USB audio out and charging at once, possible? - Galaxy S III Accessories

I need to use my phone as a car dock and pull digital audio out to a e.g. FiiO E7 DAC, also I need to charge my phone at the same time, is this possible? I know that the FiiO works with the S3, but not sure if simultaneous charging is possible.

grkn said:
I need to use my phone as a car dock and pull digital audio out to a e.g. FiiO E7 DAC, also I need to charge my phone at the same time, is this possible? I know that the FiiO works with the S3, but not sure if simultaneous charging is possible.
Click to expand...
Click to collapse
I would assume 2 cables would be needed. My Galaxy S 1 could output sound over USB, but I needed 2 cables. A cable for charging and the cable for sound.
Seeing as how power and data are on different pins I don't see why it's not possible.

grkn said:
I need to use my phone as a car dock and pull digital audio out to a e.g. FiiO E7 DAC, also I need to charge my phone at the same time, is this possible? I know that the FiiO works with the S3, but not sure if simultaneous charging is possible.
Click to expand...
Click to collapse
Having never actually used a fiio e7, but thinking I understand your post…
If the FIIO does not draw power from the phone (looking at pics on Amazon, it uses its own power source), and you saying it does not already provide power to the phone, I am going to say it is time for some surgery!
This is the wires inside a USB cord:
Pin Name Cable color Description
1 VCC Red +5 VDC
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground
So you need to splice a second USB cable in, that uses the 1 and the 4 ( red and black) to provide power from a car charger.
You will then have a cable that does this:
End one:
Pin Name Cable color Description
1 VCC Red +5 VDC
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground
End 2a (goes to FIIO)
Pin Name Cable color Description
1 VCC Red dead
2 D- White Data -
3 D+ Green Data +
4 GND Black dead
End 2b (goes to car charger)
Pin Name Cable color Description
1 VCC Red +5 VDC
2 D- White dead
3 D+ Green dead
4 GND Black Ground
Once I hit 10 posts, I can make a picture of it if you need.

It's my understanding that the GSIII does have the capability for USB audio out, but there's not a whole lot of hardware out yet to support it. One JB really starts rolling, there should be a bunch of new products hitting the shelves, but for now you may have to go with the splice idea above, or go with the 2 cable approach like the Inspire dock uses.

How about a USB y splitter http://www.amazon.com/StarTech-com-...F8&qid=1342471372&sr=8-3&keywords=usb+y+cable and the adapters to make it micro on the phone end etc. From the car 12V you'd only need the +,- and gnd?
scarrmrcc said:
Having never actually used a fiio e7, but thinking I understand your post…
If the FIIO does not draw power from the phone (looking at pics on Amazon, it uses its own power source), and you saying it does not already provide power to the phone, I am going to say it is time for some surgery!
This is the wires inside a USB cord:
Pin Name Cable color Description
1 VCC Red +5 VDC
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground
So you need to splice a second USB cable in, that uses the 1 and the 4 ( red and black) to provide power from a car charger.
You will then have a cable that does this:
End one:
Pin Name Cable color Description
1 VCC Red +5 VDC
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground
End 2a (goes to FIIO)
Pin Name Cable color Description
1 VCC Red dead
2 D- White Data -
3 D+ Green Data +
4 GND Black dead
End 2b (goes to car charger)
Pin Name Cable color Description
1 VCC Red +5 VDC
2 D- White dead
3 D+ Green dead
4 GND Black Ground
Once I hit 10 posts, I can make a picture of it if you need.
Click to expand...
Click to collapse

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Blue Angel - simple hardware detect for full battery?

Hi all! I'm going to try to come at the usb sync / charge cable not charging problem from a different angle - how could/should you be able to tell if the battery is fully charged and does this have any implications for cable construction?
My much abused cable has, as far as I can tell, all the right connections but after I get the green 100% charged indicator for a couple of minutes, it discharges and I am trying to figure out why, thinking about hardware first.
The cable I'm using is [2,5,16,17,18 - GND], [13,20,21,22 - VCC], [14 - USB_D+], [15 - USB_D-].
Can anyone help? Suggestions would be welcome! ta...
The answer seems to be yes in that there is a simple hardware fix to allow the phone to manage its own charging.
For a usb sync / charge cable, USB_data+ and USB_Data- go to pins [14] and [15], GND goes to GND pins [16,17,18]and VCC goes to USB_VDD pin [13] and then the detection is enabled by connecting [13] to pins[20,21,22] through a 0.15 Ohm resistor. This enables the phone to measure and manage current flow.
This cable works with the usb port on my notebook as well as through a usb cigarette lighter adapter and a usb wall charger adapter. With the ciggie adapter at 12v, it takes between 0.17/0.19 amps with occasional peaks at 0.27 amps, mostly hovering <0.2 amps. I was going to use a ps2 - usb mouse convertor to power the phone at 5v (easy to bodge wires into the holes in a female ps2 connector!) to check the 'normal' current level on a usb port, but life is too short!
Running the cable through the lighter dapter with a gps mouse attached, the current goes to 0.3/0.35 amps with occasional peaks at 0.39/0.4 amps.
Hope that this helps someone in the future!

