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Running Benchmark AHB2 in bridged mode and 4 Ohm Speaker

Does running this amp in bridge mode mean each channel will see half the impedance i.e 2 Ohm each when connected to a 4 Ohm speaker.  If so will this cause a problem when the speaker dips to 3 or 2 ohms?. 

Anyone running Benchmark AHB2 in bridged mode with low impedance speakers?. 
geek101
jon_5912
605 posts
 
You can't double voltage without also doubling current.  volts = current times resistance.  29 amps into 8 ohm speakers would be 6,728 watts.  That is instantaneous and not remotely sustainable, obviously.  Actual sustainable current is directly related to watts.  More watts means more voltage and more current flowing.
kijanki's avatar
kijanki
4,428 posts
 
jon_5912, Yes, current will double when you double voltage, but you stated that current CAPABILITY (meaning max current) will be better. Current capability of AHB2 in bridged mode will be still 29A.

Assuming that you meant current (and not current capability) at given volume, it should state "at given volume knob position".  At given volume (meaning loudness) bridged and unbridged configuration currents will be the same.
jon_5912
605 posts
 
Max current will double.  If an amp can double the voltage into a load by bridging then the current capability also doubles.  I'm not sure what the max current rating really means.  29 amps into 8 ohms requires 232 volts.  I'm pretty sure that isn't possible.  Maybe it's theoretical short circuit current or something.  
kijanki's avatar
kijanki
4,428 posts
 
Maximum current won't double.  (It will be still 29A).    Maximum current is an absolute maximum that amplifier can deliver.  This specification shows amplifier's ability to drive difficult low impedance loads.  It says that when 4 ohm speaker's impedance drops to 1 ohm amp can deliver 29V peak.

Also, I'm not sure where specification 480W/4ohm came from.  My manual (version G), as well as their website, shows 480W/6ohm bridged and 130W/6ohm unbridged.  480W is not that far from theoretical 530W for ideal voltage source.
jon_5912
605 posts
 
The maximum current that can be delivered into 8 ohms or any other load will double when the voltage doubles.  I obviously wasn't talking about the 29 amp "Maximum Audio Output Current" as specified by the benchmark website.  We were discussing current capability into varying typical speaker loads.  The maximum continuous current capability into 8, 4, whatever loads will increase when an amp is bridged.  
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