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Amp Settings

DavoDavo Posts: 2
Any ideas..
Trying to get aquainted with Driverack PA.
5 piece band, 4 vocals, 2 electric guitars, 1 acoustic guitar, bass guitar and drums.
PA - Spirit E12, Driverack PA, Crown XLS 402, Yamaha S15 pair and S10 pair.
Have specially purchased Crown XLS 402 to take advantage of preset amp tunings to drive Yamaha's the DrvrkPA is telling me to set amp at 32%. Why ? I dont understand this.


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    mikejoeydbxmikejoeydbx Posts: 134

    You need to set this setting to match the attenuator on your amp. This setting tells the Driverack PA where to set the X-over gain and Limiter threshold. It is attempting to set your gain structure between the Driverack and the amplifier. It then sets the Limiter so that you cannot clip your amplifier. Check out this link from Crown on gain structure. It may help clear things up.

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    Yeah, this misconception that you won't get the full power from the amplifier if the knobs aren't turned all the way up...I wish I could make a worlwide announcement that this myth is absolutely untrue.

    Davo, the knobs on a power amplifer do not in any way control the amplifier's OUTPUT. They have no control over how much actual power the amplifier puts out whatsoever. What they DO accomplish is they allow you to adjust the amplifier's \"input sensitivity\". The input sensitivity of an amplifier is the amount of voltage required at the input of the amplifier to make the amplifier output swing to maximum clean power output.

    By dropping them down to 32%, you're making the input of the amplifier less sensitive, which eliminates the low level noise/hiss coming from everything before the amp from coming through, resulting in a quieter system. This also allows you to get a LOT more gain from your channel gain controls on your mixer. By turning down the amplifier knobs, the amp will still put out full power...it will just take a MUCH bigger signal to get that, which is what you want to make your system as quiet and as clean and clear sounding as possible.

    To summarize, basically the knobs on a power amp, normally called \"input attenuators\"(because they attenuate the INPUT signal, not the OUTPUT signal)...input attenuators are there so that you can match your amp's input sensitivity to match the output level of your mixer. Most power amps hit clip with 1-2 volts on the input with the attenuators fully cranked, whereas most mixers can put out around 9-10 volts. By cranking them all the way, you end up sacrificing a good 7-8 volts of gain from your mixer because your amp hit clip LONG before you were able to push as much signal out of your mixer.

    On top of this, you don't want amps that put out LESS power than your speakers are rated for. That's just asking for blown speakers. You also don't want an amp that's rated for exactly what your speaker is rated for either. You want amps that will still have power left in reserve once you're at concert volume. Otherwise you'll end up pushing and stressing your amps/speakers to get any kind of punch and volume out of your system.

    Hope this helps.

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    GadgetGadget Posts: 4,915
    Jon, you finally made it! Welcome!For those who haven't been able to make it work yet, I had to use Mozilla to register... I have made \"tech support aware of the problem, and they are looking in to it...
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    Hey PA System Inspector Gadget...I bet all those people who had problems registering by now have not been coming to the site in the last couple weeks...so you basically just wasted your time typing that post LOL!

    BTW how much did YOU have to drink tonight!?

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    GadgetGadget Posts: 4,915
    funny you should ask... 8)
    My buddy Dean got dropped off while his wife and mother-in-law went shopping etc..etc...etc........ :roll: and whenever he stops by... :!:
    so we pretty much got the jag on :lol: ..totally.. :shock: Captan Morgan style :? (he isn't allowed to drink Whiskey...it gets REALLY ugly when he does :oops: ) So now I have to put in a tranny with a hangover :(
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