Serial COM port in HTC proprietary USB

I found special solutions - possibility to use COM ports on most of HTC devices
You have to use spcial Nokia's cabel DCU-5 and 11pin miniUSB HTC plug .
After cutting it close to Nokias plug you can find four wire.
Please chceck voltage on connected to PC USB .
White ( earth)
Red 0,15V
Blue 2,34V
Green 0,49 V
If you have the same voltage it's mean
Blue is TX
Green is RX
So you can find in HTC miniUSB possiblity to finnd Tx and RX as on drawing .
To connect with PC you need to use Nokia's driver for virtual port .
Maybe better solution will be use of max3232 circut .
Very good!
do you know the corresponding colours in htc's extusb headset cable? i mean what to connect the dku-5 wires to in the extusb cable, because i don't have breakout board.
According to drawing http://www.tracyandmatt.co.uk/blogs/media/EMU_pin_config.png
I founnd colours only for audio pins in ExtUSB :
Data pins has to be standard colour code , I think .
So please chceck
A = GND colour Black
B = NC
C = +DATA colour White
D = -DATA colour Green
E = +5v Colour Red
Audio pins
1 = +Mic colour White
2 = +Right colour Red
3 = Switch colour Blue
4 = Gnd Colour Red-Yellow
5 = Mic Gnd/Antenna Colour Yellow
6 = +Left Colour Green
What about charging?
Hm, so this means that if we use this scheme to connect a serialport to the miniUSB-connector we cannot charge the PDA at the same time unless we put separate charging-wires on the +5V and GND...
I have been in contact with HTC about this because we are desperately looking for a solution for a problem we have. We use HTC Advantage 7500/7510 who have a USB-host built-in and using the VGA-out-multi-cable that comes with the 7510 we can get a serialport using a usb-to-serial-connector, but the one that HTC makes is a bit too big and we want to build the connector in to the vehicle cradle.
Your solution might actually work, we need to test this. Huge thanks for the info!!!
Couple of notes...
Instead of hunting for voltages on the various wires which may or may not be color coded the same way, it might be easier to look at the following page:
http://jethomson.files.wordpress.com/2010/02/ca-42_dku-5_pinout.jpg
And then (if you've got a continuity mode on your meter), just strip the end of the garbage half (dku-5 connector) of the cable you just cut and tone out the pins to figure out which color means what. It certainly made it tons easier for me. In my case the RS232 RX, TX, and GND were White, Green, and Red respectively.
Also, the drivers listed above may or may not work for you, depending on who made the cable you bought. I purchased mine on eBay for $4 US. The following table shows a list of various DKU-5 cables and their related linux driver (which may help you discern the manufacturer):
http://wiki.gnokii.org/index.php/Cables#DKU-5_and_CA-42
I attached my cable to a linux computer and ran "lsusb" from a terminal. This told me that my particular device was an ArkMicro Technologies 3116... Once I found drivers for that device for Windows XP, I was fine. I'm not sure how you'll figure out the device manufacturer from Windows, but someone here will figure it out
So if i modify the Nokia Cable, i can use it as serial wire to debrick the HTC G1/G2 ?

split micro usb socket in 2

Hi,
I have just bought the galaxy nexus and am wondering if any of you bright bods could think of a way to do this. I have a Fiat bravo with blue and me so use the usb port for media playback, however this does not supply enough power to keep the phone charging if using navigation too. I also have a 750mA 12 volt charger. Is there a cable that would allow me to have both the media player cable connected and the cigarette lighter cable connected at the same time, preferably with d- d+ shorted so that high speed charging would be available as the effective power available should be 1.2A if my thinking is correct

