"transformers" inside car amp??

Dan2 · 18th May 2008, 10:08 AM

i have a small car amp that i opened up, and found 2 parts that look just like transformers. i just want to know what they are for, 'cos last time i checked, transformers don't work with DC

luka · 18th May 2008, 11:15 AM

Hi

You are right, but there is high freq. choped DC driving trafos, so you have +12v ,0v ,+12v more then 20000x time a second, which is why this are so small compared to 50/60Hz ones. So this trafos do work with AC, which you can get from DC

Dan2 · 18th May 2008, 11:39 AM

are you talking about a SMPS?? cos this is a small chip amp (17Wrms x 4) and doesn't have a smps.

DigitalJunkie · 18th May 2008, 11:49 AM

They're probably filter chokes. Are the in series with the +12V input?

luka · 18th May 2008, 11:49 AM

Hi

Oh ok, in that case I don't know what you mean, I should some pic if you have... Those IC are amps, that don't need nothing else but DC voltage, so no need for smps

Dan2 · 19th May 2008, 08:25 AM

yes they are in series with the 12v input.

so do they filter out the alternator niose??

luka · 19th May 2008, 09:10 AM

Hi

They do a bit, but they are there so that they filter out noise that is comming from amp, so that it doesn't go into car electrical system, it filters both way I guess

EWorkshop1708 · 20th May 2008, 05:33 AM

Quote:

Originally posted by Dan2
are you talking about a SMPS?? cos this is a small chip amp (17Wrms x 4) and doesn't have a smps.

Does your amp have high-level input? (speaker-level)

On some amps i've opened, they all have 2 little transformers on the input side to take the speaker level down to the proper input level. It's a line-level convertor built in the amp for folks with Car stereo's without RCA plugs.

Dan2 · 20th May 2008, 11:13 AM

this does have a high level input, but it has 100R resistors that go to 220k resistors and to the gain pots. these transformers are no where near the inputs.

So i think we have established that they are just noise filters.

thanks guys

EWorkshop1708 · 20th May 2008, 09:43 PM

Input filters..........I don't see that many car amps with them. You must have a good amp, most amps I see have no snubbers or filters.

Glad you figured it out.

What amplifier is it? What IC's does it use to drive the speakers?

18th May 2008, 10:08 AM	#1
Dan2 diyAudio Member Join Date: Sep 2005	"transformers" inside car amp?? i have a small car amp that i opened up, and found 2 parts that look just like transformers. i just want to know what they are for, 'cos last time i checked, transformers don't work with DC

18th May 2008, 11:15 AM	#2
luka diyAudio Member Join Date: Sep 2005 Location: in Slovenia :)	Hi You are right, but there is high freq. choped DC driving trafos, so you have +12v ,0v ,+12v more then 20000x time a second, which is why this are so small compared to 50/60Hz ones. So this trafos do work with AC, which you can get from DC __________________ home page @ http://www.classdaudio.co.cc @ 24/7 all year long I FEEL SLOVENIA

18th May 2008, 11:49 AM	#5
luka diyAudio Member Join Date: Sep 2005 Location: in Slovenia :)	Hi Oh ok, in that case I don't know what you mean, I should some pic if you have... Those IC are amps, that don't need nothing else but DC voltage, so no need for smps __________________ home page @ http://www.classdaudio.co.cc @ 24/7 all year long I FEEL SLOVENIA

19th May 2008, 09:10 AM	#7
luka diyAudio Member Join Date: Sep 2005 Location: in Slovenia :)	Hi They do a bit, but they are there so that they filter out noise that is comming from amp, so that it doesn't go into car electrical system, it filters both way I guess __________________ home page @ http://www.classdaudio.co.cc @ 24/7 all year long I FEEL SLOVENIA

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18th May 2008, 11:39 AM	#3
Dan2 diyAudio Member Join Date: Sep 2005	are you talking about a SMPS?? cos this is a small chip amp (17Wrms x 4) and doesn't have a smps.

18th May 2008, 11:49 AM	#4
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	They're probably filter chokes. Are the in series with the +12V input?

19th May 2008, 08:25 AM	#6
Dan2 diyAudio Member Join Date: Sep 2005	yes they are in series with the 12v input. so do they filter out the alternator niose??

20th May 2008, 11:13 AM	#9
Dan2 diyAudio Member Join Date: Sep 2005	this does have a high level input, but it has 100R resistors that go to 220k resistors and to the gain pots. these transformers are no where near the inputs. So i think we have established that they are just noise filters. thanks guys

20th May 2008, 09:43 PM	#10
EWorkshop1708 diyAudio Member Join Date: Nov 2004 Location: Florida	Input filters..........I don't see that many car amps with them. You must have a good amp, most amps I see have no snubbers or filters. Glad you figured it out. What amplifier is it? What IC's does it use to drive the speakers?

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