Database Info

[HELP] headphones jack output burned out

While I was trying my car radio mods for a jack input, I probably make for error a short citcuit to some cable at 12v with my phone jack output
My phone crashed and restarted itself. All seems ok, but now when I try to use my jack output (for example with normal headphones) I have a lot of background noise, and when I try to turn up the volume above a certain treshold, I get a lot of distortion and the music is not "listenable" (simply horrible, only strange sounds distorted and so on..).
I have another photon Q (FAIL sim mod but working) and I was trying to see the resistence values from the jack output to the components near the output, but I can't se any differences with my headphone-broken-board.
The music works well if I use the internal speaker, the problem is only with headphone, jack output.
Someone can help me? Someone have the circuit of the board near the jack out to understand what I have burned out?
I hope so

Try replacing the jack from your other only held in with double sided tape
Sent from my XT897 using Tapatalk

You might want to use a bluetooth headset with a headphone jack in the future. Just to make sure that the actual expensive thing won't get hurt.
With such bluetooth headset you don't even need the jack at your Photon Q
I assume that some resistor or fuse has been blown up.
But I don't have experience in such things.

thanks for your replies!
bluetooth is good idea, I was considering also a microUSB to jack out, so I don't waste energy for bluetooth connection.. do you know if photon q can handle jack out from microUSB or microHDMI out?
I have replaced the back cover with the other one of the 'good working' phone, but the problem is here.. I think some resistors or capacitor is broken, it seems a filtering issue or a output impedance issue.
I could remove resistors from the other board and solder in my board, but I don't know what is broken and I don't know the circuit logic.
would love to repair circuit, otherwise I could solder a micro hdmi/usb to jack out in the phone to replace the standard jack out.. ahah! But is not so easy

Over microHDMI it can but only digital, not analog. Useless for a car radio.
Never tried over microUSB. But I think it's also digital.
The energy which is lost because of bluetooth is not really more than the analog sound over the headphone jack.
Listening music for about 6 hours (with sometimes texting/surfing for about 50 minutes) I get nearly 40% battery used.
Bluetooth is on, day and night. As long as it is not connected to anything, the energy usage is nearly zero.

Loader009 said:
Over microHDMI it can but only digital, not analog. Useless for a car radio.
Never tried over microUSB. But I think it's also digital.
The energy which is lost because of bluetooth is not really more than the analog sound over the headphone jack.
Listening music for about 6 hours (with sometimes texting/surfing for about 50 minutes) I get nearly 40% battery used.
Bluetooth is on, day and night. As long as it is not connected to anything, the energy usage is nearly zero.
Click to expand...
Click to collapse
thanks for your info. I have never used bluetooth so much
But what about similar cables: http://it.aliexpress.com/item/Micro...er-For-Nokia-E52-E72-N900-8600/547805050.html
Perhaps some phone can handle analog output from microusb?
If photon q is able to do this, and if in that cable is not present some type of circuit, i can solder the correct cables from microusb to standard jack out. I could lose mic input, but I don't use it..
I'll try to find similar cables in my zone for testing, before buy it
edit: this thread is great http://forum.xda-developers.com/showthread.php?t=1321491
i think that soldering similar things in my phone I could never use my usb port for data again
for now I'll buy similar cable. I hope to find a way to repair my board anyway

If you have a microUSB cable, you could theoretically cut it and try it out.
But you need to know the correct colorcode for this cable, maybe wikipedia is useful.
Still, I think the audio over microUSB is only for the docking station.
(Never tried that, pure theory.)

This cable should do what you need: http://www.amazon.com/Motorola-Audio-Power-SKN6394A-Bionic/dp/B00H8YATYI
It comes with the original Photon Q car dock and when it's connected, the phone switches to EMU audio output - analogue audio output on USB pins.
I've done the coding work so this cable is supported in CM 10.2/11 (changes to kernel, audio HAL and framework).
I haven't tried to figure out how it's actually wired and what resistor values are used between what pins so the connection of this cable is recognized by the phone as there was no need for me - the cable I have works just fine. I can try to measure it if you need it, but I unfortunately can't promise when I actually find the time for it - I would need to make some preparation with usb female connectors I don't have handy currently.
Your issue sounds like you've damaged some part of the headphone amplifier. I don't know the hardware details of how it's exactly wired in the case of Photon Q. I suppose it's using a separate Speaker amplifier TPA2015D1 (as used in Atrix HD), but the headphone output may be coming almost directly from the WCD9310 headphone output. Not sure.

