nuforce ref9s and active speakers

adrianlucy · « **on:** 11 May 2006, 05:53 pm »

I've recently demo'd a pair of the reference 9s and was most impressed. However in the instructions it say's they cannot be used with active speakers (mine are definitive technology bp2002s). Anyone know what i can do about this compatability problem?

Wylie Williams · « **Reply #1 on:** 11 May 2006, 08:24 pm »

As I understand the definition an "active speaker" contains its own amplifier so the only signal that should be sent to it should be a line level signal from a preamp/EQ/processor. I am not familiar with your speaker. It may be one of those with a built in subwoofer amp but needing an external power amp for the mid/high section.

rustydoglim · « **Reply #2 on:** 12 May 2006, 04:32 am »

For those speakers with active subwoofer, you have to check with the speaker manufacturer. Now that there are a lot of icepower based amps out there (similar to icepower, Nuforce has DC offset versus ground), speaker manufacturers are going to change their design to accommoate these amps (Martin Logan made that change since Nov 2005 for example).

Wylie Williams · « **Reply #3 on:** 12 May 2006, 01:54 pm »

Jason, I am puzzled by your post. As I see it if a speaker has a powered subwoofer built in there is only a mechanical connection to the other drivers in the cabinet, so it does not seem any different to me than using an amp (whether NuForce or any other) with a normal (let's call it "passive") speaker and a separate self-powered (active) subwoofer in its own cabinet.

If there were some electronic interaction or connection I could see it but I can't visualize it.

My knowledge of electronics exists only at a very basic level, so be kind in your explanation.

Wylie Williams

rustydoglim · « **Reply #4 on:** 13 May 2006, 09:37 am »

If the active subwoofer uses another line level input (for example, second set of output from the preamp), then it doesn't matter.

But in many cases, the active subwoofer uses the speaker terminal outputs of the amp (which has high DC offset versus ground) and that could cause a short to the ground depending on the design.
Only the speaker manufacturer can help you. With so many icepower based amps out there, speaker manufacturers will avoid this problem.
For example, Martin Logan upgraded the Summit speaker since Nov 2005 to allow such configuration.