yashsingh1/xdaforums huggingface dataset:
[MTCD  Android Head Units Q&A] kaise123:
I also believe this is related to the inside of the unit having poor power delivery and bad isolation. Unfortunately the audio is all routed on the main PCB itself so it is not easy to isolate it. I did improve things considerably by soldering directly to the output from the BD37534FV controller and then using this as my RCA output. I did try some further digging but wasn't able to trace the source of the noise back any further.

Next I am going to try adding a capacitor to the power supply, removing the built in TDAXXX amp chip and seeing if I can improve the ground connection on the unit.
[MTCD  Android Head Units Q&A] dranet:
Hi.

Finally, I achieved what I wanted more or less, I reduced the number of noises to a minimum, using RCA converters from high to low voltage, adjustable at the expense of the output volume, but I made up for it with the Viper4android module, making listening to music comparable to sitting in a concert hall. Cool effects can be obtained with this module.

That's enough for me, of course, the noise is still present, but it's not as bothersome as before. I do not have the effect anymore that while driving from 100 km / h up, the noise increases and the volume stays constant.

Still, unfortunately, I can not connect anything to the rear USB, because the speakers start to tweet data transmission, similar to the transmission of the modem only faster, I have a USB webcam connected to the front of the radio, unfortunately it is annoying but at least there is no noise.

Of course, to reduce the number of noises in the car completely, I would have to exchange Chinese cheap radio, for which I paid some 300USD for some better, eg from Xtrons radio, they are supposedly better done, but I would have to play with 2DIN frames and it will not be anymore perfectly fit in place of the old radio.

Thanks

DD
[MTCD  Android Head Units Q&A] Xorit:
This is what I use:

ESX High-To-Low Level Converter ISC4

or

HIFONICS HCV4
[MTCD  Android Head Units Q&A] zefirz:
[MENTION=2857274]dranet[/MENTION]

can you share the links of the Hi-Lo converter as well as the cables you bought?
[MTCD  Android Head Units Q&A] dranet:
Hi

I bought the converters at the allegro.pl Polish auction.

When you buy, it's important that you have the ability to control the RCA signal level so that you can drive the signal to the right level.

I bought the triple shielded cables, but the signal for the Bose amplifier has been released for the time being with original cables.

Later, I can actually put on RCA cables so that there are even less disruptions :)

https://allegro.pl/konwerter-poziom...kZTFhNWJjNThhNTNmNmU3MjZjNzMyMDVhMDZhN2JmZTI=

https://centrumaudio.pl/kable-sygna...nocar.html?search_query=kabel+4xrca&results=8
[MTCD  Android Head Units Q&A] Andskomar:
Do you have a head unit with a built-in dsp?

I have a radio from androidautoshop with a built-in dsp (it also suffers from noise
[MTCD  Android Head Units Q&A] Octane70:
From my research, they all do. Just cheap components. You need to try and tune it out either with hi/lo level converters with gain control, or external crossover/line driver which i use. I successfully tuned out the "static" noise.
[MTCD  Android Head Units Q&A] brand24:
has anyone found a solution to this issue?

I am having this same problem and I simply can not find a fix other than to purchase a quality brand name such as Alpine or Pioneer?

Video of sound below

https://www.youtube.com/watch?v=0vhT7AavZbg
[MTCD  Android Head Units Q&A] mikemat.pl:
Hello, have you found a solution, how you fix noise ?
[MTCD  Android Head Units Q&A] rafc02:
I was having noise on the RCAs related to the lcd as well. I was able to almost eliminate it completely by turn the gain on the aftermarket amp close to all the way down. To compensate for the lower volume output, I went into the factory settings and turned the 'System' volume bias up (around +11 in my case).

If you're connecting the RCAs to a factory amp, you may not have the ability to adjust the gain - but maybe this will help those with aftermarket amps.
[MTCD  Android Head Units Q&A] UltraMagnus0001:
I have a PX5 Pumkin and also and a home TDA amp with Bluetooth. The interference is from the Bluetooth for me, because the PX5 and the home amp both make noises with the Bluetooth on. With the PX5 the hiss is there, but when the Bluetooth is on you can hear the beeps and tones of the data like an old dial up modem or an 8bit video game sound effect. The interference is definitely internal to the radio and not from the audio cables. To test the cables unplug it from the PX5 or the Amp to narrow the noise down. I have extra grounds and my power for the car is on the right while the audio is on the left. The can bus cables are not inrerfereing with the audio cables either.
[MTCD  Android Head Units Q&A] julien_blanche:
Hi,

to anyone having static noise from the head units, it is not related with the amplifier chip inside totally, it is about the low quality parts and low 2000-3000 uf input filter capacitor that used. If you make a cheap and effective upgrade in terms of suppressing static noise and sound quality do the followings;