OTG cable + power

Do i need a custom Kernel to get that capability?? I have a OTG cable that works for connecting a mouse, keyboard, thumbdrive etc and it has a port for power but the tablet does not recharge.
So i'm wondering if i need a custom Kernel or maybe the cable is defective or something.
If you know of one of those cables that work, please let me know.
Thanks in advance.
I have this cable out of China:
treetop777 said:
Do i need a custom Kernel to get that capability?? I have a OTG cable that works for connecting a mouse, keyboard, thumbdrive etc and it has a port for power but the tablet does not recharge.
So i'm wondering if i need a custom Kernel or maybe the cable is defective or something.
If you know of one of those cables that work, please let me know.
Thanks in advance.
I have this cable out of China:
Click to expand...
Click to collapse
I use a Otg Cable with an Usb Stick and a Usb Mouse,works fine with 4.4.2 and 4.2.2 with Stock Kernel
letschky said:
I use a Otg Cable with an Usb Stick and a Usb Mouse,works fine with 4.4.2 and 4.2.2 with Stock Kernel
Click to expand...
Click to collapse
And also charges simultaneously? That's what the OP is asking for.
Slimport adapter outputs HDMI signal and lets you charge the tablet simultaneously, but besides that... nothing else on stock ROM I imagine.
Iknownot said:
And also charges simultaneously? That's what the OP is asking for.
Slimport adapter outputs HDMI signal and lets you charge the tablet simultaneously, but besides that... nothing else on stock ROM I imagine.
Click to expand...
Click to collapse
Bummer! That's what i was afraid off.
Hello I have the same problem! : (
I installed the tablet in my car but you can not use the charger + OTG simultaneously.
You have to wait for someone to change the KERNEL as they did for the Nexus 7.
mannyy said:
Hello I have the same problem! : (
I installed the tablet in my car but you can not use the charger + OTG simultaneously.
You have to wait for someone to change the KERNEL as they did for the Nexus 7.
Click to expand...
Click to collapse
Nice setup! :good: That's exactly what i want to do. I can connect a mouse and thumb drive but no power. I was trying to work-out how to use a switch or relay or something to switch between otg and power but i haven't came up with anything yet.
treetop777 said:
Nice setup! :good: That's exactly what i want to do. I can connect a mouse and thumb drive but no power. I was trying to work-out how to use a switch or relay or something to switch between otg and power but i haven't came up with anything yet.
Click to expand...
Click to collapse
Hi everyone,
I had same problem!
My pad is rooted, 20b, stock kernel, Finally, find out solution.
I bought IBUFFALO usb with AC power around 15USD. 4 Slots for USB 2.0 and 1 double micro usb. Worked with mouse, Bluetooth keyboard, external drive with USB 2.0 only, usb 3.0 not work. Just for your info.
treetop777 said:
... I was trying to work-out how to use a switch or relay or something to switch between otg and power but i haven't came up with anything yet.
Click to expand...
Click to collapse
Difference between normal and OTG USB cable is that OTG has pins 4 (sense) and 5 (ground) shorted and on regular cable pin 4 is not in use. If you put a switch between these two pins you can switch between regular USB cable for charging and OTG for connected devices.
Some apps can be found on Google Play Store that claim to be able to switch between or enable simultaneous OTG and charging, but most are for specific devices or group of devices, none for G Pad 8.3. Most promising is maybe Faux123 Kernel Enhancement Pro (3.77€ and requires Root+Busybox+SuperSU).
Too bad our tablet has no secondary charging port (like Sony has magnetic charging port for example), but least intrusive would be to use powered USB HUB, let it power the connected devices so the battery drain on the tablet will stay low.
Iknownot said:
Difference between normal and OTG USB cable is that OTG has pins 4 (sense) and 5 (ground) shorted and on regular cable pin 4 is not in use. If you put a switch between these two pins you can switch between regular USB cable for charging and OTG for connected devices.
Some apps can be found on Google Play Store that claim to be able to switch between or enable simultaneous OTG and charging, but most are for specific devices or group of devices, none for G Pad 8.3. Most promising is maybe Faux123 Kernel Enhancement Pro (3.77€ and requires Root+Busybox+SuperSU).
