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Old 17th December 2007, 07:41 AM   #1
95Honda is offline 95Honda  Germany
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Default Lower rails for lower impedance?

I have a pair of Acurus A250s. I also have a pair of dual 2 ohm subwoofers I would like to power. Does anyone know if dropping the rail voltage 20% or so would make operation into a nominal 2 ohm load possible with an amplifier like this? I have plenty of tansformers to play with. I haven't looked inside the amps in a while, but IIRC, the power tranny only had one set of secondaries and one set of rails, the amplifier modules only had one set of +/- DC voltage inputs... No seperate windings/supplies for the front end, etc....

I have no idea what kind of protection the amps have either....

I am currently running one of the amps for both subs, 4 ohms per channel. I would like to make use of the second amplifier, it is doing nothing right now and the added output would be nice....
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Old 17th December 2007, 12:29 PM   #2
AndrewT is offline AndrewT  Scotland
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Hi,
is dual 2ohm a DualVoiceCoil?
Then connecting the VC in series is 4ohm load.
A pair can be connected in series or in parallel giving either 8ohm or 2ohm loads.
Alternatively power each DVC as a 4ohm ohm load from each amplifier.
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Old 17th December 2007, 06:02 PM   #3
95Honda is offline 95Honda  Germany
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With dual 2 ohm coils for a pair of subs you can only end up with a pair of 4 ohm subs, or a pair of 1 ohm subs, or a single 8 ohm load, either way, this only works for 1 amplifier, not the pair. I am currently running the one amp on both subs, 4 ohms per side. I could run both amps, just using one channel of each (kind of a waste), or just run each amp at 2 ohms stereo on a single sub (bad idea)

I want to run both amps.... and use the full 800 watts from each amp...

I made a big step back in power, I got rid of the 2.8Kw PA amps I was running before, one running each sub. They had a lot of headroom, but the fans drove me nuts. The A250 sounds a hell of a lot better than the Peavey amps, but I lost some of the headroom I had.

The subs are a pair of XXX 18s, BTW, the XBL2 versions, in big vented boxes tuned really low, but they can still use a little more than 400 watts each, I think 800 would be better....
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Old 18th December 2007, 08:31 AM   #4
95Honda is offline 95Honda  Germany
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I think I may just re-cone with dual 4 ohm coils...... This may give me more flexiblity in the future anyway..... I was pretty hung up on shear power when I had these subs built with dual 2 ohm coils originally...
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Old 18th December 2007, 03:12 PM   #5
taj is offline taj
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Hi 95Honda,

Why use DVC if you re-cone? These are more versatile to the stores selling them than someone building a permanent solution. Why not just use the impedance you need.

The power you draw with lower impedance loads comes with a price tag and isn't necessarily louder. Higher distortion, and generally speaking, less power efficient driver construction. It's a trade-off I've never favoured myself.


..Todd
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Old 18th December 2007, 04:53 PM   #6
95Honda is offline 95Honda  Germany
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I don't really understand your post.... I think I am misunderstanding something...

I am going to switch to dual 4 ohm coils from dual 2 in order to make better use of the home audio oriented amplifiers out there today.... This gives me the option to have dual 4 ohm loads per sub or a single 8 ohm, or single 2 ohm if I ever decide to go back to a prosound amp... My whole point with the recone was to have a higher impedance driver and stay away from the real low impedance high current amplifiers avalible... That I have used before...
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Old 19th December 2007, 07:57 AM   #7
AndrewT is offline AndrewT  Scotland
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Why bother reconing when you already have a 4ohm driver.
just buy, or use, an amplifier that can properly drive a real 4ohm reactive load.
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Old 19th December 2007, 08:59 AM   #8
95Honda is offline 95Honda  Germany
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I have a pair of amplifiers that are 4 ohm stable. I have a pair of subwoofers that have dual 2 ohm coils. I would like to use my pair of amplifiers on my pair of subwoofers. I cannot do this because my pair of amplifiers cannot drive my pair of subwoofers using all of the avalible power (channels) due to my voice coils being dual 2 ohm. If they were dual 4 ohm coils I could use both amplifiers, one on each sub, each driving a pair of 4 ohm coils, each putting out a full 800 watts per subwoofer.

This is my problem... Unless I upgrade/change something...
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