# Bridging an Amp



## Danny (May 3, 2006)

I have a Ramsa Amp that will put out 400Watt/Ch at 4 Ohm, however my sub requires 
600Watt and the Ramsa will only put out 800Watt into 8 Ohm (it's a 4 ohm Sub), would it be fine to bridge it but only run it at about 3/4 power, - I'd have to lower the input level as it doesn't have an attenuation control on the amp


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## F1 fan (Jul 6, 2006)

I am not familiar with your amp(is it an Australian make?) but does it have a switch to put it into bridged mode?
Did you by chance mean to say the sub will handle 600 watts not needs 600watts?400 watts should be plenty unless it is very ineficient.

Also is the 800 watt into 8ohm's figure you mention for bridged operation?If Ramsa make no mention of a 4ohm bridged output capability than it might indicate that they do not recommend driving a 4 ohm load when bridged. 
Generally when amps are bridged they dont like to see 4 ohm and lower impedances but you could always give it a try.


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## Danny (May 3, 2006)

It has a bridging switch, the sub can handle 600Watts so I really want to put as much as possible through so I get some loud bass, 99Db/W/M sensitivity.Amp is an Australian Model - made by Panasonic. Just wondering if running it at less than the max output bridged figure (ie 600Watt instead of 800) would increse its reliability at 4 ohm


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## eddthompson (Aug 19, 2006)

im not sure bridgeing it will be a good idea, you could try of course, at the levels you will be running at in your home it may not draw enough current to be an issue, but as already said, i doubt there will be an improvement over the 400watts your already using.

to put it another way, going from 400 to 600 watts will probably only give you a couple of decibels in extra volume, especialy at low frequencies. (i think im right in saying double the power gives you 3db in extra volume)

edd


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## Wayne A. Pflughaupt (Apr 13, 2006)

> I am not familiar with your amp(is it an Australian make?)


Ramsa is Panasonic’s line of pro audio products.

Generally, it’s not a good idea to run an amp at 4 ohms bridged unless it carries a rating of 2-ohms in stereo. That said, you might be able to fudge that since you aren’t using the amp for the demanding pro applications it was designed for. But, any amp bridged is not as stable as unbridged, so you can’t entirely eliminate the risk.

Have you tried it yet in stereo mode? As long as you get all the output from your sub that your room needs, all those power specs don’t matter. IOW, you might not even need the 800 watts your sub is rated for.

Regards,
Wayne


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## F1 fan (Jul 6, 2006)

Wayne A. Pflughaupt said:


> Ramsa is Panasonic’s line of pro audio products.


I have not heard of Ramsa before did it replace the Technics name? Hav'nt seen any products with this name in a while either.

Danny, If your woofer is rated at 99db/1w/1m than 400 watts should be more than enough.


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## Wayne A. Pflughaupt (Apr 13, 2006)

The Ramsa line dates to at least late 80s - which is about where my pro audio experience begins, so it may well go back even further. So yes, the brand was concurrent with the Technics name. There is still an official Ramsa website, although the product line seems significantly scaled back from days past (they used to make some huge, awesome  mixing consoles, for instance). Their amps were well regarded in pro circles back in the day, don’t know how they are now. However, they were and still are some of the coolest-looking around! (They didn’t have the Panasonic logo back when.)












By the way, as far as I can see, the only product associated with the Technics brand anymore is a professional-grade turntable.

Regards,
Wayne


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## F1 fan (Jul 6, 2006)

Thanks for the info Wayne. Is your pro expierience in studio or PA?


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