kabaldan said:
This cable should do what you need: http://www.amazon.com/Motorola-Audio-Power-SKN6394A-Bionic/dp/B00H8YATYI
It comes with the original Photon Q car dock and when it's connected, the phone switches to EMU audio output - analogue audio output on USB pins.
I've done the coding work so this cable is supported in CM 10.2/11 (changes to kernel, audio HAL and framework).
I haven't tried to figure out how it's actually wired and what resistor values are used between what pins so the connection of this cable is recognized by the phone as there was no need for me - the cable I have works just fine. I can try to measure it if you need it, but I unfortunately can't promise when I actually find the time for it - I would need to make some preparation with usb female connectors I don't have handy currently.
Your issue sounds like you've damaged some part of the headphone amplifier. I don't know the hardware details of how it's exactly wired in the case of Photon Q. I suppose it's using a separate Speaker amplifier TPA2015D1 (as used in Atrix HD), but the headphone output may be coming almost directly from the WCD9310 headphone output. Not sure.
Click to expand...
Click to collapse
Thanks for your help.
I'll buy one of these cable for now, but I would like to repair anyway my photon Q headphone output.
I could find this WCD9310 in the board: I have a rework station so I could swap that chip from my other photon Q hoping to solve the issue..
But the output signal in headphones seems disturbed, usually I know that the digital electronics either works or it does not work .. it seems a problem of analog electronics, filtering or output impedance. I'm wrong? Or maybe within the WCD9310 there is some analog circuit?

nagash91 said:
Thanks for your help.
I'll buy one of these cable for now, but I would like to repair anyway my photon Q headphone output.
I could find this WCD9310 in the board: I have a rework station so I could swap that chip from my other photon Q hoping to solve the issue..
But the output signal in headphones seems disturbed, usually I know that the digital electronics either works or it does not work .. it seems a problem of analog electronics, filtering or output impedance. I'm wrong? Or maybe within the WCD9310 there is some analog circuit?
Click to expand...
Click to collapse
The Qualcomm proprietary audio hub WCD9310 contains also integrated headphone amplifier.
See the MSM8960/PM8921/WCD9310 reference design schematics:
http://d-h.st/xJ9
Sheets 28 and 29.
You can see that there are only resistors and transient voltage suppressors between the headphone jack and WCD9310 HPH outputs.

kabaldan said:
The Qualcomm proprietary audio hub WCD9310 contains also integrated headphone amplifier.
See the MSM8960/PM8921/WCD9310 reference design schematics:
http://d-h.st/xJ9
Sheets 28 and 29.
You can see that there are only resistors and transient voltage suppressors between the headphone jack and WCD9310 HPH outputs.
Click to expand...
Click to collapse
You're giving me a great help, thank you.
Unfortunately I'm not so good with integrated circuit or similar.
What I can understand from the sheets:
- J6 JA13331-SW38-4F at top-right of sheet 29 is the jack output socket.
- Pin 1 and 4 are right and left headphone signals.
- As you said, the pin 1 and 4 goes to the WCD9310: HPH_LP pin 12, HPH_RM pin 17, and HPH_REF pin 18 (i think is the headset "gnd")
- As you said, between pin 1 and pin 4 of jack input and the WCD9310, there are only resistors, capacitors, and voltage suppressors.
So I understand: the problem are these voltage suppressors or capacitors or resistors or WCD9310 ! :laugh:
You said that probably is WCD9310.. you are more expert than me of coures, and I hope the only problem is the WCD9310 because is the easier component to locate and replace!
I could try to swap the WCD9310, but I don't know where is locate in photon Q, and all IC in the board are covered from metal cases.
I can remove all the metal covers from my 2nd photon Q until I find WCD9310.. but I'll destroy that board definitively.
It is possible that there is so little information on the photon q on the internet? I would like to find a circuit schematics, or at least an info about how the IC are placed in the board.