1- Replace input filter capacitor of the head unit with 10.000uf Japanese brand may be rubycon or nichicon (this will give you more power deep bass and effective filter for DC ripples)

2- Clean power feed to your head unit if your power connected more than one devices it is nor recommended

3- Clean and short groundings can improve audio considerably

4- Do not spend money for products about noise suppressor or hum eliminating or line converter etc...they are all useless most of the time

5- I have tried a couple android head units and joying with coax(digital) out is the yet best on the market with 2.4v RCA outs distortion free and clean without hiss sound

6- Also if you are using the external power amplifier try lowering the gains hence static noise rises if you turn up gain too much

7- Since you are using the regular android head unit and most probably its putting 0.4v RCA voltage and you are turning up gain to match amp-head unit that creates the hiss

Also bear in mind that, some degree of static noise will be coming always through your tweeters. I have a $ 50k audio setup at my home and some quality equipment in my car, if you listen closely the tweeters you can hear static noise. Normally it should be heard from 1 feet and it is acceptable at normal volumes but you are sitting in car close to tweeters so it may be acceptable.

But the source of the static sound is 12.000 hz and above, if you are very uncomfortable about the noise then you can lower the frequencies above 12.000 hz and you will notice immediately that noise is gone.

Also do not bother about lowering 12k hz frequencies in the equalizer hence most of us is not hearing these sounds, when you get older this hearing limit lowers also :)

Those are the first things to do in terms of clean audio, list could be extended but not needed since you are sitting non-acoustical environment,

hope it helps,

cheers.
[MTCD  Android Head Units Q&A] superkekko:
[YOUTUBE]https://youtu.be/y94gl8Oz1Go[/YOUTUBE]

my usb on px5 .

same problem
[MTCD  Android Head Units Q&A] DieselManiac:
Did you manage to resolve this RCA issue?

The capacitor might be a problem it's from the brand ChongX on most units and does have a lower value than specified.

And a lot of fake components (transistors) on the board, did you rework a headunit?

I will start with replacing the capacitor and the transistors in the signal path.
[MTCD  Android Head Units Q&A] lefterisa3:
I am dealing with this high pitched static noise for months.. i soldered rca output directly on the bd37534 chip after the decoupling capacitors. Rca ground on board ground point and i have finaly got rid of the noise.

The output is low. Close to 1.3volt playing a 0db 1khz test tone .

I use an external audison bit ten dsp so signal was usable. Together with wadzio moded mcu and it sounds much much better now.

If anyone try this make sure you get the signal right after the capacitors to get rid of any dc voltage present.

Ps.. and no more noise when pluging anything to the usb port..
[MTCD  Android Head Units Q&A] UltraMagnus0001:
Most of the noise for me is from the Bluetooth trying to connect. After driving for a few minutes the noises will go away. When I have my phone connected, every once in a while the noise kicks in and goes away with wifi searches. My noises are clicking and screeching as if a dial up modem is connecting, but lower. I have almost no Ignition or ground loop noises except for a hiss and the Bluetooth noises. I have 2 external amps, 1 Alpine for a sub and a Rockville for the rest. My gains on the amps are low and the head unit is definitely the noise maker, because I can definitely tell when the outputs turn on the head unit. You should also pay attention which side you run your audio and power cables in your vehicle, because I swapped mine around from side to side and my ignition noises iare almost gone except at high volumes.
[MTCD  Android Head Units Q&A] doktor29:
hello

i have a px5 unit with 4gb ram, android 9

when listening radio i have something like "no sound" every 10s (around)

somebody have this issue and how to fix ?
[MTCD  Android Head Units Q&A] DieselManiac:
This is the beste solution if heard!

Thank you very much!
[MTCD  Android Head Units Q&A] An92:
[MENTION=2287433]julien_blanche[/MENTION] [MENTION=8426842]lefterisa3[/MENTION] [MENTION=10775045]DieselManiac[/MENTION]

Hi friends, I have a mtce px3 unit, 7.1 mcu kld no dsp, amp internal chip is tda7851L

I have always had problems with slight noise with a volume greater than 0.

