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Old 14th January 2013, 11:16 AM   #131
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desolder (pull out ) either R29 od R47 and then try entire procedure again

something is wrong with your measurement - voltage across R29 and R47 must be the same
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Old 15th January 2013, 06:23 AM   #132
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Doh! Sorry, fat fingered one number.

D5: 8.92V
R47: 4.83V
R29: 4.84V
R30: 3.0V
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Old 15th January 2013, 07:29 AM   #133
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Slightly different numbers after an hour of warm up if it makes a difference:

D5: 8.99V
R47: 4.98V
R29: 4.99V
R30: 3.1V

During this commercial break... can I also confirm that it's important to turn on your source BEFORE turning on the amps? I noticed some pretty big turn on thump when I didn't initially have my source already one. Woofers extended outward pretty far... scared me a little bit but doesn't seem to have done any damage.
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Old 15th January 2013, 10:22 AM   #134
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just do what I wrote in #131

regarding thump - that's normal , it doesn't have anything with your amp , but with common logic
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Old 15th January 2013, 04:57 PM   #135
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Great, I'll give that a try tonight. Thanks for your help! I'm not really sure why both resistors are there in the first place... perhaps just power handling so as to not require higher wattage resistors? Or perhaps for people like me who just need an easy way to get to zero absolute DC offset?
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Old 15th January 2013, 05:10 PM   #136
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dunno ;

someone was keen to put plenty of parts , probably to invoke better sound ?



properly sized R30 and Rp1 are all you need there , covering all possible variations
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Old 17th January 2013, 01:44 AM   #137
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Removed R47 and now when I turn the pots the OTHER direction fully, I can only get to +2.5 and +1.5 V. So it looks like I need to add another resistor back in. I should be able to find something in the ballpark. Any suggestions? Maybe something in the 100R range?

Also, I noticed the heat distribution is backwards now... although much more even now.
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Old 17th January 2013, 01:56 AM   #138
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what +2V5 and what +1V5 ?

edit : I'm going to sleep now

read ya tomorrow
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Old 17th January 2013, 02:07 AM   #139
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just thinking

if you now have out to gnd offset in positive (instead of previous negative ) , just put R47 back

but - this time not 475R ; put 1K for start then - if necessary - 910R or 820R


good night .....
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Old 17th January 2013, 03:14 AM   #140
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Yes, that was what I was thinking. I'll try 1K first as you suggested. Thanks!

BTW, after fully warmed up, I have 1.6V and .3 V (positive on both) now. Seems to not be drifting anymore.
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