Two NAD 2200 bridged amps w/6 ohm speakers - OK?
As shown on the last page of this datasheet the 2200 is rated to deliver considerable short-term power into a 4 ohm load (which would be seen as 2 ohms) when in bridged mode. It is not rated to deliver continuous power into a 4 ohm load when in bridged mode. So I suspect that at the low to moderate volume levels you referred to there would be no problem (the lower volume levels will mitigate the risk, to answer your question). But on the other hand, if you will not be listening at high volume why bridge? Just use one amp in stereo mode, particularly given that the amp has extremely high dynamic headroom (interpolating from the specs, probably about 500 watts of short-term power capability into the speaker's 6 ohm nominal impedance). Regarding your question about the fact that the speaker's impedance is higher than 6 ohms in much of the spectrum, what is most important is its impedance in the bass and mid-bass regions, since for most music those frequencies require the most power. The speaker does reach its minimum impedance within that part of the spectrum. Regards, -- Al |
I personally wouldnt recommend trying them out running 3ohms as my first thought is that you could possibly strain capacitors and run the life of them down signifigantly, but it sounds to me like a soustained high power 3ohm load that has to dip lower is like building a diesel truck up to 1000+ FT. LB. of torque and not installing a new transmission or torque converter IE. it blows the tranny quick, it will handle it for a bit but it wont do it for more than 20% of its standard life. I dont know that this is true with amplifiers but it seems more logical to upgrade to a stereo amp as it allows you more flexibility in impedence dips and with speaker choices. Also Believe it or not Speaker modification is possibly an option. I have had my celestions upgraded years ago with all new capacitors, internal wire, and binding posts for a very reasonable price. If you are in the SF BAY look up Soundscape AV in santa rosa and ask for there tech. |
I never tried using the 2200 bridged when I had a pair but from the manual. Note: in the bridged mode the loudspeakers impedance is effectively halved as seen by the amplifier. An 8-ohm load looks like 4-ohms, a 4-ohm load looks like 2-ohm, and a pair of 4-ohm speakers operated in parallel will look like a 1-ohm load. Driving paralleled low-impedance speakers to high levels may cause the amplifier to overheat and shut down, or cause internal fuses to blow in order to protect the amplifier. For best results the bridging mode should be used with a single 4-ohm or 8-ohm speaker in each channel. If you try it start with a low volume and feel how hot they get. Most of the NAD manuals can be found here: NAD Regards, Todd |
