplug wrote:

Driving the amp at 2 ohms will shorten it's life by years. And as hinted above, any gain you think you are getting is destroyed by power compression. 

Stick to 8 ohm drivers - and you could then, at some point, add another cab per side without over-stressing the amp - which is far better.  

Yeah that sounds like a solid plan for the future. But then for future expansion we could also have gone for 2x 4Ohm drivers per channel instead of 2x 8 ohm drivers. But reading all the other comments I guess we should waive that idea. It just sounded attractive as the output power is higher but I'm starting to understand that this is just bad for the amp.


Originally posted by Sinai Sound Sinai Sound wrote:

Powersoft K10 / K20 will do this. Ran it like this in anger many many times until upgrading to X8.


I'm afraid that's a bit out of our budget haha. I guess moral of the story is that we should not go for a 2ohm nominal circuit. Did your void amps survive that current? 



Posted By: smitske96
Date Posted: 10 December 2020 at 11:21am
Do you already have the hog and the other cabs? If no, I would advise you to look at the latest paraflex options. More and more designs are getting tested, and look really promising. Btw they also have various kick designs if needed.


Posted By: Lillike_natnek
Date Posted: 10 December 2020 at 11:27am
Originally posted by smitske96 smitske96 wrote:

Do you already have the hog and the other cabs? If no, I would advise you to look at the latest paraflex options. More and more designs are getting tested, and look really promising. Btw they also have various kick designs if needed.

Yes we've got all cabs already. Only need to put drivers in our hogs, the rest is all done. Never heard/read about paraflex cabinets yet, got some links to read up about?


Posted By: smitske96
Date Posted: 10 December 2020 at 12:08pm
There is a whole dedicated forum on fb (if you have fb). 
I can send you the link if you want.


Posted By: Earplug
Date Posted: 10 December 2020 at 1:05pm
" It just sounded attractive as the output power is higher"

Yes - it can be difficult to understand that more power might actually not lead to more SPL. Far better to add square inches (or centimeters) of cone!   Smile




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Earplugs Are For Wimps!


Posted By: kipman725
Date Posted: 10 December 2020 at 2:03pm
When you look at the full spec sheet you can see that this amp should be able to deal with 2 ohm load as the power output per channel has only reduced to 4100W even with a crest factor of only 2.8.
https://www.mc2-audio.co.uk/wp-content/uploads/e45_datasheet.pdf" rel="nofollow - https://www.mc2-audio.co.uk/wp-content/uploads/e45_datasheet.pdf
https://www.mc2-audio.co.uk/wp-content/uploads/mc2_amp_power_measurement.pdf" rel="nofollow - https://www.mc2-audio.co.uk/wp-content/uploads/mc2_amp_power_measurement.pdf

The choice of whether to run at 2ohms then comes down to how important maximizing the service life of the amp is for you compared to getting the most possible output power out of the amp.  The amplifier is rated for it but your still doubling the current in the output transistors and running parts hotter.  You could always run 6*8ohm drivers off each amp for 2.67 ohm per channel as a compromise.

To bother with 4ohm drivers to me is more about the driver than the amp, if its a super high performance 21" driver with a 6" coil you might want to consider 4ohm just to get the most out of the driver but if its just an average 18" 4" coil driver then the driver will already be thermally compressing and there will not be much gain by the potential doubled power on the voice coil (apart from a cooked driver).



Posted By: levyte357-
Date Posted: 04 May 2022 at 10:58am
Originally posted by Sinai Sound Sinai Sound wrote:

This was a 4 x 8ohm drivers per side (so 2ohm nominal), running the frequency you want to play, at loud volumes





One of the rare moments, Speakerplans Amp Forum, brings a smile to your face. LOL

EDIT : Would be very skeptical about MC2 E45, having the nuts, to pull 35A off the mains, even though it has higher rated output, at 2 ohms, than Inf 8 MK2..

Hmmm...


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Global Depopulation - Alive and Killing.


Posted By: csg
Date Posted: 04 May 2022 at 12:46pm
Correct, the infinite 8 MK2 is a far superior arc welder.

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“The fact is this is about identifying what we do best and finding more ways of doing less of it better”


Posted By: levyte357-
Date Posted: 04 May 2022 at 1:25pm
Originally posted by csg csg wrote:

Correct, the infinite 8 MK2 is a far superior arc welder.


Are you saying the MC2 E45 is a fantastic beast, that can produce power, without sucking current from the wall !?


I've "PERSONALLY" seen Powersoft K20, suck 34.9A from the wall, while powering 4x 8 ohm subs, so that amp is exempt from this type of argument, forever !!!

LOL


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Global Depopulation - Alive and Killing.


Posted By: csg
Date Posted: 04 May 2022 at 5:05pm
Quite the reverse. The E45 will play music just fine. Want to rinse every last dB out of your dynamic range? Stick with the void.

Why anyone is interested in balls out performance into 2R both channels sub is beyond me. Power is cheap these days, go with something with plenty of voltage and keep to 8R. 


-------------
“The fact is this is about identifying what we do best and finding more ways of doing less of it better”


Posted By: al_x
Date Posted: 04 May 2022 at 6:40pm
I recently borrowed a friends E45 to power two B&C 18ds115 on sub. It managed 6 hours in a hot room, 4ohm bridge on a 13a plug quite happily (playing drum and bass and jungle so a lot of long sustained bass notes)



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