Good news!!!!!!
I have found WCD9310 in my broken board!!
I'll remove also the other two "capsule" and I'll make a detailed photo, it could be usefull for other problems :laugh:
back with SanDisk 8gb "ssd":

[Solved] How to pass audio to premium (Bose) amp from PX5 MTCD HU (2013 Mazda CX-7/9)

Hello,
I am having trouble passing meaningful audio to a Bose factory amp from my PX5 MTCD (said amp comes with my 2013 Mazda CX-9 but I believe that the same hardware can be found in other contemporary Mazda vehicles). Instead of audio I only get a 2Hz very loud beep. The best guess (by me and the PAC guys) as to what happens is that the signal level is too high for the Bose preamp (which is known to have a low impedance) so that the amp is overloaded. I am feeding said amp directly from the preamp outputs of the unit. I believe (but I am not sure) that the way the unit is interfaced with the CAN bus is immaterial to the issue. Indeed, I connected the unit using the included CAN bus adapter as well as a PAC RP4-MZ11 adapter with the same result.
So my question is, is there a way to control the gain of the preamp outputs of such a unit? Do you guys have any other advice on what to try to fix this issue? Wild guesses are welcome (I am willing to experiment).
Thoughts are much appreciated. Many thanks!

In my Audi B7, which also uses a Bose amp like this, I used 2:1 step-down audio transformers along with a resistor divider network on the SPK out from the android headunit. I found the line out level to be too low to drive the transformers, and couldn't connect line out directly to amp due to non-isolated ground.

JAmBer99 said:
In my Audi B7, which also uses a Bose amp like this, I used 2:1 step-down audio transformers along with a resistor divider network on the SPK out from the android headunit.
Click to expand...
Click to collapse
Great tip, thank you very much. I will try it as soon as I can. Do you happen to remember the overall resistance and the ratio for the divider?
JAmBer99 said:
couldn't connect line out directly to amp due to non-isolated ground.
Click to expand...
Click to collapse
So that's what causes the trouble. Good to know, thank you again. Much appreciated.

For the record, it turned out that my issue was caused by the CAN bus adapter rather than audio source. Strangely enough, the adapter requires that the car be turned on (and that's a full on, not just ACC) for the first time. If this is not the case then max volume beeps are all the sound that is produced by the amp. As soon as the car is turned on once the amp/head unit combination will work thereafter on ACC as well as on ON.
This appears to be a "feature" of the vehicle rather than the adapter, as the same problem manifested itself with two totally different adapters (PAC RP4-MZ11 as well as the adapter that came with the head unit).
With this proviso the preamp outputs of the head unit drive the amp well, so that there was no need for a line converter in my installation. The preamp level is pretty high (so volume beyond 25% or so is unusable) but this can easily be fixed by playing with the gain on the head unit.

[PX6] Subwoofer Volume very low

I have a Dasaita PX6 4gb/64gb with DSP running android 9.
It seems like the subwoofer output is very low, I performed a standard subwoofer amplifier RMS tuning,
Disconnected Subwoofer from NVX Amp, Played a 50hz test tone, and turned up the volume to the maximum on the Head Unit. Then measured the speaker output of the amp with a multimeter. Even with the Level turned up to maximum, I only got about 9 Volts. I'm expecting an RMS level of around 34 volts (sqrt (2ohm * 600RMS))
I checked the settings in the "Amplifier" app and the subwoofer gain was turned up all the way.
With the volume on the stereo at a reasonable level, I was only getting 1-2 volts output of the amplifier.
Anyone have any ideas? is this a DSP/software problem Dasaita needs to fix?

Ive got similiar problem. Any advice how to get biggher preamp for the RCA connections?

I ended up buying an RCA line input booster, like this one
https://www.amazon.com/dp/B003LWV77Y/ref=cm_sw_r_other_apa_i_ARwjDb2NE3SJX
and that solved my problem. I think the voltage that the DSP is putting out is just way too low for most amplifiers to detect and isn't getting past the amp input gate.
I think this is a software fix Dasaita needs to make if their hardware can handle it.

