car stereo head unit nasty distortion suddenly started happening for no reason

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I was just casually playing with the left and right balance on my car stereo head unit and OW MY EARS just SCREECHING LOUD NASTY distortion suddenly started happening. i turned it down immediately but it didnt matter. my car stereo now always does this when i turn it up too loud. and its not normal distortion either. its loud nasty screechy sounding distortion.

I have an audio sample what it sounds like below

Any idea why it could of started doing this? all i did was turn the balance to my left speaker with my volume up pretty high and it just suddenly INSTANTLY without any warning started sounding horrible.
if i turn the balance fully to the right speaker instead of the left speaker. its perfectly fine all the way to max volume (40 on this car stereo)

my stereo is model XDM16BT (DUAL brand)

it sounds horrible like its shorting out or something.
and it only happens above a certain volume. close to max volume (max clean volume is about 31 but its started doing the nasty distorting sound around 28 to 29 now and it gets much worse at 31 and above. its so incredibly screechy and nails on chalkboard sounding

ive had it for a few weeks only. its not overheating because it does it the second i turn it on after its been turned off and stone cold.
it only just now started doing this
 

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Not enough information there to encourage advice!

It sounds like "motorboating" which is not so common these days. Without more details about cabling and installation .....

Everything works until it doesn't, so i don't know how much notice or warning you are expecting it to give you!
 
Try googling "amplifier motorboating" for some hints.

How about a photo of the wiring and connections you have used?

Has it ever worked? In a car? What is the battery voltage? Does it fall when the problem appears?

What have you done so far to isolate the problem? What test gear do you have?
 
It has never been used in a car. I just have it hooked up to a 12v 5AH SLA AGM battery that I keep on a float charger at a stable 13.8v

When it does this noise. the current decreases. it draws less current than it used to before it started doing this. at max volume it would draw about 4 amps. now it only draws about 1 to 3 and it sounds absolutely horrifically awful

it did NOT do this until yesterday. its not being overdriven. it worked fine before yesterday. i could go up to volume 31 and it would be perfectly clean. above 31 it would distort/clip softly quietly. not loud screeching noises like its doing now. and it does it at only volume 30 now

It doesnt happen if i set the L/R balance fully to the right. but it does happen if its at the center or fully left. so something with the left channel is causing it. but ive checked and the rear channel wires are isolated with heatshrink and electrical tape since i'm not using the rear channels at all.

I dont have bass boost. loud mode. or EQ on. I always keep those off. because my speakers sound perfect with no EQ needed. and this problem occurred SUDDENLY without warning. so its some kind of failure in the amp. or some kind of protection or something of some kind.

its like a really sharp clipping screeching (not squealing more like extremely sharp nasty clipping sounding) nails on chalkboard kind of staticy distortion.

https://www.diyaudio.com/forums/att...pening-reason-audio-clip-distortion-sound-zip see this is the mp3 showing what happens when i go past volume 29 it gets bad sounding.

I have the yellow and red wire hooked together running straight to the battery with spade terminals. and the black wire running straight to the battery with spade terminals crimped and heat shrinked on the both wires connected to the battery

all other wires are isolated with heatshrink and electrical tape

i have tried it with/without the charger attached to the battery makes no difference. tried moving the whole setup to a different corner of the house plugged into my phone instead of my computer and it still does it.
 
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the speakers arent the problem. they work fine. ive tried that and its doing the exact same thing.
and because i dont have anything else to plug it into? how else am i going to listen to audio on it? I dont want to be stuck with only using the radio on it
whats wrong with using it with a phone or computer?
 
it doesnt matter if i use the rear outputs bluetooth or USB or by 3.5mm aux cable in phone or computer. i tried all the ways and i cant stand bluetooth or usb flash drive. its just annoying to deal with. i prefer using cable cause i can just plug it into my pc or phone quickly and easily and bluetooth mode makes my speakers have a little bit more hiss when there is quiet sound playing. and also bluetooth mode is annoying too because it cuts in and out for like 0.1 of a second whenever there is a short pause in music or audio. overly aggressive standby in bluetooth stuff is why i generally dont like using bluetooth stuff. i prefer an always active signal
it always does the sound unless to change the balance all the way to the right. and it does the sound in both speakers

and it doesnt matter if i use the rear channels or front channels. same problem. i can have only the right speaker plugged in and it'll still do it if i have the balance set in the middle. but it stops if i change the balance to the right. whether a speaker is plugged into the left channel or not.
 
