hi all,
ive just built a 4x22watt car amplifier based on TDA1554Q amp.
i use 2 of them to make a 22watt x 4channels amp, each one is
totally separated from the other, so each has its own filter cap.
ouputs...etc
http://www.aaroncake.net/circuits/amp20w.htm
its just so simple amp. to drive 2 coaxials and 2 tweeters..
the input is from a battery powered discman,
the prob. is iget that engine whine when car is running,, its
really annoying and mess the whole thing!
am powering the amp. with a 10 or 8gauge "dont exactly remember" power cable, its more than enough as the max. current demand for the whole amp. is about 10A, i tried many diff.
ground locations in the car but nothing works ,the same prob.
the power and the speaker cables arent close and running in diff.
directions so itsnt making probs.
so anything to do about it? try to increase the power filter capacitance or doesnt has effects?! ,am ready to build any good
noise filter if its the only solution...
so i really need any help in this as much as anyone can!
thanks alot..
ive just built a 4x22watt car amplifier based on TDA1554Q amp.
i use 2 of them to make a 22watt x 4channels amp, each one is
totally separated from the other, so each has its own filter cap.
ouputs...etc
http://www.aaroncake.net/circuits/amp20w.htm
its just so simple amp. to drive 2 coaxials and 2 tweeters..
the input is from a battery powered discman,
the prob. is iget that engine whine when car is running,, its
really annoying and mess the whole thing!
am powering the amp. with a 10 or 8gauge "dont exactly remember" power cable, its more than enough as the max. current demand for the whole amp. is about 10A, i tried many diff.
ground locations in the car but nothing works ,the same prob.
the power and the speaker cables arent close and running in diff.
directions so itsnt making probs.
so anything to do about it? try to increase the power filter capacitance or doesnt has effects?! ,am ready to build any good
noise filter if its the only solution...
so i really need any help in this as much as anyone can!
thanks alot..
It's very likely a ground loop. You need to find out where your car stereo is grounded and ground the amp at the same place. Even a few feet away will create whine. It can be difficult to sort the grounds out, but once you do it almost always gets rid of the noise.
You might also try isolation transformers (ground loop isolators) between your car stereo and the inputs to the power amplifier. The people that sell car stereo accessories sell them. MCM Electronics here in the USA has them for about $9.
Some other options are to try to get rid of the alternator noise at the source--the alternator. Some people put filters or large capacitors (10,000uf 25v) right at the alternator output terminal. But be careful of creating a fire hazard if there is a short or failure. But this usually only reduces the whine and never gets rid of it completely.
Higher power car amps are less prone to this problem because they have a DC-DC converter in their power supply so the amplifier ground can be somewhat isolated from the car's 12 volt ground. But in a bridged amplifier like you're using, you have no isolation.
You might also try isolation transformers (ground loop isolators) between your car stereo and the inputs to the power amplifier. The people that sell car stereo accessories sell them. MCM Electronics here in the USA has them for about $9.
Some other options are to try to get rid of the alternator noise at the source--the alternator. Some people put filters or large capacitors (10,000uf 25v) right at the alternator output terminal. But be careful of creating a fire hazard if there is a short or failure. But this usually only reduces the whine and never gets rid of it completely.
Higher power car amps are less prone to this problem because they have a DC-DC converter in their power supply so the amplifier ground can be somewhat isolated from the car's 12 volt ground. But in a bridged amplifier like you're using, you have no isolation.
nw_avphile said:
idont have a car stereo right now,, i use my battery powered discman as an input to the amplifier, i tried to power ground the amp. to diff. locations in the car but with no use...
anyway, ive a 2x 10,000uF 25V. caps right here, but can i use them b4 the power input of the amp. instead of putting them after the alternator output?
and what about using or even building a good noise filter? dont know any about em but can learn!
thanks in advance..
