lm1875 problems?

billyreal · 15th January 2010, 07:40 PM

Hey all- new to this forum and new to building chip amps,(up till now all tube), running into a problem with my lm1875 it powers up and sounds great for 2 min, and then fizzes out ,if I turn it off wait a minute and turn it on it does the same thing any ideas?

mjf · 15th January 2010, 09:55 PM

hello.
does it run hot?
greets..........

billyreal · 16th January 2010, 12:58 AM

Its not hot to the touch, Im using a bipolar power supply at about 14v, does the heatsink need to be grounded?

Cal Weldon · 16th January 2010, 01:50 AM

Moved to chip amps. Troubleshooting is for concerns with the forum.

AndrewT · 16th January 2010, 12:26 PM

precisely, tell us how you have coupled the chipamp to the heatsink and tell us the rating of the heatsink and whether it is exposed to ambient air or stuffed inside a shoebox.
A few pics might help.

billyreal · 16th January 2010, 01:41 PM

its bolted with a mica washer to a heatsink that was in a marshall amp ,wich was using a tda2050,there is a little heatsink grease on it its in the open air ,I dont have a preamp connected just trying to get the power amp up and running thanks

billyreal · 16th January 2010, 04:18 PM

got it figuired out, thewire from pin4 to 1 ohm resister was about 6 inches long ,I put the resistor right on the pin and ,she purrs like a kitten ,thanks for all the info on this site!

15th January 2010, 07:40 PM	#1
billyreal diyAudio Member Join Date: Jan 2010	lm1875 problems? Hey all- new to this forum and new to building chip amps,(up till now all tube), running into a problem with my lm1875 it powers up and sounds great for 2 min, and then fizzes out ,if I turn it off wait a minute and turn it on it does the same thing any ideas?

16th January 2010, 01:50 AM	#4
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Moved to chip amps. Troubleshooting is for concerns with the forum. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

16th January 2010, 12:26 PM	#5
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	precisely, tell us how you have coupled the chipamp to the heatsink and tell us the rating of the heatsink and whether it is exposed to ambient air or stuffed inside a shoebox. A few pics might help. __________________ regards Andrew T.

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15th January 2010, 09:55 PM	#2
mjf diyAudio Member Join Date: Jan 2009 Location: upper austria/near linz	hello. does it run hot? greets..........

16th January 2010, 12:58 AM	#3
billyreal diyAudio Member Join Date: Jan 2010	Its not hot to the touch, Im using a bipolar power supply at about 14v, does the heatsink need to be grounded?

16th January 2010, 01:41 PM	#6
billyreal diyAudio Member Join Date: Jan 2010	its bolted with a mica washer to a heatsink that was in a marshall amp ,wich was using a tda2050,there is a little heatsink grease on it its in the open air ,I dont have a preamp connected just trying to get the power amp up and running thanks

16th January 2010, 04:18 PM	#7
billyreal diyAudio Member Join Date: Jan 2010	got it figuired out, thewire from pin4 to 1 ohm resister was about 6 inches long ,I put the resistor right on the pin and ,she purrs like a kitten ,thanks for all the info on this site!

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