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rip car stereo. would cost more to fix than just buy a new/better version because it would cost so much to buy the tools to diagnose the problem in the first place. not worth it unless it was a simple obvious fix like replacing an obviously visually burnt/broken faulty component but thats never the only problem.
i'll just see about getting a better amplifier off amazon or something when I can
 
does anyone know why it started doing this? im tearing my hair out trying to figure it out

Hi,
maybe my suggestion coming too late.. : why not check the balance potentiometer!
it could have internal rails broken or dirty with conductive material.. this causing shorting signal at a certain path point... "being lucky" a pot spray lubricant could solve the problem!
 
There is no potentiometers in it at all. it has a single rotary knob on the front. Not a normal potentiometer. all the circuitry is microscopic surface mount stuff and really hard to even get to. it has a million screws holding the display PCB to the front plastic piece.
Ive looked all inside it and it looks absolutely spotlessly clean like it just came out of a clean room.
its gotta be a shorted out or partially broken/burnt component or chip somewhere that has failed in some way.

if I keep the voltage below 13v it doesnt do it hardly at all. but then i get less volume out of my speakers and more normal "distortion"
its so cheap it would cost more to buy circuit cleaner stuff and clean it off than to just buy a whole different/new amplifier or stereo.
 
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oh yes, now I've seen by google what it is on Dual manual.. it is a now-a-day "digital" machine (was thinking about a "vintage" one from an historical brand as Dual is..!), so pot is a "do it all" as by pressing and or touching etc... and of course smd parts inside...
-the lowering voltage supply effect you're referring makes think something bad in a zener diode or a voltage stabilizer, but of course service schematics are needed to troubleshoot problem... and maybe you're right about easier&cheaper look for a new one by a consumer brand.
 
Ive checked all what i can with my multimeter all the larger looking components and im not finding any strange readings on what I "can" check.

I also cant just bypass all the internal circuitry going to the amplifier chip because it requires so many support components to function.
I cant just solder some wires directly to apply power to the amplifier chip, bypass the mute function, and solder an aux cable as close to the chip as I can.
it would be way more trouble than its worth and im running out of soldering wire anyways i need to get some more soon.

my current idea is getting a set of these from amazon
Amazon.com: AOSHIKE 8-25V Dual Chanel HiFi TPA3116 Stereo Digital Audio Amplifier TPA3116D2 Class D Integrated Amp 2.0CH for Full Range Speakers Home Audio System 50Wx 2: Home Audio & Theater
and
Amazon.com: ALITOVE DC 24V 10A 240W Power Supply Adapter Transformer Switch AC 110V / 220V to DC 24V 10amp Universal Regulated Switching Converter for LED Strip Light CCTV Camera Security System Computer Project: Home Audio & Theater to power it.
unless someone can recommend me a similarly priced amp that outputs similar or more power as a single unit rather than requiring a seperate power supply.
 
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Could be 3 faults:

1. The 'jungle IC' (the large chip on the main board with all the audio handling functions in it) took a crap
2. The audio amplifier section blew.
3. Some sort of power supply problem, causing the audio circuitry to get all wonky. For example if the voltage regulation circuits inside aren't working correctly, they could be applying too much or not enough voltage to the internal parts of the board.

Either way it's likely not economical to repair, but if you really want to have a go at it you need an o-scope and DMM at a minimum to see where the signal inside it gets all jacked up. Most of the time you can read the part numbers off the individual chips to see what they are and what they do, just google that part number and pull up a data sheet. Once you figure out which one is involved in carrying the audio signal, you might be able to probe the output pins on it to see if it's providing clean audio. Same goes for the amplifier chip. Problem will be if you do find the problem, can you source a replacement? Sometimes chips are house marked and don't cross to anything you can order on the open market, meaning even if you identify the offending part you might not be able to get another one.

Good luck, I've fixed a couple HU's but the problem was obvious on those.
 
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