Too bad our tablet has no secondary charging port (like Sony has magnetic charging port for example), but least intrusive would be to use powered USB HUB, let it power the connected devices so the battery drain on the tablet will stay low.
Click to expand...
Click to collapse
Thanks for that - Very good info! Allow me to pick your brain a little more: Looking at the cable i have (in the OP), do you think that by just connecting an external power (red and black) to the cable just before going into the tab would work somehow to give it power.
It's intreging what you said about being able to switch from regular USB (that can supply power) to OTG just by jumping those wires. I'm trying to picture something in my mind to accomplish what we want but the "light bulb" haven't came on yet - any suggestions?
I want to use the tab in the car PERMANENTLY so i need a way to charge it while behind the dash. I would want to use a mouse as well so OTG is a must.
In any case, i'm going outside right know to split open that cable and see how it's connected inside, maybe then the light bulb will come on in my head.
treetop777 said:
Thanks for that - Very good info! Allow me to pick your brain a little more: Looking at the cable i have (in the OP), do you think that by just connecting an external power (red and black) to the cable just before going into the tab would work somehow to give it power.
Click to expand...
Click to collapse
Try it out, you got the cables!
When pins 4 & 5 get shorted the tablet may be configured only to output power, not receive it. I have only OTG adapter cable and the supplied USB charging/data cable, so I cannot test this stuff.
treetop777 said:
It's intreging what you said about being able to switch from regular USB (that can supply power) to OTG just by jumping those wires. I'm trying to picture something in my mind to accomplish what we want but the "light bulb" haven't came on yet - any suggestions?
Click to expand...
Click to collapse
I would buy micro USB male plug, some heat-shrink tubing with glue, switch (3A) and split OTG adapter or HUB. Cut off the male plug fom the adapter, solder on the new plug to the adapter cable as normal USB, solder on the switch to pins 4 & 5 of the plug, check it for continuity and shorts, test it on the tablet, if good - secure the new plug to the cable with heat-shrink tubing.
EDIT: Possible solution with resistor described here
Our device, if it can be tricked this way, may require different resistor from the one used in the tutorial (usually in 36KΩ-200KΩ range).
Ok, I'm chopping it up! I spliced-in the red and black wires from a USB cable into the OTG cable (in the OP) and sure enough the tab gets power. However, it no longer detect the mouse or any thing else (kind of expected). Tomorrow i will try bridging pin 4 and 5 and see what happens. If that don't work, i will try the resistor. :fingers-crossed:
I have read that devices on OTG get polled regularly, but charging is not, i.e. if you start charging and after that short the pins 4 & 5, it will continue charging and you can use your OTG devices. Hope this holds true to the G Pad as well.
Isn't micro USB a "standard"....??
Then GEEZZ why do one manufacturer thinks it's ok to eliminate a pin completely! i assume that when i pay for that cable, i will get ALL 5 PINS even if one is not connected - rip-off! :laugh: This manufacturer not only didn't connect pin 4, it was eliminated completely; stopped me in my tracks! Fortunately, i have an extension that have of all things ALL 5 WIRES CONNECTED! Imagine that! But now, i don't have any time to chop-it-up until tomorrow. With the 5 wire cable, i will short the yellow and black wires but I'll check here first to see if I'm warned against it.
More to come..
Hi manny your car kooks awesome. I have one question. How you connect your speakers from the car with the G Pad. iam also interested to built a GPad in the car !
Sent from my GT-I9505 using xda app-developers app
Yep weneed more info on this as i would like to fit my pad in the van,, how did you get fm radio on there.
Nothing good to report. Connecting the power wire to the OTG cable and shorting the 4&5 pins does nothing different. I can have it charging and when i disconnect power, it then detects the mouse (that's a good thing) but when i plug the power back in, nothing happens! Ideally it would disconnect the mouse and start charging again but no-go. Having the 4&5 pins shorted or not makes no difference.
Still have a couple things i will try before i give up, one is the resistor and the other is a more simple OTG cable.
Will report back.
treetop777 said:
