Setting voltage limits

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himhimself
Posts: 278
Joined: Fri Nov 13, 2015 9:34 pm
Location: Bloomington IN

Setting voltage limits

#1 Post by himhimself » Fri Jul 05, 2019 10:07 am

I finished my breakout panel and wired the sub cable to take the +1/+2 from the amp and send it to +1/-1 on the panel so I can bridge my Crown. Obviously I'll need to reset the limiter on my PA2 accordingly. Can you please verify my steps as follows;
  • Hook up multimeter to the speaker leads from the amp (without speaker)
    • Set to AC
      • Play a tone around 50 or 60hz
        • Set amp to max, push up fader, volts should be over 60V
          • Increase limiter setting until output drops to 50V (what I am using as max for 3012LF loaded T30s
          One question I have - wouldn't the frequency from the tone generator influence the voltage? My app can sweep the frequencies. Would it make more sense to set a slow sweep back and forth between 35hz and 70hz just to be sure I didn't select a single frequency that may not give the max voltage output?
2xT30 (20", 3012lf)
4xOtop Jarray

Bruce Weldy
Posts: 6807
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Setting voltage limits

#2 Post by Bruce Weldy » Fri Jul 05, 2019 10:22 am

himhimself wrote:
Fri Jul 05, 2019 10:07 am
I finished my breakout panel and wired the sub cable to take the +1/+2 from the amp and send it to +1/-1 on the panel so I can bridge my Crown. Obviously I'll need to reset the limiter on my PA2 accordingly. Can you please verify my steps as follows;
  • Hook up multimeter to the speaker leads from the amp (without speaker)
    • Set to AC
      • Play a tone around 50 or 60hz
        • Set amp to max, push up fader, volts should be over 60V
          • Increase limiter setting until output drops to 50V (what I am using as max for 3012LF loaded T30s
          One question I have - wouldn't the frequency from the tone generator influence the voltage? My app can sweep the frequencies. Would it make more sense to set a slow sweep back and forth between 35hz and 70hz just to be sure I didn't select a single frequency that may not give the max voltage output?
Set your master fader to unity and bring up the volume of the tone via a channel until the output on the board is just hitting unity on your meter. Then check to see what voltage the amp is putting out and adjust the limiter until it gets down to 50. Then, while watching the volt meter, slam the master fader all the way up - if the volt meter stays at 50 then you know you've set it correctly.

As far as the frequency.....remember that voltage is voltage. The frequencies that you sweep will all have a different impedance so that wouldn't tell you anything or be productive as far as limiting. So, just set it on 60hz and leave it.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Bruce Weldy
Posts: 6807
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Setting voltage limits

#3 Post by Bruce Weldy » Fri Jul 05, 2019 10:23 am

Oh, and be sure and turn off the AFS if it's on. It will see the tone as feedback and kill it. Ask me how I know......

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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