The most annoying thing is to hear a hum (in addition to the basic one) when I have the USB dashcam activated, or in general when I use the USB ports.

I installed the modified widzio mcu, the sound has improved but the noise is always present ..

I use the classic outputs, the power supply and socket from the original connector (original I have sony ford radio), NO RCA audio, on my modest system with mixed pioneer and sony speakers (without additional amplifier), they are not perfect but I'm happy, except that for this bad noise on usb that makes me crazy for 2 years, I tried to connect the ground from the chassis of the unit, power filter, nothing.

Thanks to you I discovered this method, cheap and fast.

I would like to replace the 3300uf capacitor (

ChongX) with a 10,000uf good quality one

1- I can only do this modification of the capacitor if I use classic outputs, no rca ??

I believe I could not damage the unit.

If I have translated well, the rca output is always powered by low voltage and also creates this disturbance, possibly I could disconnect this output in some way, or I just need to replace the 10,000uf capacitor only and leave the rca powered ??

Original capacitor is 3300uf 25v, what the 10000uf volt??

Could you fix with condensatorat the noise when using usb, because i not use rca output ??

Thanks very much
[MTCD  Android Head Units Q&A] DieselManiac:
25v is fine, please don't buy it in China it's most of the time fake, i bougth this one: https://www.ebay.com/itm/10000uF-25V-105C-Radial-Electrolytic-Capacitor-Nichicon-UVZ1E103MRD/111660233476?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I have no noise when connecting to the speaker cabels only on the RCA's I will try the RCA solution this weekend and will post the solution if the noise is gone.
[MTCD  Android Head Units Q&A] An92:
I just need to replace the capacitor ?? I don't use rca outputs

The dimension of your product link is same of the original??
[MTCD  Android Head Units Q&A] An92:
[MENTION=10775045]DieselManiac[/MENTION]

I am looking for a 10000uf capacitor but I noticed that they are necessarily bigger ChongX 3300uf 12mm, 10000uf is 18mm, as in the photo, I have no space, according to you how can I fix the new capacitor ??

Do I have to mount a smaller one or can I use thermal sheath ??
[MTCD  Android Head Units Q&A] marchnz:
Id start by removing the glue that can be seen in the photo. Use isopropyl alcohol.

All around the power amplifier as well. The glue is known to become resistive over time and cause all sorts of problems.

A higher value capacitor, which will also be dimensionally larger, can be installed by bending it down onto the board before soldering.
[MTCD  Android Head Units Q&A] An92:
* Thanks for the advice, my fear is that the external metal part of the bent capacitor could short circuit on the board??

I can put the connection pins of the capacitor in tight thermal sheaths

* Is there anyway the possibility that the tda 7851l amplifier originally mounted is a good Chinese clone, like the 3300uf capacitor ??

Thanks friends
[MTCD  Android Head Units Q&A] An92:
Update ... I tried to replace the capacitor with a 10000uf coupon, the noise while USB usage increased, I returned to the original capacitor, which is unfortunate

I can't solve it in any way.

Is there a possibility that Chinese radios mount clones of tda 7851l, since there are many Chinese clones of this chip or others ??
[MTCD  Android Head Units Q&A] An92:
I have important news.

I tried to connect the dashcam usb by connecting only the 2 data PINs on the rear usb port of the unit, and instead the + is - (power supply) of the dashcam usb on a charger for 12v cigarette socket of the car, and also on the front usb port , everything works, the loud rustling that was heard when I used USB devices connected to the unit and almost gone, the minimal rustling that this unit has

Finally!!!!

Now I have some SOLUTIONS, I would like help from you to choose the best one.

My chip that manages USB on my px3 klyde mtcd / e unit is a gl850g, model HH 28 PIN rectangle (NO square)

Where can I get the PIN + and - of the usb ports ??

Hypothesis 1:

I take from the front USB port, connecting in parallel the 3 ports, 1 front and 2 rear, but I am afraid that by connecting multiple devices something could burn.

