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Old 27th October 2008, 06:44 PM   #11
rwaudio is offline rwaudio  Canada
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I've been checking the enclosure AND main aluminum block, there is thermal paste between the chips and the main aluminum block, however there is no paste yet between that block, the spacer and the enclosure. With no fan the enclosure warms up very quickly and to a similar temp to the main block. There is a "good" thermal connection between all of these parts, but should get better when there is a proper layer of thermal paste between them. So at these power levels heat is not an issue, however I have not been able to run the amp higher than about 80-100watts of rms output because of the bench supply I'm using.
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Old 30th October 2008, 08:58 AM   #12
Stream is offline Stream  Russian Federation
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Very nteresting! Waiting for the continue
Please write a little more about PS...
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Old 7th November 2008, 03:07 PM   #13
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I would love some information on this project also...

J
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Old 9th November 2008, 02:43 PM   #14
ide2003 is offline ide2003  Indonesia
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Quote:
Originally posted by Stream
Very nteresting! Waiting for the continue
Please write a little more about PS...

Quote:
Originally posted by j.wright
I would love some information on this project also...

J
yup..agreed!!..how is the PSU things going rwaudio? I'm just finishing my daughter's LM3886..(its just sounds awesome..) and have this urge to make one or two for my car..(no power amp, just 4x50W head unit..) love to hear some updates..thanks alot

TPS_nuB
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Old 13th November 2008, 02:34 PM   #15
rwaudio is offline rwaudio  Canada
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The power supply is probably one of the simplest parts of the amp. It's based on http://sound.westhost.com/project89.htm (use the bottom schematic) which is actually a very simple to build unregulated SMPS I changed a few things to fit my application but the theory and basics can be learned there. Just make sure your traces are large enough for the current and the layout is simple with short traces or there can be instability, I actually tried to breadboard the circuit last night for another smaller project and nothing at all worked. I had to switch to a dc/dc converter for my +/- 20v so that being said the circuit CAN be picky and may not work with poor layout. The transformer I wound myself using the F-140-77 core from CWS Bytemark http://www.cwsbytemark.com/index.php...ndex&cPath=221
I simply used 4+4 turns on the primary made up of multiple twisted strands of fairly fine magnet wire (much easier to work with than 1 or 2 strands of heavier wire) The secondary is made of 9+9 turns using a few less strands then the primary due to the lower current. It operates at 52kHz and runs cool and noise/vibration free. The only thing I would do different next time is take better care in stripping the varnish off the leads, as I had a few strands that didn't want to solder very well at first making it a big pain to strip later. Once I get everything together I can post my version of the schematic, but it is very similar to the one linked above.

I've built 3 versions of that smps sofar, the first two being point to point wired on prototyping board, using leftover caps/transformers/connectors from dead car amps. All worked very well, the version on the breadboard was the first time this design hasn't worked perfectly for me the first try.

I can give limited help to anyone trying to build their own smps, but since it's not my design I can't garantee yours will work too.
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Old 13th November 2008, 02:41 PM   #16
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I am looking to build a 500 watt power supply... Any help ?
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Old 13th November 2008, 02:43 PM   #17
rwaudio is offline rwaudio  Canada
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With a few more switching mosfets or simply better ones and a larger toroid (F-240-77) 500W should be easy.
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Old 13th November 2008, 02:44 PM   #18
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I really don't know just how to modify the PS you used to attain 500 watts...? Any suggestions...?

Thanks !
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Old 13th November 2008, 02:59 PM   #19
rwaudio is offline rwaudio  Canada
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j.wright you've got mail.

for reference here is a table giving a rough idea of the power output you can expect from a given core at a given freqency.
http://users.catchnet.com.au/~rjandu...ts/tut_7a.html
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Old 13th November 2008, 04:20 PM   #20
wazzy is offline wazzy  Zimbabwe
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i'm sure we're all watching and waiting patiently, great work.
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