I just installed my head unit and now my factory alpine subwoofer in my wrangler does not work... any ideas?

@hotaudio we have at least 3 people here that are having subwoofer output level problems, can you comment?

Has this gotten fixed? I am looking at buying a PX6 4gb/64gb desaita for outlander Phev 2014.
Sent from my Pixel 3 XL using Tapatalk

No updates that I am aware of. Again I was able to work around it by buying a line level booster.

evilflame2 said:
@hotaudio we have at least 3 people here that are having subwoofer output level problems, can you comment?
Click to expand...
Click to collapse
What have you measured the line output to be at 0db to ascertain 'problem'?

marchnz said:
What have you measured the line output to be at 0db to ascertain 'problem'?
Click to expand...
Click to collapse
I thought I performed this test with a 0db 50hz test tone, I measured 9volts on my amp speaker terminals, with every volume turned up to maximum (amp, head unit, bass boost etc...)
I expected to be tuning my amp to around 34 volts. After buying the line output amplifier, I was able to accomplish a standard amplifier tuning procedure.
If there is another test I should be performing let me know how to do it. Thanks.

You really need an external aftermarket amp if your expectation is having base. These units dont have a strong amp despite there being a sub out. I have an xtrons. Basic sound was ok, with a jbl amp behind it its mental. Even on the stock speakers. There is no head unit i know of that has good base(sub) out without an external amp.

ghost010 said:
You really need an external aftermarket amp if your expectation is having base. These units dont have a strong amp despite there being a sub out. I have an xtrons. Basic sound was ok, with a jbl amp behind it its mental. Even on the stock speakers. There is no head unit i know of that has good base(sub) out without an external amp.
Click to expand...
Click to collapse
That's interesting! I have zero experience with car audio, but love good sound...what amp are you talking about specifically?
Sent from my Pixel 3 XL using Tapatalk

ghost010 said:
You really need an external aftermarket amp if your expectation is having base. These units dont have a strong amp despite there being a sub out. I have an xtrons. Basic sound was ok, with a jbl amp behind it its mental. Even on the stock speakers. There is no head unit i know of that has good base(sub) out without an external amp.
Click to expand...
Click to collapse
Sorry if I was not clear, I do have an external amp 750w NVX.
Just to get the sub signal to pass the noise gate so the amp functions, I need the line signal booster on the sub output. That is unacceptable for the price we are paying for a product like this.

evilflame2 said:
Sorry if I was not clear, I do have an external amp 750w NVX.
Just to get the sub signal passed the noise gate so the amp functions, I need the line signal booster on the sub output. That is unacceptable for the price we are paying for a product like this.
Click to expand...
Click to collapse
My unit dasaita max6 that I have ordered but not received yet is supposed work with the cars Rockford fosgate system so I imagine it will feed the amp since the RF-amp is a separate unit from the original head unit. So hopefully that won't be an issue... Anyone else with this setup that can confirm/not confirm this working properly?
Sent from my Pixel 3 XL using Tapatalk

Rawb1 said:
My unit dasaita max6 that I have ordered but not received yet is supposed work with the cars Rockford fosgate system so I imagine it will feed the amp since the RF-amp is a separate unit from the original head unit. So hopefully that won't be an issue... Anyone else with this setup that can confirm/not confirm this working properly?
Click to expand...
Click to collapse
Most amplifiers have what is called a noise gate, which basically doesn't let the sound through until it reaches a certain threshold (voltage). I guess it would depend on how your car sends the subwoofer signal from the px6 to your amp. If it uses the sub rca jack then you may run into the same issue.

