Amps rated for 8 ohms BRIDGED for 4 ohm SVS? (1 Viewer)

[ColinM]

I'm thinking seriously about EQ'ing my SVS, and I'll be pushing the limits of my NHT SA-2. I love that amp as it is, but I find myself looking at eBay for something in the 200-300 watt mono range into 4 ohms. My options would expand immensely if I could include 8 ohm bridged amps in my search.

It seems plausible that since the sub operates infrequently enough at high levels (I don't exceed certain limits due to domestic limitations - unless those limitations are at the grocery store) one could get by using the 8 ohmer.

I AM cautious enough, however, to at least ask advice before I try.

Amps in question...

Sony ES

NAD 216THX

Several others...

Thanks!!

 

[John Kotches]

Colin,
You really have to ask the amplifier manufacturer whether they support driving a 4 ohm load with the amplifier bridged.
Because of the way bridging is done, you effectively HALVE the impedance of a speaker that is bridged, so that 4 ohm SV now looks like a 2 ohm load to the amplifier.
This can be a bit tough for many amplifiers to drive, which is why I suggested checking with the manufacturer
Regards,

 

[ColinM]

Bummer...I can see amps selling before I'd get an answer, or no tech support for older out-of-production types.

Guess I'll have to watch for the right thing.

Thanks

 

[TedO]

Colin,

I am using a Carver TFM15cb in bridged mode to power my 16-46cs+ with some success. All the info that I have shows you need to be careful bridging an amp into a 4 ohm load. The amp sees only half the ohm load per channel. Most amps can not handle this 2 ohm load so the manufacture's specify the minimum load to be 8 ohms when bridged. There are many "pro" style amps that will drive a 4 ohm load to 300-500 watts for fairly cheap. Check out partsexpress.com for some of these.

I have decided to go to the Samson S1000 route to drive my SVS, just to get more stable power at 4 ohms. We'll see if it make much of a difference.

TedO

 

[ColinM]

I wonder what the worst-case scenario is when a 4-ohm speaker is on a less-than-adequate bridged amp.
Smoke?
Fire?
Intense heat before shutdown?
Even while idling?
If I had the cash, I'd buy what works, obviously. But I'd probably also buy a second setup to abuse out on the back 40 to see if power caps or power supplies erupt in flames. It would be both academic AND entertaining...
Thanks for the replies, guys.

 

[TedO]

Worst case - Blown amp and a wrecked subwoofer

I am very wary to push my Plus hard because of the amp, thats why I will get a Samson, peace of mind I will not wreck anything.

TedO