Reduce "pop" noise when power on/off

veckans · 1st January 2009, 11:45 AM

I have a Tripath TA2024 amplifier that I really like the sound, and quality of. There is one problem with it however, it produces a "pop" sound when I turn it on/off. It isn't very loud but it ruins the quality feeling. And I'm also told this "pop" can demagnetize speakers after a while, is this true?
I have also heard that this "pop" noise is caused by the input capacitors charging up, and one way to fix it would be to change to max 2uF capacitors instead of the 470uF that are currently there.
I have measured the DC Offset of this "pop" and it was at most 125mV for one channel, and 90mV on the other.

So I wonder how I can fix it cheap. I saw on the charlize (tripath amplifier) info page that you can put the amplifier in "sleep-mode" instead of turning it off by just adding a 260ohm resistor on the input power line (12V). I tried this but the power LED was still on even if dim. The "pop" didn't disappear either, it was just slightly reduced.

Thanks for any help!

hoka · 2nd January 2009, 07:01 AM

wich one do you have?

can you post a picture?

the 470uF caps are most likely not the input caps

veckans · 2nd January 2009, 10:46 AM

This is how the PCB looks:

But, now I tried "sleep-mode" with a higher ohm resistor (330ohm this time) and for some reason the "pop" is very faint now, and non-existant on turn off, something I can live with

audiosteve · 2nd January 2009, 03:22 PM

It is hard to know for sure without a schematic, but this board has two multi-turn pots that appear to be for adjusting the output offset (by adjusting the input DC offset). If you measure the DC output and adjust the pots to get the output DC level near zero I will bet that the pops can be, if not eliminated, at least reduced to acceptable small 'ticks'. It is worth a try.

veckans · 2nd January 2009, 06:25 PM

Quote:

Originally posted by audiosteve
It is hard to know for sure without a schematic, but this board has two multi-turn pots that appear to be for adjusting the output offset (by adjusting the input DC offset). If you measure the DC output and adjust the pots to get the output DC level near zero I will bet that the pops can be, if not eliminated, at least reduced to acceptable small 'ticks'. It is worth a try.

Adjusting the DC offset to +/- 1mV was one of the first things I did when I got this amplifier, I chose it because it had the ability to do that among other things.

audio1st · 2nd January 2009, 07:31 PM

Quote:

Originally posted by veckans
I have also heard that this "pop" noise is caused by the input capacitors charging up, and one way to fix it would be to change to max 2uF capacitors instead of the 470uF that are currently there.

Hi, your input caps are the green 3.6uF items unless you have changed them to 470uF?

veckans · 2nd January 2009, 08:21 PM

Quote:

Originally posted by audio1st

Hi, your input caps are the green 3.6uF items unless you have changed them to 470uF?

I'm sorry, maybe I used the wrong word for them, but by input I mean the DC power input (the 2 smaller electrolytic caps).

v-bro · 8th January 2009, 08:02 PM

I've been told this circuit can be used on ANY Tripath amp to reduce on/off pops to zero.

With credits to Aleka from http://www.41hz.com/forums

EdT · 13th January 2009, 03:57 AM

That looks similar to the PCB on the Pop Pulse Tsunami T-Amp !

v-bro · 13th January 2009, 06:25 AM

Ah ok, I didn't know that thanks! I do know that Aleka had this circuit up and running a long way back, maybe two years?

1st January 2009, 11:45 AM	#1
veckans diyAudio Member Join Date: Nov 2008	Reduce "pop" noise when power on/off I have a Tripath TA2024 amplifier that I really like the sound, and quality of. There is one problem with it however, it produces a "pop" sound when I turn it on/off. It isn't very loud but it ruins the quality feeling. And I'm also told this "pop" can demagnetize speakers after a while, is this true? I have also heard that this "pop" noise is caused by the input capacitors charging up, and one way to fix it would be to change to max 2uF capacitors instead of the 470uF that are currently there. I have measured the DC Offset of this "pop" and it was at most 125mV for one channel, and 90mV on the other. So I wonder how I can fix it cheap. I saw on the charlize (tripath amplifier) info page that you can put the amplifier in "sleep-mode" instead of turning it off by just adding a 260ohm resistor on the input power line (12V). I tried this but the power LED was still on even if dim. The "pop" didn't disappear either, it was just slightly reduced. Thanks for any help!

2nd January 2009, 03:22 PM	#4
audiosteve diyAudio Member Join Date: May 2004 Location: Niwot, CO	It is hard to know for sure without a schematic, but this board has two multi-turn pots that appear to be for adjusting the output offset (by adjusting the input DC offset). If you measure the DC output and adjust the pots to get the output DC level near zero I will bet that the pops can be, if not eliminated, at least reduced to acceptable small 'ticks'. It is worth a try. __________________ Nihilism is best done by professionals.

8th January 2009, 08:02 PM	#8
v-bro diyAudio Member Join Date: May 2006	I've been told this circuit can be used on ANY Tripath amp to reduce on/off pops to zero. With credits to Aleka from http://www.41hz.com/forums __________________ Max. cone displacement can be several foot on any speaker!Too bad it can be done only once......

13th January 2009, 06:25 AM	#10
v-bro diyAudio Member Join Date: May 2006	Ah ok, I didn't know that thanks! I do know that Aleka had this circuit up and running a long way back, maybe two years? __________________ Max. cone displacement can be several foot on any speaker!Too bad it can be done only once......

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2nd January 2009, 07:01 AM	#2
hoka diyAudio Member Join Date: Feb 2008	wich one do you have? can you post a picture? the 470uF caps are most likely not the input caps

2nd January 2009, 10:46 AM	#3
veckans diyAudio Member Join Date: Nov 2008	This is how the PCB looks: But, now I tried "sleep-mode" with a higher ohm resistor (330ohm this time) and for some reason the "pop" is very faint now, and non-existant on turn off, something I can live with

13th January 2009, 03:57 AM	#9
EdT diyAudio Member Join Date: Dec 2006	That looks similar to the PCB on the Pop Pulse Tsunami T-Amp !

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