evilflame2 said:
I have a Dasaita PX6 4gb/64gb with DSP running android 9.
It seems like the subwoofer output is very low, I performed a standard subwoofer amplifier RMS tuning,
Disconnected Subwoofer from NVX Amp, Played a 50hz test tone, and turned up the volume to the maximum on the Head Unit. Then measured the speaker output of the amp with a multimeter. Even with the Level turned up to maximum, I only got about 9 Volts. I'm expecting an RMS level of around 34 volts (sqrt (2ohm * 600RMS))
I checked the settings in the "Amplifier" app and the subwoofer gain was turned up all the way.
With the volume on the stereo at a reasonable level, I was only getting 1-2 volts output of the amplifier.
Anyone have any ideas? is this a DSP/software problem Dasaita needs to fix?
Click to expand...
Click to collapse
Hi
Do you know the type of the DSP chip?
I have similar problem with isudar h53 unit. The subwoofer voltage lover than the 4 cahannel voltage.
The filter can be adjusted but the gain not works on sub channel.
DSP chip BU32107EFV

vegfokic said:
Hi
Do you know the type of the DSP chip?
I have similar problem with isudar h53 unit. The subwoofer voltage lover than the 4 cahannel voltage.
The filter can be adjusted but the gain not works on sub channel.
DSP chip BU32107EFV
Click to expand...
Click to collapse
How do I determine my type of DSP chip? thanks

evilflame2 said:
How do I determine my type of DSP chip? thanks
Click to expand...
Click to collapse
I opend the head unit and checked the chips. In my case the dsp chip was on the back side of main board.
Yesterday I added a signal amplifier for two front ch and the sub ch. Now I can got 3,6V without distorsion of the two front ch but the sub ch at same volume ~2,1V. Checked 50Hz test signal. At the moment Im waiting for the seller response, what about the loudness control and sub gain control why they not work.

Did you get an answer from dasaita about this?

vegfokic said:
I opend the head unit and checked the chips. In my case the dsp chip was on the back side of main board.
Yesterday I added a signal amplifier for two front ch and the sub ch. Now I can got 3,6V without distorsion of the two front ch but the sub ch at same volume ~2,1V. Checked 50Hz test signal. At the moment Im waiting for the seller response, what about the loudness control and sub gain control why they not work.
Click to expand...
Click to collapse
I have the same problem with my sub out channel on my PX6. I upped the gain on my amp to compensate. I have a audio control amp with distortion indicator and cranked it up to about 80% gain without distortion to get good sound out of my subwoofer.
---------- Post added at 06:25 PM ---------- Previous post was at 06:22 PM ----------
evilflame2 said:
Sorry if I was not clear, I do have an external amp 750w NVX.
Just to get the sub signal to pass the noise gate so the amp functions, I need the line signal booster on the sub output. That is unacceptable for the price we are paying for a product like this.
Click to expand...
Click to collapse
Yeah the RCA sub output didnt have enough to turn on my AudioControl amp either. I ended up running the remote turn on wire to the fuse box an tapped there for switched power.

I know this issue too.
Is this caused by the hardware in the radio or is this maybe some software issue? Firmware or MCU maybe?

Enabling RCA Audio outputs?

Hello everyone
I tried to use the RCA Line-Level audio outputs of my Dasaita MTCD-PX5 unit to connect an external amplifier, but discovered that there's no signal coming out of them.
Do I need to enable them somewhere on the SW?
Thanks in advance
Max

Hi Max,
I am having the same issue, with Seicane PX30. I have temporarily spliced into the speaker wires since my amp can take high voltage input, however I have static/ clipping noise with high volume.
Please let me know if you figure this out!

SoakedCardinal said:
Hi Max,
I am having the same issue, with Seicane PX30. I have temporarily spliced into the speaker wires since my amp can take high voltage input, however I have static/ clipping noise with high volume.
Please let me know if you figure this out!
Click to expand...
Click to collapse
What did the reseller suggest.

currently in communication with support, sent them this:
I have purchased 2014 2015 2016 Subaru WRX Forester 9 inch Android 10.0 Head Unit.
There is no signal coming from the following RCA jacks:
• SUBWOOFER
• FL OUT
• FR OUT
• RL OUT
• RR OUT
They all register 0 volts using 40hz 0db test tone ¾ volume from bluetooth or auxiliary input.
Connecting AUX IN L/R to FL/FR OUT makes the cars 3.5mm aux jack work but there is still no output from the RCA jacks.
My unit has the DSP Sound System. I have seated the connector properly. All other functions are working normally.
How can I make it work?
Click to expand...
Click to collapse
they completely misunderstood my issue first go round . . will report back

