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Old 12th August 2005, 06:51 PM   #421
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Default Heat Generation

I am still messing with my first one. I wish the camera would take pics low rez enough to post. But one thing, my heatsinks barely get warm.
I do not know if this good or bad. One thing, I used 0.01% resistors for the 22K and 47K. This MAY help it to generate less heat idling. It has never been hooked up to my speakers, they are single drivers that cannot handle a lot of dc or power. Waiting till the unit is working as I like it to really test. It has only been hooked up to some cheap speakers to see if it plays and check for hum. I have yet to play a whole song through.


George
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Old 12th August 2005, 07:49 PM   #422
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My heat sink never gets hot either. Are there any other problems you are seeing that are keeping you from trying it out for real?
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Old 12th August 2005, 07:53 PM   #423
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Default Worried

Quote:
Originally posted by BrianDonegan
My heat sink never gets hot either. Are there any other problems you are seeing that are keeping you from trying it out for real?

I am worried about a measured voltage. Measuring the metal tab on the LM3886 to ground I get a variation in this voltage from one chip to the other. Is this normal? This is my first stab at chip amps.
Hope to rerun some wires this weekend and get it settled in main system soon.


George
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Old 12th August 2005, 07:57 PM   #424
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Default Re: Worried

Quote:
Originally posted by Panelhead



I am worried about a measured voltage. Measuring the metal tab on the LM3886 to ground I get a variation in this voltage from one chip to the other. Is this normal? This is my first stab at chip amps.
Hope to rerun some wires this weekend and get it settled in main system soon.


George

Yes its normal to get DC there, the tab carries the negative rail, if you are using the T package. Though the variance sort of confuses me...
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Old 12th August 2005, 08:25 PM   #425
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The tab is electrically isolated from the case, right? If not, your case (or heatsink) has rail voltage. That would be bad, but may explain the fluctuation.
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Old 12th August 2005, 08:34 PM   #426
homer09 is offline homer09  Canada
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Default Re: Heat Generation

Quote:
Originally posted by Panelhead
I am still messing with my first one. I wish the camera would take pics low rez enough to post. But one thing, my heatsinks barely get warm.
George
im pretty sure your camera allows you to choose different resolutions... check your user manual.
if not, you can resize in any free picture editor (irfanview) to fit forum requirements.
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Old 12th August 2005, 09:41 PM   #427
maf_au is offline maf_au  Australia
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Default Re: Heat Generation

Quote:
Originally posted by Panelhead
I am still messing with my first one. I wish the camera would take pics low rez enough to post.
Another option is Picasa - it's a photo management software for windows by google that works somewhat like iPhoto does on the mac. I've switched a few people who were having dramas with the oem software to it, and they're loving it.

http://picasa.google.com/index.html

Some cameras come with a light version of photoshop, that works well too. A lot of the oem software is pretty klunky.

Michael
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Old 13th August 2005, 12:07 AM   #428
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Default Re: Re: Worried

Quote:
Originally posted by Russ White



Yes its normal to get DC there, the tab carries the negative rail, if you are using the T package. Though the variance sort of confuses me...
Me too, one is at -34, the other at -29! Why I DO NOT KNOW. They should be the same.
I suspect a problem with the LM3886. Or the connections. The LM3886T are isolated with mica and paste. The chips and the heatsinks are not hot, but the 1000 ohm dropping resistors will tatoo you. Checking the whole board is isolated from the case.
Rather than clip leads and replace the suspect LM3886 I am going to build another board. I learned a little on the first one, this one should be better.

George
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Old 13th August 2005, 11:07 AM   #429
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Did you check over your solder joints for cold joints or bridges?
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Old 13th August 2005, 12:07 PM   #430
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Default Re: Re: Heat Generation

Quote:
Originally posted by maf_au


Another option is Picasa - it's a photo management software for windows by google that works somewhat like iPhoto does on the mac. I've switched a few people who were having dramas with the oem software to it, and they're loving it.

http://picasa.google.com/index.html

Some cameras come with a light version of photoshop, that works well too. A lot of the oem software is pretty klunky.

Michael

Maf_au has a good point

Use Picasa to email the picture to yourself. It will compress the picture for you.
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