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Old 12th July 2006, 11:13 AM   #1
kenny12 is offline kenny12  Australia
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Default Loud Buzzing on Start? [Orginal T-amp]

I have done the stealth mod with a 8.2uF Bennic Capacitor

i get a very loud buzzing sound on startup that lasts for less than half a sec then everything is fine.

what can i do to fix it?

thanks
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Old 12th July 2006, 01:09 PM   #2
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The noise on power up is related to the capacitor size. Most people use 2.2uf which eliminates the original bass roll-off and only introduces a very slight turn on noise. I don't think there is anything to gain going to higher values.
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Old 12th July 2006, 01:10 PM   #3
kenny12 is offline kenny12  Australia
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it was the only high quality cap i had, is there anyway i can reduce this noise?
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Old 12th July 2006, 01:42 PM   #4
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Default Start-up oscillation...

This is a known issue with some of the Tripath chips. Its due to the voltage at the input pin, charging up the cap, but in doing so, causes the gain-op/amp to ocillate while the voltage stabalises at the input ....
Designers of amps with tripath chips tend not to go much above 4 mic for this reason....

I have successfully used a 3.3 mic cap with no start-up issues with the 1st gen TA2020-020 chips....
I think the chip's input impedance is around 100K, so theres no need to go higher than 3 mic really....
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