SoakedCardinal said:
currently in communication with support, sent them this:
they completely misunderstood my issue first go round . . will report back
Click to expand...
Click to collapse
On my side, I never found a solution. Played around with several settings, but nothing...
Could this be a ROM issue?
Let me know if they ever reply back

marchnz said:
What did the reseller suggest.
Click to expand...
Click to collapse
maxiauer said:
On my side, I never found a solution. Played around with several settings, but nothing...
Could this be a ROM issue?
Let me know if they ever reply back
Click to expand...
Click to collapse
so . . they basically tried to bribe me $50 to stop bothering them.
I think I might be able to fix the crackliing by using my amp to sum the L + R speaker outputs instead of my homade y splitter from the stock speaker cables at the headunit . .

Sorry for the resurrection, but I just fixed this issue on my PX5 for anyone else running into this problem. TL;DR is that the harness does not have the RCA for Rear speaker outputs wired in but the PX5 DOES have the pins for it. The solution is to wire them into the harness.
SOLVED: Rear RCA Outputs for MTCE PX5
Edit: TL;DR The wiring harness does not have Rear RCA outputs (only front and subwoofer). I had to splice in the RCA for the rear because there are pins outputting signal. (See solution below for details) I'm running Hal9K Mod with Android 10...
forum.xda-developers.com

Hey guys!
I've just bought a PX5 Android head unit to Skoda Octavia 3, instead of MIB1 Bolero. Everything works fine, it's fast, but I have 2x2ch amps in car.
RCAs don't give any signal at all..... Nor rear or front, neither sub RCA-s. Wiring is perfect.
In Factory menu i could find a Power Amplifier Settings menu, but it's gray, can't be opened.
In the scroll down menu, no possibility to activate AMP.
Remote switches both amps, connecting a phone via 3,5mm jack to amplifiers, it works fine. When I connect back to the head unit, it stops working. I can only hear it working like 5% of the sound it should...
We measured if there is rupture with multimeter, we measured 0... no beep. Moreover we tried to measure the outcoming signal, but nothing. it's 0,00. On every RCA. Anyone any tips?

kukoladam said:
Hey guys!
I've just bought a PX5 Android head unit to Skoda Octavia 3, instead of MIB1 Bolero. Everything works fine, it's fast, but I have 2x2ch amps in car.
RCAs don't give any signal at all..... Nor rear or front, neither sub RCA-s. Wiring is perfect.
In Factory menu i could find a Power Amplifier Settings menu, but it's gray, can't be opened.
In the scroll down menu, no possibility to activate AMP.
Remote switches both amps, connecting a phone via 3,5mm jack to amplifiers, it works fine. When I connect back to the head unit, it stops working. I can only hear it working like 5% of the sound it should...
We measured if there is rupture with multimeter, we measured 0... no beep. Moreover we tried to measure the outcoming signal, but nothing. it's 0,00. On every RCA. Anyone any tips?
Click to expand...
Click to collapse
Send it back under warranty.

marchnz said:
Send it back under warranty.
Click to expand...
Click to collapse
The problem is, that is another week of waiting. I am in connection with the supplier, he asks the manufacturer about the problem. The way is good, since when I plug Front left to the Front left of the amplifier, I head very very weak sound from the front left speakers. But the outcoming signal is unmeasurable. In addition, in the Factory menu there is an option "Power Amplifier Settings", which is gray. Can't be reached..
Maybe somehow it is disabled in the menu, but I could not find in 3 hrs where.

kukoladam said:
Hey guys!
I've just bought a PX5 Android head unit to Skoda Octavia 3, instead of MIB1 Bolero. Everything works fine, it's fast, but I have 2x2ch amps in car.
RCAs don't give any signal at all..... Nor rear or front, neither sub RCA-s. Wiring is perfect.
In Factory menu i could find a Power Amplifier Settings menu, but it's gray, can't be opened.
In the scroll down menu, no possibility to activate AMP.
Remote switches both amps, connecting a phone via 3,5mm jack to amplifiers, it works fine. When I connect back to the head unit, it stops working. I can only hear it working like 5% of the sound it should...
We measured if there is rupture with multimeter, we measured 0... no beep. Moreover we tried to measure the outcoming signal, but nothing. it's 0,00. On every RCA. Anyone any tips?
Click to expand...
Click to collapse
As @marchnz .... send it back under warranty.
Every head unit I have ever had, there is no turn-on for the RCA's because they are already on. That includes my old px5 and new px6.... and I have been using RCA outs only for probably the last 40 years
What you could do is check the pins directly on the head unit plug to see if there is anything there. When you probe it with the multimeter try using a ground inside the machine instead of the ground on the plug.

