Amp limiters... why cant i...? |
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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Posted: 28 December 2018 at 9:41am |
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Im wondering why people calculate their limiter settings.
Im not particularly electronics or amp savvy. (Guess i wouldn't need to ask if i was)
Why can't you just unplug the speakers and measure the voltage with the amp set to 11 and dial the limiters down until its acceptable? Its clearly not this simple as i can't find anyone suggesting this. What am i missing? |
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Timebomb
Old Croc Joined: 11 October 2004 Location: Lancaster Status: Offline Points: 2717 |
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You can and its not a bad way to do it, worth noting that some amps will drop there output under load more than other amps, ideally its better to do it with the speakers connected, even if its just for a quick check.
Voltage gain / input sensitivity on amps is normally given at 8 ohms, and can change at 4 ohms and more so at 2 ohms, so calculating limiter settings has its draw backs too...
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James Secker facebook.com/soundgearuk
James@soundgear.co.uk www.soundgear.co.uk |
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Earplug
Old Croc Joined: 03 January 2012 Location: Europe Status: Offline Points: 7216 |
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The main problem is that your speaker impedence is a moving target. It will change with frequency, so checking with speakers connected is pretty important. Calculations with a nominal 4 or 8 ohm is just guesswork. And as noted above, most amps will drop a few volts under load. |
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Earplugs Are For Wimps!
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Tonskulus
Registered User Joined: 15 September 2017 Location: Finland Status: Offline Points: 425 |
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Having some Tamp TA1400's, they have decent built-in limiters. Great behaviour in stereo (8ohm/ch) mode, limiting output voltage to somewhere around 64Volts/channel. However there is problems when driving low impedance loads / bridge mode @ 8ohm. Severe clipping may occur as amplifier is unable to give 2x64V=128Volts. Clipping starts at around 105Volts, long way before limiters will activate..
But as mentioned, speakers has moving impedance with frequency etc so limiting only input voltage is just guessing what happens in output stage.. Edited by Tonskulus - 28 December 2018 at 1:46pm |
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kedwardsleisure
Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4949 |
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some amp owners manuals do recommend setting limiters up as you say. But I would advise that limiters are no substitute for a proper gain structure as part of a well-matched system which should be done first, then the limiters added as a last resort.
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Kevin
North Staffordshire |
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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Did you even read my question?
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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Ok. I'm up for trying this.
Is there a guide or how to anywhere?
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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Why would it have to be super accurate?
Ive got a fluke multimeter which will probably be sufficient, but i wonder why you think it needs to be particularly accurate. Can you show me your workings?
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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You think, or it is? Show me facts not guesswork.
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imageoven
Old Croc Joined: 28 March 2007 Location: Scotland Status: Offline Points: 2186 |
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I just googled analog multimeter, one of the many that came up was under £7 so 'probably' not especially high quality or acurate.
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Keep pushing on, things are gonna get better.
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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5176 |
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The only thing that was not mentioned by the previous comments is... What exactly are you protecting? The majority of modern day amplifiers offer an on board limiter to prevent severe clipping. Most sound man use stand alone limiters to protect their loudspeakers from receiving too much power providing, the on board limiter in the amplifier is not adjustable. So are you protecting your loudspeakers from too much power or, are you using an amplifier that does not include an on board limiter in which, you need to use a stand alone limiter to prevent the amplifier from clipping? Best Regards, Edited by Elliot Thompson - 28 December 2018 at 10:28pm |
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Elliot Thompson
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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have you googled fluke?
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