Nothing good to report. Connecting the power wire to the OTG cable and shorting the 4&5 pins does nothing different. I can have it charging and when i disconnect power, it then detects the mouse (that's a good thing) but when i plug the power back in, nothing happens! Ideally it would disconnect the mouse and start charging again but no-go. Having the 4&5 pins shorted or not makes no difference.
Click to expand...
Click to collapse
I understand that you would want the cables all hidden behind the dash in a car and can't be connecting and disconnecting plugs all the time, at the most just flip of a switch should make things work. The resistor trick would be ideal, if it works.
What's the exact sequence you did things in?
- Mouse and charger connected to the tablet simultaneously with pins 4 & 5 not shorted, tablet charging - short pins 4 & 5 - what happens?
- Only charger connected, pins not shorted, short pins and then connect mouse...
- Mouse and charger connected to the tablet simultaneously with pins shorted, mouse working - unshort pins...
- Only mouse connected, pins shorted, unshort pins and then connect charger...
Iknownot said:
I understand that you would want the cables all hidden behind the dash in a car and can't be connecting and disconnecting plugs all the time, at the most just flip of a switch should make things work. The resistor trick would be ideal, if it works.
What's the exact sequence you did things in?
- Mouse and charger connected to the tablet simultaneously with pins 4 & 5 not shorted, tablet charging - short pins 4 & 5 - what happens?
- Only charger connected, pins not shorted, short pins and then connect mouse...
- Mouse and charger connected to the tablet simultaneously with pins shorted, mouse working - unshort pins...
- Only mouse connected, pins shorted, unshort pins and then connect charger...
Click to expand...
Click to collapse
I would have to record in what sequence i do things to remember but it seem i have done every combination possible. I do remember doing these sequences after a fresh reboot of the tablet and BTW i made a simple cable out of a know working (single) OTG cable and splicing-in the red and black from the cable that has 5 wires connected, leaving the pin 4 wire disconnected and extending a pigtail from the black wire so i could short the yellow and black to hopefully force OTG:
- Power plugged in and mouse plugged-in then plug the cable into the tablet - it detects the mouse but does not charge.
- in the above state, shorted the yellow and black wire - no change.
- separated 4/5 then disconnected the mouse leaving power connected (expecting that the tab will then switch to charge but) - nothing. The mouse did disapear but the tab did not start to charge.
- shorted 4/5 (for ****s and grins) and as expected - nothing.
Again with a fresh tablet:
- with (ONLY) power connected to the cable, inserted the cable into the tablet - it started charging.
- in that same state, connected mouse - mouse was NOT detected but the tab continued to charge.
- with mouse plugged in, shorted 4/5 - no change (charging but no mouse detected)
THIS IS THE IDEAL SITUATION BUT JUST HALF WAY:
Rebooting the tablet with both power and mouse connected and cable inserted, the tab starts by accepting the charge (no mouse) but get this, plugging-out power makes the tab switch to the mouse right away! That would be good except that plugging the power back in does NOT make the tablet switch back to power, in fact, nothing happens, the mouse just continues to be detected.
If i had 2 cables, one only for power and the other only for OTG, i could pull one out and replace it with the other and both functions would work; i don't understand why that same "switching" can be recreated within one cable??
This is beyond me, the last thing i will try is following your sequences to the letter and with the resistor, if that doesn't work - i give up! :crying:
budalageo said:
Hi manny your car kooks awesome. I have one question. How you connect your speakers from the car with the G Pad. iam also interested to built a GPad in the car !
Sent from my GT-I9505 using xda app-developers app
Click to expand...
Click to collapse
i have buy a Sony mex bt4000U ... http://www.sony.it/support/it/product/MEX-BT4100U
install in rear a Tablet.. http://www.youtube.com/watch?v=5Y1QXAsSUtc
and work whith APP REMOTE http://www.youtube.com/watch?v=AEfG3Zdf7HM
---------- Post added at 11:02 AM ---------- Previous post was at 11:00 AM ----------
I have used this !!
have disassembly and install !!! work whit switch !!
http://www.ebay.it/itm/231182187439?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