Bob_Sanders said:
As @marchnz .... send it back under warranty.
Every head unit I have ever had, there is no turn-on for the RCA's because they are already on. That includes my old px5 and new px6.... and I have been using RCA outs only for probably the last 40 years
What you could do is check the pins directly on the head unit plug to see if there is anything there. When you probe it with the multimeter try using a ground inside the machine instead of the ground on the plug.
Click to expand...
Click to collapse
Optical toslink between audio equipment is highly preferred.
Even with a common grounding point for -all- connected equipment the chance of an unsnubbed high frequency feedback loop is real.
If so it will likely blow all your twitters and possibly the power amp in seconds*.
If the amp's big enough you'll see smoke and fire
At the very least use a common grounding point for all pieces of equipment. Use heavy gauge wire and keep the wire length as short as possible.
*A high frequency typically 40hz or higher feedback loop when fed into and/or through a power amp will result in a huge wattage output at that frequency. It will cause the speaker bypass to shunt all of it through your tweeters and effectively short out the power amp

You probably know much more about this than I do, but a few things don't make sense to me. You said high frequency feedback loop, but then referenced 40hz. Did you mean 40khz? 40hz is a pretty low frequency and I would think would be cut out by both integrated HPFs and amp level HPFs. I am very familiar with toslink as I use them between my PC and home audio amplifier, but I've never heard of them used between a head unit and amp. Every head unit and amp I've ever owned have used RCA outputs. I'm not saying the risk isn't there but why would both head unit and amp manufacturers not use them if RCA is so dangerous? It really is an honest question, so please don't take offense.

blackhawk said:
Optical toslink between audio equipment is highly preferred.
Click to expand...
Click to collapse
Well... toslink is preferred in high end equipment (bandwidth suffers in the cheap stuff).... and I would not describe these head units as "high end"
blackhawk said:
Even with a common grounding point for -all- connected equipment the chance of an unsnubbed high frequency feedback loop is real.
If so it will likely blow all your twitters and possibly the power amp in seconds*.
Click to expand...
Click to collapse
I think you misunderstand. I'm asking OP to look for a common ground FOR TESTING with his multimeter. If all the rca's are not working then there is a chance that something common (like the ground on the rca jacks) is broken.

objecttothis said:
You probably know much more about this than I do, but a few things don't make sense to me. You said high frequency feedback loop, but then referenced 40hz. Did you mean 40khz? 40hz is a pretty low frequency and I would think would be cut out by both integrated HPFs and amp level HPFs. I am very familiar with toslink as I use them between my PC and home audio amplifier, but I've never heard of them used between a head unit and amp. Every head unit and amp I've ever owned have used RCA outputs. I'm not saying the risk isn't there but why would both head unit and amp manufacturers not use them if RCA is so dangerous? It really is an honest question, so please don't take offense.
Click to expand...
Click to collapse
RCA's are mostly used on automotive head units. They have been around for decades. toslink is the new kid on the block and there are a lot of problems with it... frequency issues, sample matching issues, select few apps to use toslink with... yadda yadda. Personally speaking, I wouldn't use toslink instead of rca in a million years. Now it does have the advantage of less noise pickup on long runs of cable, but manucacturers like pioneer, alpine, kenwood... etc have combatted the noise issues with high voltage output from the rca's (pioneers are now 4 volts peak to peak on the rca's while android is still something like 1.4 volt PtoP). Then on the other hand with toslink you need HIGH QUALITY dac's to avoid sample and frequncy issues... and these android head units are NOT what I would describe as anywhere NEAR "high end"+
toslink.... not me thank you... not at this low price level anyway.
As for blowing tweets with stray "40hz" signals.... hasn't happened to me in 40 years of using rca's

