FORUMS
Remove All Ads from XDA

Imrpoving sound quality of Erisin PX5 9.0 Android HU - USB DAC?

7 posts
Thanks Meter: 0
 
By mh5039, Junior Member on 14th November 2019, 11:55 AM
Post Reply Email Thread
I recently purchased an Erisin head unit and for the most part I'm really happy with it. It was plug and play with my BOSE system although I am a little worried I haven't attached the amp control cable (not sure where its supposed to attach) and it still works with my BOSE system despite it having separate amplifiers.

There is however a fair bit of static noise which appears to be alternator noise as there is no noise when the engine is off and increases with engine RPM. I've been told this is a grounding issue. When people say this are they referring to grounding within the amp or grounding within my car? Also would shielding the amplifier and cables help? Reducing cable length by cutting and soldering them? I believe ferrite beads can work with EMI, would they work?

The main reason for this post is to ask whether anyone has successfully used a USB DAC with a PX5 unit as I read a lot about it not working with these units. If this is possible how is this done? USB DAC going back into the RCA analogue inputs? How does the amp then know that its audio is re-routed back to itself?

Cheers,
Mike
15th November 2019, 03:35 AM |#2  
Senior Member
Flag North Pole
Thanks Meter: 25
 
More
Your grounds need to stay away from any audio signal wires and need to be as short as possible to avoid picking up noise from other wires in the car.
Also your signal wires need to be as short of a run and try to keep away from other power cords. If possible rca wires are the easiest way to reject noise but that's only if the amp will actually reject the noise that the rca pick up.
Sent from my Pixel 4 XL using Tapatalk
18th November 2019, 12:35 PM |#3  
OP Junior Member
Thanks Meter: 0
 
More
Quote:
Originally Posted by gjkrisa

Your grounds need to stay away from any audio signal wires and need to be as short as possible to avoid picking up noise from other wires in the car.
Also your signal wires need to be as short of a run and try to keep away from other power cords. If possible rca wires are the easiest way to reject noise but that's only if the amp will actually reject the noise that the rca pick up.
Sent from my Pixel 4 XL using Tapatalk

So should I cut the RCA outputs from the HU and solder them to the RCA inputs on the supplied harness as short as what is reasonable? Then as for grounds, I assume the ground is within the same harness as all the audio, I should find a new ground for it?

Cheers,
Mike
18th November 2019, 05:30 PM |#4  
Senior Member
Flag North Pole
Thanks Meter: 25
 
More
Do not cut the rcas there best left how they are but if you dac isn't Meant to run in a vehicle that may be your issue it's not been set up to reject noise from in a car specially if it was cheap.
if you get something like a Rockford Fosgate Punch PBR400X4D if size is an issue would be better as far as not needing to deal with so much trouble shooting to get ride of the noise.

Most car amifiers know how to reject the noise from the cables these days thru rca I'm not so sure about home audio dacs.


I'm sure it is possible to do what you want to do but your going to probably need every trick to stay away from putting noise into the lines.
Sent from my Pixel 4 XL using Tapatalk
18th November 2019, 06:33 PM |#5  
OP Junior Member
Thanks Meter: 0
 
More
Quote:
Originally Posted by gjkrisa

Do not cut the rcas there best left how they are but if you dac isn't Meant to run in a vehicle that may be your issue it's not been set up to reject noise from in a car specially if it was cheap.
if you get something like a Rockford Fosgate Punch PBR400X4D if size is an issue would be better as far as not needing to deal with so much trouble shooting to get ride of the noise.

Most car amifiers know how to reject the noise from the cables these days thru rca I'm not so sure about home audio dacs.


I'm sure it is possible to do what you want to do but your going to probably need every trick to stay away from putting noise into the lines.
Sent from my Pixel 4 XL using Tapatalk

Sorry I maybe wasn't all that clear. The USB dac question was separate. I'm getting alot of what I assume is alternator noise as it's only when the engine is on and increases with rpm. Interestingly it goes when the car is moving and there's no throttle. Not sure if alternators run if there's no fuel input or something.

As of yet I've determined it's a grounding issue. Does that mean grounding within the amp? The unit is an erisin unit and was supposed to be plug and play which for the most part it seems to be but I know the bose pin in the audi is to ground the HUs internal amplifier and I'm not sure it the android unit does that.

As of yet I've not tried anything so any suggestions are good.

Mike
18th November 2019, 10:10 PM |#6  
Senior Member
Flag North Pole
Thanks Meter: 25
 
More
Quote:
Originally Posted by mh5039

Sorry I maybe wasn't all that clear. The USB dac question was separate. I'm getting alot of what I assume is alternator noise as it's only when the engine is on and increases with rpm. Interestingly it goes when the car is moving and there's no throttle. Not sure if alternators run if there's no fuel input or something.



As of yet I've determined it's a grounding issue. Does that mean grounding within the amp? The unit is an erisin unit and was supposed to be plug and play which for the most part it seems to be but I know the bose pin in the audi is to ground the HUs internal amplifier and I'm not sure it the android unit does that.



As of yet I've not tried anything so any suggestions are good.



Mike

Yes the alternator will usually run all the time except in newer vehicles .
Ok that's good that you don't need to figure out if it's signal going to an external amp. Have you tried emailing the maker it shouldn't be an issue with ground inside the hu.
I'm surprised no one else is commenting on this but from this point I'd have to see pictures of what's going on and maybe a drawn out wire diagram.

Sent from my Pixel 4 XL using Tapatalk
21st November 2019, 11:36 PM |#7  
OP Junior Member
Thanks Meter: 0
 
More
Quote:
Originally Posted by gjkrisa

Yes the alternator will usually run all the time except in newer vehicles .
Ok that's good that you don't need to figure out if it's signal going to an external amp. Have you tried emailing the maker it shouldn't be an issue with ground inside the hu.
I'm surprised no one else is commenting on this but from this point I'd have to see pictures of what's going on and maybe a drawn out wire diagram.

Sent from my Pixel 4 XL using Tapatalk

Aye I'd assume they would but if I go down a hill and take my foot off the throttle, so the ecu would cut out the fuel supply, I'd assume the alternator would be generating a current as the engine is still moving but the noise stops.

Actually maybe I shouldn't sound so confident, my browsing of forums suggests it's a grounding issue but I actually have very little knowledge of electronics. All I know is that I've taken out an Audi Rns-e OEM head unit in a car with separate OEM installed amplifier as part of the bose sound system upgrade.

There's no noise when the engine is off, the noise starts when the engine is turned on and is effected when you turn screen brightness up, and when you touch the screen. It also increases with rpm. There is a range of low and high frequency noise.

The head unit bought:

https://rover.ebay.com/rover/0/0/0?m...2F383205297789

They have offered me a refund if I want it but I do actually like the unit, the sound quality isn't bad and the functionality is so good. So if it's something I can fix Id rather fix it. They've suggested using a high to low converter in what I think is using the amps amplifier and converting that input back down to use as the line input for mine but I see no point in having a good amp to do that. But I suppose that should give some insight into where the issue comes from.
Post Reply Subscribe to Thread

Guest Quick Reply (no urls or BBcode)
Message:
Previous Thread Next Thread
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes