Running the 950/7100 combo and love everything about it so far. I was running 7.1 but switched it back to a 5.1 with a Niles speaker switcher for my 4 surrounds. I like to use direct radiating for music and DVD-audio and switch to the bipoles for movies. Since I had two extra channels I decided to bi-amp my main speakers, Boston Acoustics VR-M50's. Now when I power down I get a noise from my main speakers 45 seconds after shut down that sounds like a jet engine shutting down. Not loud mind you, just a whirling sound that slows and then dissappears in about 15 seconds. Needless to say I'm confused, I checked all connections and everything is good. Any ideas or thoughts.

[This message has been edited by shawnb16 (edited June 18, 2004).]

did this happen when you werent biamping?

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No, only after. Needless to say I'm no longer biamping. I was just curious if anyone had ever encountered this. And since I've stopped biamping it has gone away.

no, i have never.

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I have the same type of sound coming from Klipsch RF-7's, also bi-amped, if you mean mid/highs get one channel of the amp(755) and the two tens get thier own channel of the amp(755). Two tower speakers are getting four channels of the 755 Amp. This has been going on for a year and I have just assumed it was the caps dischaging once the amp was going into standby mode. I don't think it is hurting the speakers.

that is not supposed to happen... electricity is an interesting thing though...

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it certainly is weird!! At first I thought that I was getting sometype of feedback from my projector fan, but then trying it with the projector off it still happened. I had biamped the speakers before and didn't have this problem. It has to be something with the power flowing out of transformer (or something) in the amp.

I know this might sound strange. However, I have seen this before with other brands.
Have you tried isolating the power to a differnet circuit on your pre/pro than what the amp is on?
It used to work on the Krell stuff when this happened.

Tom

Could be that because when you bi-amp, the DC path to ground on the mid/tweet section is nearly infinite with a typical crossover. The outlaw amp (and others too) may go unstable during shutdown while the pwr supply caps are discharging and osciallate some as cap voltage goes down, when there is no DC load. Sort of like when you power down an amp, you can still hear audio thru it for 15 secs or so while the caps discharge. Those caps hold alot of energy. Outlaw may not have modelled this condition, or maybe they did and the slight oscillation wasn't large enough to worry about. If the noise isn't too loud, I wouldn't worry about it. If it is loud, I'd probably go back to non-biamping.

I had the same thought as stabie regarding all of the signal to the mid/high section going through crossover capacitors that block low frequencies and DC. As an experiment, one might take either a 5 or 10-watt, 100-ohm resistor or a 1-watt, 1000-ohm resistor and place it in parallel with the mid/high section at the speaker cable terminals. The 100-ohm or 1000-ohm additional load would be negligible to the amp, but would allow very limited low frequency or DC current flow, should that solve the problem. Just don’t create a short in the process of installing the resistor! If the resistor solves the problem while not affecting the quality of the sound, and if the resistor never seems to get very warm, you might just consider installing the resistor in a way that allows it to safely remain installed.

Disclaimer: If you are not confident about doing this, don’t!

[This message has been edited by bestbang4thebuck (edited June 20, 2004).]

The non-DC return to ground issue certainly bears further investigation, however it sure doesn't say much for the stability of the power amplifier's design if it does go into oscillation because of this.

Personally, I don't think that's the problem, but it does bear checking out.