Do you have the +12 input connected to the battery or some where else? It sounds like you may have alternator noise. The best way to get rid of it is to connect both + and ground of the amp directly to the battery. If the noise is still there add a choke to the + wire as close to the amp as possible. You will need a power switch to turn the amp on and off.
Good luck
BZ
Good luck
BZ
HDTVman said:
i already tried many diff. locations for grounding...1st the power cables were connected to the battery + & - terminals, theni tried to ground to a more near points , like where my old HU were grounded, then to one of the doors, seats....etc the same prob.
and the amp. already has a ON/OFF switch...
so any other ideas?
Deep Anger,
Yes, you need to build a filter. It is the same filter as a crossover filter. I don't know the exact values. From the battery wire (before your amp) an inductor. Then a big capacitor from + to - then a .1uF cap in parallel with that. Then another inductor inline with the ground, followed by a .1uF cap across the + and - then a big cap from + to - make these in series as the position of the inductors with the caps is important. If you want, experiment with a low pass filter, as in a speaker box. A simple inductor (iron core) and a capacitor from coil to ground. With 10,000uF caps, the inductor can be fairly small, possibly air core. Experiment and see! Put one on each power lead at different times, you may find the noise on the ground lead! you may want to put a filter on both of the leads. Are you using batteries or power for the diskman? That is probably where the loop is being formed. Hook up the amp, by itself and see if the niose goes away or goes down in volume. If so, the diskman is the problem. If not, filter the amp.
Hope this helps,
Chris
Yes, you need to build a filter. It is the same filter as a crossover filter. I don't know the exact values. From the battery wire (before your amp) an inductor. Then a big capacitor from + to - then a .1uF cap in parallel with that. Then another inductor inline with the ground, followed by a .1uF cap across the + and - then a big cap from + to - make these in series as the position of the inductors with the caps is important. If you want, experiment with a low pass filter, as in a speaker box. A simple inductor (iron core) and a capacitor from coil to ground. With 10,000uF caps, the inductor can be fairly small, possibly air core. Experiment and see! Put one on each power lead at different times, you may find the noise on the ground lead! you may want to put a filter on both of the leads. Are you using batteries or power for the diskman? That is probably where the loop is being formed. Hook up the amp, by itself and see if the niose goes away or goes down in volume. If so, the diskman is the problem. If not, filter the amp.
Hope this helps,
Chris
since you are only drawing 10a you can just make a circuit usign a 12v regulator to regulate the 14v down to 12. this should reduce the noise quite a bit. an independant power source will always solve the problem, and in other cars ive worked in (that had an inverter as well), we would just use ac-dc wall transformers laying around and use them...always worked
good luck
-chris
good luck
-chris
You can probably buy a ready-made noise filter (made in China) much cheaper than you could build one. They make them in various ratings up to at least 40 amps which is more than you need for your amp.
It might also be you have a grounding problem within the amplifier. If the grounding is done wrong it will destroy something known as the Common Mode Rejection of the amplifer. This is basically the amp's ability to reject power supply noise (like alternator whine).
It's very important to use a "star" ground for all the critical grounds. Especially critical are the input grounds, any of the input circuitry grounds, and the feedback loop grounds (i.e. the dc blocking capacitor to ground in the feedback loop). All of those grounds should tie to a common SINGLE point like the center of a "*".
Grounding can be tricky and sometimes it's a matter of trial and error to find the problem.
It might also be you have a grounding problem within the amplifier. If the grounding is done wrong it will destroy something known as the Common Mode Rejection of the amplifer. This is basically the amp's ability to reject power supply noise (like alternator whine).
It's very important to use a "star" ground for all the critical grounds. Especially critical are the input grounds, any of the input circuitry grounds, and the feedback loop grounds (i.e. the dc blocking capacitor to ground in the feedback loop). All of those grounds should tie to a common SINGLE point like the center of a "*".
