I have a strange problem with the following setup:

Outlaw 1050
Outlaw 750
Parasound HCA-1500A
Sonus Faber Concertos (fronts)
Sonus Faber Solo (center)
Energy Encore 2's (surrounds)
Energy Encore 1 (center surround)
I am driving the fronts with the Parasound, the center, surrounds and center surround with the 750.

The center channel is a Sonus Faber Solo, which I want to bi-amp using two channels on the 750.

I removed the shorting bars on the speaker and connected the Center channel preamp out to two channels of the 750 with a Y connector.

I wired the two channels to the high and low connectors on the speaker. Everything sounds great.

About 15 seconds after I power off the amplifier, I hear a high pitched whine that descends in pitch for about 5 seconds from the tweeter in the center channel.

I know this is coming from the 750 because I hear it even when I disconnect the preamp inputs from the amp.

When I replace the shorting bars and connect the speaker conventionally with one pair of wire from one amp channel the sound disappears.

When I remove the bars and bi-wire from a single channel on the amp, there is no whine.

When I bi-amp using the two channels on the Parasound, no whine.

When I amp the Solo's tweeter from the center speaker terminals on the 1050 and the bass from a single channel on the 750, there is no problem.

Anybody else trying to bi-amp with the 750 out there?

Thanks,
Tony.

I'm biamping some Paradigm Reference 100's (and using the 5th channel for my center channel). I think the whining sound is the saved up power coming coming out of the capacitors. You'll notice that the music keeps playing briefly after the power is turned off, then gets distorted, then turns to whining, then ceases. It is merely the power reserves draining. My other amps do it too.

Thanks for the feedback. I got the same info from Scott at Outlaw CS. I followed up with Parasound and found out that there's no whine from the HCA-1500A because it's protection circuit kicks in on power down and so the capacitor drain never makes it out to the speakers.

I actually have moved back to a simple bi-wired configuration from a single channel on the 750. That leaves me enough channels to move to 7.1 later this year.






[This message has been edited by palmer (edited August 18, 2003).]