Bob_Sanders said:
Well... toslink is preferred in high end equipment (bandwidth suffers in the cheap stuff).... and I would not describe these head units as "high end"
Click to expand...
Click to collapse
Just a friendly old school warning so peeps never learn what driver coils smell like...
Cheap stuff will likely have less design fedback safeguards than high end equipment.
Regardless of the amp's frequency response the fed back will be on the high end. 10khz would still behave like 60khz as far as the crossover is concerned.
Regardless its best to wire/ground it proper for best performance and minimal voltage drops... wire is cheap.
I have a friend that saw this happen on a high end system. All they heard was a static like noise and in less than a second the tweeters were smoking. A couple hundred down the drain. It can get real expensive fast and by the time you realize it's happening, it's already done.

Yeah, I don't think anyone sees these as high end in the audio production department. I think they have become somewhat popular because a lot of the main players in audio head units have been a little slow in the freedoms that Android provides in terms of apps, navigation, etc. They are too busy pushing their proprietary interface crap.

blackhawk said:
Just a friendly old school warning so peeps never learn what driver coils smell like...
Cheap stuff will likely have less design fedback safeguards than high end equipment.
Regardless of the amp's frequency response the fed back will be on the high end. 10khz would still behave like 60khz as far as the crossover is concerned.
Regardless its best to wire/ground it proper for best performance and minimal voltage drops... wire is cheap.
I have a friend that saw this happen on a high end system. All they heard was a static like noise and in less than a second the tweeters were smoking. A couple hundred down the drain. It can get real expensive fast and by the time you realize it's happening, it's already done.
Click to expand...
Click to collapse
You can blow a simple ic chip with static so we shouldn't use them? Freak things happen. That's life.

Bob_Sanders said:
You can blow a simple ic chip with static so we shouldn't use them? Freak things happen. That's life.
Click to expand...
Click to collapse
No that's ignorance and ineptitude.
I handled thousands of IC's and flat packs without damaging them by heat or ESD.
On a high end system with 7 mains blowing them out alone would be over $2G in replacement parts.
Anything worth doing is worth doing right.

objecttothis said:
Yeah, I don't think anyone sees these as high end in the audio production department. I think they have become somewhat popular because a lot of the main players in audio head units have been a little slow in the freedoms that Android provides in terms of apps, navigation, etc. They are too busy pushing their proprietary interface crap.
Click to expand...
Click to collapse
Well... as far as I know the higher end units are still going RCA..... and if there is ever a change I suspect toslink will be passed over in favor of the MUCH BETTER hdmi standard anyway.

Px6 Dasaita rca level outputs not working

After a few months of running a stock stereo system, I decided to spend 3.5k on a sound system and can not get any signal to come out of the rca outputs to the amp. Ive been scouring the net all week and all ive found is solutions to noise. I get 0 output from my rca's. Neither "Sub1 or Sub2" outputs work, and win i try and hook subwoofer up thru rear rca's, they dont work either. Anyone know the solution?

Redbeard1980 said:
After a few months of running a stock stereo system, I decided to spend 3.5k on a sound system and can not get any signal to come out of the rca outputs to the amp. Ive been scouring the net all week and all ive found is solutions to noise. I get 0 output from my rca's. Neither "Sub1 or Sub2" outputs work, and win i try and hook subwoofer up thru rear rca's, they dont work either. Anyone know the solution?
Click to expand...
Click to collapse
Is the unit an mtcd type

marchnz said:
Is the unit an mtcd type
Click to expand...
Click to collapse
Mtce I believe

The RCA's just work. There should be no adjustment needed to make them work. Are you SURE there is no sound coming from the rca's? Maybe you just don't have the amp turn-on wire connected (blue wire). It's a pretty common mistake.
If you are SURE there is no rca audio then the unit is defective.

There isn´t any configuration about RCA on the unit. I have the same one. Only you have the option to turn on or off the amp remote cable. But just that.

In the Amplifier app where you can sett your EQ etc you also have a tab where you can change levels for loudness etc. In there you also have the opportunity to turn the sub ON/OFF and set the gain level of the sub.