Hypothesis 2:

I buy a 12v to 5 volt transformer and connect the +/- here, I take the current from the machine, but I would like everything to work when the radio is on, so it is born:

Hypothesis 3:

I find 5v voltage on the unit's mtcd and connect the rear USB port PINs here, maybe it could increase the noise, or

Hypothesis 4:

I find 12v voltage on mtcd of the unit able to maintain the current for the 12v-5v transformer, and from there bring current to rear usb ports bypassing the original power line of the usb ports, but also here it could increase the noise around the audio unit

Can you advise me, thank you
[MTCD  Android Head Units Q&A] marchnz:
If others had success increasing the value of the main reservoir capacitor, it may be a coinicidence, or there noise might have been car generated, entering the head unit.

The issue is poor design; lack of power-supply decoupling and internal noise suppression. Internally generated noise enters the audio path. Another issue is liberal use of glue which becomes slightly conductive with age. Ive mentioned both of these a number of time now.

No software upgrade will solve this. It is a hardware design issue.

What you might try, is adding 0.1uf capacitors , on the supply lines, close to the various noise sources, such as the usb hub.
[MTCD  Android Head Units Q&A] An92:
I am purchasing a module that transforms 12v-5v (2A) where I connect the power supply of USB devices in parallel, and only the data signals arrive at the unit without asking for power ... I did not quite understand where to put the 0.1uf capacitors
[MTCD  Android Head Units Q&A] UltraMagnus0001:
Digital signals from the Bluetooth and WiFi causes the interference for me. I can hear the noises when they're trying to connect. When I'm connecting my phone to car leaving for work in the morning via Bluetooth I hear the noises like a dial up modem and when I arrive to work or home with the WiFi trying to connect makes clicking noises.
[MTCD  Android Head Units Q&A] dape16:
How many tried a hi-low converter instead of using the head units RCA-outputs to an amplifier, and did you notice any difference in hiss and noise?

It feels like every component in the head unit is interfering with the sound. Wifi, USB-connectors, screen... I understand this must be a hardware related problem, and different ROMs does not make any difference.
[MTCD  Android Head Units Q&A] ijaz khan:
Android headunit

I had same problem. Tried turning off bluetooth worked for me. The weird hiss sound is gone now. But if i turn on bluetooth it comes back.
[MTCD  Android Head Units Q&A] marchnz:
Suggest using an oscilloscope and start poking around. You won't find it without one and software won't help.
[MTCD  Android Head Units Q&A] MarcoOSX1976:
Hello, could you please tell me why you connect also the front usb port? I tried to do the same but the usb dosen't work. I connected the power to the usb rear cable and the data cable on the unit but i have only power from the usb no device can be found from head unit.

Thanks
[MTCD  Android Head Units Q&A] talrhv:
hi guys,

can this help with background noise that is coming out from the head unit subwoofer rca cable?

I have a subwoofer with amplifier that is connected and I concluded that the noise is coming out from the head unit rca (dasaita px6 head unit).

View attachment 5203495
[MTCD  Android Head Units Q&A] UltraMagnus0001:
I don't know what that is, but the noise most likely is internal to the px5 and that seems to be an external device to block external noises. Is that a noise isolator for the radio harness?
[MTCD  Android Head Units Q&A] talrhv:
Yes I think so. My unit is px6. How can I fix or reduce the noise that coming from the rca? Thanks.

It sound like “tik tik tik tik tik” about 3 per second.
[MTCD  Android Head Units Q&A] UltraMagnus0001:
If it's coming from the RCA, try moving it to the other side of the vehicle. It' helped on my Mazda5. Try turning off or not connecting to Bluetooth on the unit see if the noise goes away. On newer vehicles 2000 up, the CAN and other communication systems can cause interference to audio equipment, that's why they twist those wires. They'll usually run one type of harnesson one side and another on the other side to prevent problems. On some older BMWs they actually ran optical wires to prevent interference for the audio system or airbag systems and then found out the optical plastics would deteriorate over time.
[MTCD  Android Head Units Q&A] talrhv:
I tried to ran a new rca cable in the middle of the car just to see if it is caused by electric wires and the result was the same.

my original rca is going from the right side panel and the power and remote control are going from the left side.
[MTCD  Android Head Units Q&A] Bob_Sanders:
That device is just a larger capacitive reservoir to smooth out the input voltage and will not help the ticking. The ticking is interference which is coming from within the head unit itself.

Some people have had success in connecting the head unit's SPEAKER wires to the rca inputs of the amps. You can try that. You can also try turning off your wifi and bluetooth and see if that does anything to the noise. The only other thing you can do is turn down the input gain on the amplifiers (if you have gain adjustments on your amps) but it will be at the expense of some overall volume of your amplifiers.

