Outdoor Movie Night - 5.1 to PA question

[Funky54]

For an outdoor movie night I'd like to run 5.1.

Can I take an AV preamp and run out of it with RCA analog channels into an adaptor to 1/4" unbalanced and then directly into my PA amps?

Outlaw Audio 950 (AV Preamp) with RCA analog outs>
RCA to 1/4" unbalanced adapters>
Peavey 8.5 (amp 1) Left main signal into left channel of Peavey / right signal to right channel
Peavey 8.5 (amp 2) Left surround signal to L channel of Peavey / right to right channel
Peavey 8.5 (amp 3) Center signal to Left amp channel
Sub signal from preamp to crossover to Right side of amp 3 to Sub

Is this right? I could just bypass PA board, effects and Stereo EQs.

 

[Chip Chester]

I'd do a pre-show test to see if the -10 signal will drive the amps enough to achieve whatever level of "loud" you need. If not, just take each channel into your PA board, and drive the amps with the direct outs of each channel (acting like a line-level amp). Set 'em all equally.

If the amp driving center channel + sub doesn't have enough guts for simultaneous signals, you could do center + left surround on one amp, and sub + right surround on the other. The surround channels won't be working as hard. That case would likely only exist if you were pushing the amps to their power-supply limits, though.

Chip

 

[Funky54]

I'd do a pre-show test to see if the -10 signal will drive the amps enough to achieve whatever level of "loud" you need. If not, just take each channel into your PA board, and drive the amps with the direct outs of each channel (acting like a line-level amp). Set 'em all equally.

If the amp driving center channel + sub doesn't have enough guts for simultaneous signals, you could do center + left surround on one amp, and sub + right surround on the other. The surround channels won't be working as hard. That case would likely only exist if you were pushing the amps to their power-supply limits, though.

Chip

The PA board only has 4 sends so I couldn't get 6 channels that way. I think I follow your thought on the center / sub. The Peavey 8.5 is 270 watts rms's at 8 ohm and my center speaker would only require 180 watts. The sub is a 4 ohm sub requiring 400 watts and the peavey channel does 475 watts Rms at 4 ohm. So I think that part is ok.

When I played in bands I drove those peavey amps most of the time at 2 ohm all night long with no problems. I think they'll be ok. The bag end speakers are really really efficient. I use to play out side for 300 - 400 wedding gigs with no problems. The only real issue I see is I don't know how the AV preamp's signal will be in comparison to what my board would normally give the amps?

 

[Chip Chester]

I was more talking about using a channel insertion output, or a direct out, from each input channel, and getting your boost by adjusting channel input gain control. (Assuming your board has 6 input channels.) Not really talking about using pre or post fader effects sends. But if it's at least a 6 input board with 4 effects sends and stereo out (with decent routing) you could do 4 pre-fader sends (with the main mix bus faders at zero) and two other inputs panned left and right to stereo outs for the other two channels. That would give six adjustable line gain stages that are independent. You'd have to go thru and set them up evenly (with some external meter, like a cassette deck) so that the outputs are all equal when passing tone. Not unity gain, but rather whatever gain you actually need.

You'll have to set up and test to see if you need the additional gain offered by the mixer, though.

Chip

 

[Sam Cogley]

Can't you just change the number of channels on your preamp?

 

[whoaru99]

For an outdoor movie night I'd like to run 5.1.

Can I take an AV preamp and run out of it with RCA analog channels into an adaptor to 1/4" unbalanced and then directly into my PA amps?

Outlaw Audio 950 (AV Preamp) with RCA analog outs>
RCA to 1/4" unbalanced adapters>
Peavey 8.5 (amp 1) Left main signal into left channel of Peavey / right signal to right channel
Peavey 8.5 (amp 2) Left surround signal to L channel of Peavey / right to right channel
Peavey 8.5 (amp 3) Center signal to Left amp channel
Sub signal from preamp to crossover to Right side of amp 3 to Sub

Is this right? I could just bypass PA board, effects and Stereo EQs.

Direct from unbalanced pre/pro using necessary adapters to pro amps should work fine. Just be sure the cables/adapters are from RCA to 1/4" mono/TS, not TRS.

"Consumer level" to "pro level" does not apply to pre out/main in connections so there are no level matching converters necessary.

Sure, gain may be different than what you're used to with the mixer, but the volume knob, channel trim/calibration, and the gain controls on the amps should be all you need.

 

[vinyldavid]

You should be good to go . Most consumer preamps can deliver higher than -10 signal level anyway and drive the pro amps to full level.

 

[Funky54]

Thanks guys! I appreciate the feed back.