Have you heard these speakers with an enclosure in your home? As they are intended for car applications, I think you will be disapointed of the sound in your home. In the car bass is boosted and higher frequencies absorb. At home I suspect them to sound thin and forward. I guess the speakers drop to about 3 ohm, a heavy load for a single LM3886. If you want really balanced sound in your home there are better suited speakers.
I want to use those for satellite speakers in 2.1 system
as you all telling me that these are not suitable for home listening but here in my place there are no Hi-Fi full range speakers are not available thats why i have chosen them if you have any idea about Hi-Fi speakers in India please suggest me,here only i can have woofers
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I have no idea of what kind of speakers you have in India. A poweramp based on LM3886 can justify even very good speakers. Unfortunately, low impedance speakers (as car speakers) are not the best match. Three LM3886 in parallel for each channel can do it but it will also call for a bigger poeer supply. A pity, you do not have access to real hifi speakers for home use. What kind of enclosure do you have in mind for the JBL-set?
batteryman,
Whiskey Tango Foxtrot?!
The PCB layout most certainly IS critical, for audio circuits.
And if a schematic is changed, there COULD be a change in sound quality.
The two are independent of each other so your statement makes no sense as a conditional. And the two parts of it are both completely wrong, anyway, as general statements.
I haven't read the rest of the thread so I hope that your intended advice was correct, in this case, even though the way it was said can't stand on its own.
Tom
.
But I never said 'Schematic' you did and this means changing the circuit.
I said 'PCB layout' - this means altering the track routing NOT the schematic.
Small changes in the pcb design are not audible.
BM
To run them in parallel you need well-matched gain-setting resistors as well as a resistor on each chipamp output. It bothers me to see this tossed out without urging readers to carefully and thoroughly read the datasheet and applicable app notes, otherwise you might as well toss these things into a fire.
It depends on where it is - often some areas "aren't so important," but with the LM3886 (or really anything in the "chip amps" forum) most all areas ARE important. There's the full output and power currents going right next to a line-level signal. If the speaker ground current shares a trace with the line-level ground (a "logical" thing for a less-than-fully knowledgeable layout person to do) then it's a bad layout. Read the LM3886 data sheet and related app notes. Read every square inch (or square centimeter/centimetre) of them.
batteryman,
How can you even try to argue? I quoted your post #101 directly.
You said both "layout" and "schematic":
Here's what I quoted from your post:
"The pcb layout is not critical for audio circuits so there won't be any loss of quality if the schematic is not the same as the datasheet."
Also, I disagree with your new statement, because "small changes in PCB design" can be quite audible.
I've said things that made less sense than those, here. But when it's pointed out, I usually try to say something like "Oops! Sorry!". However, if you genuinely disagree, then that's where the fun starts, here (and where things can be learned)!
Anyway, I didn't make that post to attack you! I did it for the benefit of those who might read this thread. (OK, maybe I'm a bit of a stickler about accuracy. But I believe it's important. And I quickly learned, here, the hard way, that we all should be prepared to have to defend what we post, which tends to make us think harder about its accuracy before hitting the Submit button, which isn't a bad thing.)
No worries. Carry on.
Cheers,
Tom
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Hello apexaudio!
I really appreciate all your work and research.
Thanks for posting your work on this forum!!
I have built this module according to your PCB and installed the correct parts on it.
The PSU is 24-0-24V/5A Trafo with 4700uF/50V Capacitors 85 degree types.
When I try to power up the circuit, there is only hum from the speakers... I am using the amp on a 8 ohm load.
I also checked for shorted PCB traces. But everything is fine.
I have used metal film resistors and box type capacitors for the build to induce the least noise.
But this is something else...! The IC gets hot as soon as I switch the amp on.
Is it that there are shorted traces? Or the IC is bad?
Regards
I really appreciate all your work and research.
Thanks for posting your work on this forum!!
I have built this module according to your PCB and installed the correct parts on it.
The PSU is 24-0-24V/5A Trafo with 4700uF/50V Capacitors 85 degree types.
When I try to power up the circuit, there is only hum from the speakers... I am using the amp on a 8 ohm load.
I also checked for shorted PCB traces. But everything is fine.
I have used metal film resistors and box type capacitors for the build to induce the least noise.
But this is something else...! The IC gets hot as soon as I switch the amp on.
Is it that there are shorted traces? Or the IC is bad?
Regards
The back of the IC can not touch metal if that metal is grounded. If you have insulated the back of the chip then you need to also make sure that there is no bolt touching the tab of the chip. Turn it off and use your multimeter to see if you have any resistance/short between ground and chip tab.
Then get a wire and put an alligator clip on each end. Attach one end to earth ground and the other end should then touch signal ground, then speaker ground, then the 0V ground from the secondary side of the transformers. Listen while you do this. Often if its not a cold solder joint you can find the grounding problem this way. Also try one alligator on signal ground then touch all the other grounds then try one alligator 0V and one Earth.
Uriah
Uriah
The transformer wiring seems to be fine according to me.
The signal ground, transformer's middle wire (ground) and the amplifier ground are soldered to each other.
I use a 35A Bridge. The power supply seems to be fine too.
I am just scared to check the DC Offset!! The IC turns so very hot as soon as it is connected even though it is on an heatsink! I just expect that it will burn!
So I'm kinda scared too!!
I still don't know what the problem is! I also checked for shorted traces.
But I din't find any!
I'm confused!!
The Layout of components does not match the schematic.
D2 has to be reversed on the component layout for it to match!
I realized it when I tried to troubleshoot the PCB to find any mismatch in traces and the schematic...
The amp's working smoothly once i reversed the diode!
Also I changed the 15K resistor to 33K to increase the gain...
Thanks for all your help guys!
Regards!