Honestly though, this noise problem has been an issue for a number of years now and no one that I know of has been able to figure out EXACTLY where it is coming from, and how to stop it. The best I have seen people do is MASK the noise in various ways
[MTCD  Android Head Units Q&A] DieselManiac:
I found a way to get rid of this noise on the RCA's.

I made a direct connection with de DSP chip afther the decoupling capacitor.

I think that this will work for all the android headunits, the layout of the PCB's is almost identical.
[MTCD  Android Head Units Q&A] Bob_Sanders:
Well... not quite the same (px6 max 10), but I do understand what you have done. I can figure it out by back following the input pins on the amp chip. Did you cut the traces to the amplifier chip or just leave them? How is the volume output?

View attachment 5207635
[MTCD  Android Head Units Q&A] marchnz:
You should add additional decoupling caps or remove power amp/cut trace.

Also, use shielded audio cable.
[MTCD  Android Head Units Q&A] DieselManiac:
I didn't cut the traces, the output volume is perfect. Look for the audio/dsp chip and look for the pinout. Find the decoupling capacitor and solder the RCA wire on it and you will be happy.
[MTCD  Android Head Units Q&A] talrhv:
Thanks for sharing this.

can you attach photos of the other side where the cables goes to?

I don't really know much about soldering but I believe that I can figure it out.

I have good hands with small devices (fixed lots of iphones and android phones in the past). Thanks!
[MTCD  Android Head Units Q&A] Bob_Sanders:
They go to rca plugs, so you can plug into external amps.
[MTCD  Android Head Units Q&A] talrhv:
it means that I'll make an alternative rca cable for a subwoofer for instance with this method?

without ticking noise because I'll be making a better grounding?

thanks.
[MTCD  Android Head Units Q&A] marchnz:
Depends on how better the ground is :)
[MTCD  Android Head Units Q&A] Shubik:
Hello,

I seem to have a same or related issue with my Mazda CX-5 and a chinese (Mekede brand) head unit. Can you tell me if audio in this video illustrates the same issue? Because I hear not just static, but crackling noises and sometimes loud "tick" noises (not captured on this video)
[P8lite Android Development] XTutorials:
Reserved

Screenshots:

Note: these are not screenshot from the actual device.

Regards,
[P8lite Android Development] XTutorials:
Frequently Asked Questions (F.A.Q)

1:

Q.Is this ROM stable enough to be my daily driver?

A.As I don't own a P8 Lite anymore and I can't test it, I can't respond to this question. But the public can!

2:

Q.Will this ROM get official updates?

A.In this moment, no. If OpenKirin or our team can fix some more bugs on the Oreo device tree, maybe I will.

3:

Q.How is battery life?

A.As I said, I don't own the device anymore, so public reviews will tell.

4:

Q.What is logcat?

A.It is a tool what reads the system while running and I can fix problems easier if I see exactly what causes the problem. You will need adb tools installed or linux or adb shell on windows and usb debugging enabled in Settings-Developer Options. If you cannot get a logcat, just tell me the problem. I'll still try to fix it.
[P8lite Android Development] GuestK00375:
Woah there you got footej working?
[P8lite Android Development] XTutorials:
Didn't footej work on RROS 6? I haven't tested the ROM so I don't know if it works or not.
[P8lite Android Development] GuestK00375:
Nope. It wasn't working in rr. In fact anything related to camera made apps bug really bad
[P8lite Android Development] XTutorials:
Well, let's hope it works here.
[P8lite Android Development] hassan001:
the rom doesn't boot up and i lost my good enough stock rom just to try this
[P8lite Android Development] XTutorials:
Really? Did tou follow the installation instrunctions? This is really important to me since I can't test the ROM.
[P8lite Android Development] hassan001:
the rom booted up but it shows only the starting huawei logo on the screen which is not going anyway
[P8lite Android Development] XTutorials:
What do you mean by:

booted

up but showing huawei logo? Please be more clear.
[P8lite Android Development] hassan001:
yes man i was already had a b896 installed , so i just went to the recovery and wipe cache,dalvik,system, Data and system and than this happen the huawei screen doesnt gone anywhere i can hear the notification sound but it doesnt show the actual rom
[P8lite Android Development] prakash09876:
Yes he is right while pressing volume button sound works and power button it lock the phone ,but it doesn't shows the launcher it only shows Huawei logo and stuck in it.Beside this sound also came when I plugged in charger and take it out.