amplifier DC on 2" hf drivers, coupling caps? |
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bob4
Old Croc Joined: 29 February 2004 Location: Finland/Germany Status: Offline Points: 1842 |
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Posted: 07 April 2017 at 12:39pm |
Greetings gentlemen,
apologies for the rather beginnerish question, despite my wannabe-expert ramblings on this forum.... Doing some system tuning, and have a question about amplifier dc I have some naked comps for a threeway system. I want to connect them straight to the hf amp, but trying to cultivate diligent practice, i decided to check first that the amps dont output any dc. Turns out there are 2-5 mV DC coming from The various amps. Is it safe to connect a hf driver to an amp with this amount of dc offset? If not, which spec of coupling caps should i use? EDIT: Comps are b&c de75 Bless, Bob Edited by bob4 - 07 April 2017 at 12:40pm |
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Earplug
Old Croc Joined: 03 January 2012 Location: Europe Status: Offline Points: 7199 |
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A few mV is normal - even up to 100mV or so is not unusual on older amps. Any more and I´d get them serviced, but 2-5mV is nothing.
In any case, a blocking capacitor is a good idea. Use a capacitor which gives you a -3dB point at least one octave below your crossover frequency. Edited by Earplug - 07 April 2017 at 1:14pm |
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Earplugs Are For Wimps!
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bob4
Old Croc Joined: 29 February 2004 Location: Finland/Germany Status: Offline Points: 1842 |
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Cheers! What kind of voltage rating do you reckon could be good? 50ish volts? Or more like 100?
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studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3863 |
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For high power PA work use minimum 250 volt, non-electrolytic/film type capacitors. It's actually the AC current rating that's important - but that's not quoted by the majority of manufacturers.
However, it scales with the voltage rating, and I've found from experience that 50v caps will blow up quickly, 100v ones will blow up eventually (that goes for electrolytics as well as film types), whereas 250v and 400v types seem to last a long time. The thin foils and dielectrics in low-voltage types just can't take the continuous power.
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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
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Earplug
Old Croc Joined: 03 January 2012 Location: Europe Status: Offline Points: 7199 |
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Earplugs Are For Wimps!
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madboffin
Old Croc Joined: 03 July 2009 Location: Milton Keynes Status: Offline Points: 1537 |
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These are probably the best, many pro manufacturers use them:
http://www.falconacoustics.co.uk/alcap-claritycap-solen-audio-capacitors/solen-scr-capacitors-400v.html |
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