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Old 10th December 2006, 04:37 PM   #11
AndrewT is offline AndrewT  Scotland
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Hi J,
what voltage are you running your chip from?

I assumed that you could achieve about 24Vpk from +-30Vdc.
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Old 10th December 2006, 05:08 PM   #12
jaste is offline jaste  Sweden
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I got a transformer with dual 30 volts secondaries, after rectifying that should be around 40 volts right? That may be a bit to much for the 4780 chip so then I regulate it down to whatever but atleast 34 volts since the lm338 requires atleast 6 volts regulation (i think). So maybe 30-34 volt supply to the chips. And again lm338 max output 5 amps, and I want to run one chip in paralell config per channel and there will be two channels, so two chips to drive. I hope you understand, cause i lost myself somewhere...
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Old 23rd May 2010, 03:55 AM   #13
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Why parallel and not bridged?
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Old 23rd May 2010, 06:20 AM   #14
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Quote:
Originally Posted by jaste View Post
4 ohm load
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Old 24th May 2010, 07:29 PM   #15
AndrewT is offline AndrewT  Scotland
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A 4ohm load is going to demand a lot more current than an 8ohm load.
A 5A limit from the regulator is not, in my opinion, going to deliver the goods.
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Old 25th May 2010, 08:46 PM   #16
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Also a 2x40 VDc supply is a bit to much for a 4 Ohm load. I suggest looking for a transformer with a 2x22 Vac secundairy. Given the very good PSRR of the Overture chips, I do not see the need of a regulated supply.
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Old 26th May 2010, 04:10 AM   #17
GAH is offline GAH  Fiji
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I've bridged a LM3875 chip amps (Audiosector kits - Dual Mono) running 6 ohm (nominal) speakers without any sonic or heat problems. Admittedly, listening levels are always kept at low to medium levels and the chips are well heat sinked.
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Old 26th May 2010, 12:22 PM   #18
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by GAH View Post
I've bridged a LM3875 chip amps (Audiosector kits - Dual Mono) running 6 ohm
and the smoothing cap voltage is?
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Old 26th May 2010, 04:46 PM   #19
GAH is offline GAH  Fiji
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I'm using two 300va transformers with 22v secondaries. This feeds the chip amps with 31 volts DC.
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