Grounding can be tricky and sometimes it's a matter of trial and error to find the problem.
heey guys! ive a good news 
...
when i putted a one 10,000uF 50V. cap. across the power input
of the amplifier, the whine noise has been reduced to about 50%
whats really great as a beggining!!, so what now?!
should i increase the capacitance and expect a more satisfying
reduction in the noise?! , or ineed more elements to build a good
noise filter!?
thanks again..
waiting for ur valuable replys!
...when i putted a one 10,000uF 50V. cap. across the power input
of the amplifier, the whine noise has been reduced to about 50%
whats really great as a beggining!!, so what now?!
should i increase the capacitance and expect a more satisfying
reduction in the noise?! , or ineed more elements to build a good
noise filter!?
thanks again..
waiting for ur valuable replys!
I don't know if Egypt is on metric or not but get a 10mm steel bolt and wind about 50 turns on it and put it inline with the posative pole then the cap across as you have it.... I'll bet you get even less whine then!!!!! Put more turns as necessary and I'll bet it all goes away!!!! Try it out and let us know.
Chris
Chris
You are just applying a bandaid to your problem with the capacitors / filter section you are thinking of adding. The normal fix of alternator whine is caused by a difference in ground potential between the source and the amplifier. In your case, your HU has a floating ground since you are running it off batteries, and therefore it has a different ground entirely from your amplifier. You can run a ground wire from your source (portable CD player) to the ground of your amp. Or you can buy a ground loop eliminator (which does the same thing as the previous method, it just connects the grounds through the shielding of the RCA's). Either way, the capacitor you installed is only a bandaid covering the underlying problem, but doing nothing to fix it.
Good News!
thanks God, it has been solved in two way:
1- itried to power the discman from a universal cigarette light
9V. adapter (diy one) ,and yes the whine sound has totally gone!
,about the reason , its simply caz of connecting all grounds of the
whole system (discman,amp....etc) to the same point... its the
same thing as (Mach_Y) mentioned before! thanks man...
2- ive built this simple diagram consisting of 2x 10,000uF caps.
and one inductor (50turns of thin insulated wire around a steel
bolt) and its also eleminated the noise completelY, as u mentiond
before (Doide)..thanks so much,, but the most imp. part is why?
this circuit IMHO works to purify the pulsating DC (due to noise)
to make the output more linear DC, am i right?? or i mess something?...
anyway, am really thankful for ur help all!!
thanks God, it has been solved in two way:
1- itried to power the discman from a universal cigarette light
9V. adapter (diy one) ,and yes the whine sound has totally gone!
,about the reason , its simply caz of connecting all grounds of the
whole system (discman,amp....etc) to the same point... its the
same thing as (Mach_Y) mentioned before! thanks man...
2- ive built this simple diagram consisting of 2x 10,000uF caps.
and one inductor (50turns of thin insulated wire around a steel
bolt) and its also eleminated the noise completelY, as u mentiond
before (Doide)..thanks so much,, but the most imp. part is why?
this circuit IMHO works to purify the pulsating DC (due to noise)
to make the output more linear DC, am i right?? or i mess something?...
anyway, am really thankful for ur help all!!
Attachments
YOWZA!!!!!
Great work! I'm glad to hear it because I have had many problems in the past also. No one ever told me to star ground everything! I just had to bruit force it with heavy noise filters. As the filter goes, you are simply smoothing the ripple like after an AC bridge rectifier, just at a different frequency, that's all.
Anyway, Thanks for telling us about your success and what you did....
You are welcome!
Chris
Great work! I'm glad to hear it because I have had many problems in the past also. No one ever told me to star ground everything! I just had to bruit force it with heavy noise filters. As the filter goes, you are simply smoothing the ripple like after an AC bridge rectifier, just at a different frequency, that's all.
Anyway, Thanks for telling us about your success and what you did....
You are welcome!
Chris
There is no need to star ground things in a car. If all the grounds are connected to the chassis, the chassis provides a much better bus (like a .01 gauge cable) than a long cable of 4 guage running to a common ground. You just need to make sure everything is grounded to the chassis.
I've heard plenty of engine whine, none of which couldn't be eliminated with good grounding and separated power/signal cables.
I currently have my power/signal cables running next to each other because of installation ease, but the signal cables are triple shielded and have a ground wire with them, which I connected to the deck and one of the screws into the chassis from my amp. I couldn't hear any engine noise without the ground but it didn't hurt to use it in my case.
To test for engine noise, even the slightest, get a BLANK recording, turn volume all the way up, and drive around. Rev the engine to fairly high rpm. Even a small amount can be very annoying.
I've heard plenty of engine whine, none of which couldn't be eliminated with good grounding and separated power/signal cables.
I currently have my power/signal cables running next to each other because of installation ease, but the signal cables are triple shielded and have a ground wire with them, which I connected to the deck and one of the screws into the chassis from my amp. I couldn't hear any engine noise without the ground but it didn't hurt to use it in my case.
To test for engine noise, even the slightest, get a BLANK recording, turn volume all the way up, and drive around. Rev the engine to fairly high rpm. Even a small amount can be very annoying.
alternator whine wont go
I need some help. the car is a OPEL Corsa Sail. A 1.6 liter hatchback.
http://www.automandi.com/Content/new/Opel Corsa Sail.asp
http://www.reachouthyderabad.com/business/biznews/gm2.htm
My stereo consists of the following.
1 x blaupunkt car stereo (tape)
2 x blaupunkt 4 channel power amps (8 channels total)
2 pairs of Vifa 2way (front door and rear deck)
1 pairs of Blaupunkt Velocity coax (rear pods)
1 pair of Vifa 6" woofer (rear deck)
the first power amp feeds the front speakers and the rear speakers (Vifa 2 way). the second power amp feeds 2 Vifa 6" woofers and 2 4" Blaupunkt Velocity full ranges that are also in the rear. both the amps are mounted on the rear of the rear seat.
The amps and the head unit are grounded to the chassis albeit the head unit is the front and the amp in the rear.
the power wires run on the drivers side of the car and the RCA wires from the headunit run from the passenger side of the car.
I get very pronounced alternator whine. If I use the tapedeck without the power amps (using only 2 pairs of speakers) the whine is gone. that is if i use the speaker outs on the tapedeck direct to the speakers (no amps) the whine is gone. if i use the rca out and if i connect even one amp (any one amp) and only connect 1 pair of speakers the whine is back.
I am using reasonably high quality RCA wire.
any solutions.
I need some help. the car is a OPEL Corsa Sail. A 1.6 liter hatchback.
http://www.automandi.com/Content/new/Opel Corsa Sail.asp
http://www.reachouthyderabad.com/business/biznews/gm2.htm
My stereo consists of the following.
1 x blaupunkt car stereo (tape)
2 x blaupunkt 4 channel power amps (8 channels total)
2 pairs of Vifa 2way (front door and rear deck)
1 pairs of Blaupunkt Velocity coax (rear pods)
1 pair of Vifa 6" woofer (rear deck)
the first power amp feeds the front speakers and the rear speakers (Vifa 2 way). the second power amp feeds 2 Vifa 6" woofers and 2 4" Blaupunkt Velocity full ranges that are also in the rear. both the amps are mounted on the rear of the rear seat.
The amps and the head unit are grounded to the chassis albeit the head unit is the front and the amp in the rear.
the power wires run on the drivers side of the car and the RCA wires from the headunit run from the passenger side of the car.
I get very pronounced alternator whine. If I use the tapedeck without the power amps (using only 2 pairs of speakers) the whine is gone. that is if i use the speaker outs on the tapedeck direct to the speakers (no amps) the whine is gone. if i use the rca out and if i connect even one amp (any one amp) and only connect 1 pair of speakers the whine is back.
I am using reasonably high quality RCA wire.
any solutions.
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