In Car issue: Turning up subwoofer resets tablet USB port

I have a strange issue after installed my Nexus 7 as a car stereo setup in my Subaru (see setup blow)... Whenever I turn up the volume, specifically the subwoofer, the USB system basically "resets" itself. As if, I unplugged and plugged it back in very quickly. At first, I thought my USB DAC was bad, because I plugged my audio feed directly into the tablet with no USB devices connected and all worked fine, but if I have my hub plugged in and then the reset happens (with audio from tablet still), the reset still happens and my OBD2 adapter (USB) brings up torque. I plugged that same USB DAC directly in, with no hub, to my OTG cable and used its audio feed, same issue. I thought maybe the voltage drop was too harsh and causing issues with my charger, so I ran a 120v usb charger setup (like a factory phone one) with an extension cord to my vehicle to isolate its own charge system to the tablet with the same results. OK, Maybe it is just vibration? (forgot to note: subwoofer is freeair, laying in the back seat... still testing, box isn't done yet, so the vibration level is next to nothing currently.) I grabbed my usb cable system with the volume low and shook the life out of it... never did the reset. Again, only when the subwoofer volume goes up and anything is plugged into the USB port on the OTG for external devices does this ever happen.
The Setup:
I have a dedicated 4A 12v-5v charger and it seems to charge the tablet fine. I have a 90 degree charge adapter in place. I also have an OTG Cable so I can hook up USB to my dedicated USB hub that I have a "backup" power cable plugged in (into the same 5v charger the tablet is).
Audio chain wise, I have plugged into my USB hub a USB DAC. After that, a noise blocker. From there, I wired in a potentiometer for volume control. From there, it goes to the 4 channel amp and the mono subwoofer amp (which also has a dedicated volume controller that came with the amp)
Power wise, I have a dedicated run of "oversized 4awg" (basically, 6 awg wire) from under the hood and no more than 5' of cable to a fused distribution block, then to the amps. I also have a ground wire of the same size that from come the battery ground that all amps connect to (as well as chassis, so about an overkill of a grounding system). The factory wiring harness was spliced into for connection to a relay that feed from the constant on factory wire, feeding the 5v usb charger and the remote turn on trigger for the 2 amps (so it shouldn't be overloaded at all).
Items (can't give links, so giving exact item name):
4A 12v-5v charger(Amazon - Icstation LM2596 DC to DC Voltage Regulator Dual USB Charger Step Down Power Supply Buck Converter 6-40V to 5V 3A DC 5.5X2.1mm Port )
90 Degree USB adapter(Amazon - Micro USB Extension Cable - Riipoo Left Angle Micro B USB Extension Cable, 25 CM, Micro USB 5 Pin Male to Female, Sync Charging and Data Transferring Cable for Samsung, HTC, Huawei, Sony and More)
OTG Cable (Amazon - DSYJ Micro USB Host OTG Cable with Micro USB Power for Samsung S7 S7 Edge, S6 S6+ S6 Edge, S5, S4 & Nexus 10 9 7 4 Player + ALL OTHERS )
USB Hub (Amazon - UNITEK Portable USB 3.0 4-Port Ultra Slim Data hub, with Micro USB 2.0 Power port and Built-in USB 3.0 Cable LED for iMac, MacBook, MacBook Pro, MacBook Air, Mac Mini, Chrombook, Surface Pro )
USB Dac (Amazon - Fiio K1 Portable Headphone Amplifier&DAC and USB DAC, Titanium)
Noise Blocker (Amazon - Mpow Ground Loop Noise Isolator for Car Audio / Home Stereo System with 3.5mm Audio Cable (Black))
Potentiometer: (Amazon - 10K Audio Taper Stereo Potentiometer 1/4 Shaft)
4 Channel Amp: (Amazon - Audiopipe 4 Channel Micro Amplifier 1000 Watts)
Subwoofer Amp: (Amazon - Audiopipe Class D Micro Amplifier 500 Watts)
I'm pretty stumped at this point. Any ideas?
Wiring can be a *****!
You could replace your right angle cable and OTG with this one item: https://www.amazon.com/gp/product/B00NSBVNCM/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
My USB3 hub works pretty good. but it's not at rock solid as the USB2 hub it replaced. Hubs can do some weird things when they don't initialize when the tablet want or thinks they should.
How does the subwoofer volume knob connect?
Does the the same happen when you turn the other "volume knob"?
How are the 2 amps connected to the DAC?
I'd guess offhand the DAC doesn't like whatever "feedback" it's getting through the noise suppressor from the potentometer.
What's the reason for it? You should be able to adjust your system volume through the tablet, especially if the sub amp has it's own gain.
fr4nk1yn,
-Just ordered that OTG cable. Was going to try and make my own, but if that one is proven, good enough for me.
-Agreed on hub, but I did try going direct to OTG cable, bypassing hub, and had the same issue.
-Subwoofer volume knob has its own RJ-11 phone cable to the amp. I took it apart, its using only 2 wires out of the 6 to the potentiometer inside, so pretty simple. Not sure how it works at the amp itself, but standard subwoofer volume knob on an amp, far as I can tell.
-Other knob can be cranked, seems fine, but more testing would need to be done. Soon as subwoofer knob is cranked with the volume know all the way up (or close), it triggers really quick.
-Does Dac > Potiometer > Amps (soldered wiring together, 4 channel amp has 2 specific connectors and sub has pair of RCA)
-Potentiometer gives a much better feel, very response in comparison. Having to find a volume "knob" on a tablet requires vision, taking away from the driving experience (and safety!). Don't like if the tablet has ANY delay in that control as well. I'm just old school, I guess.
Thanks for the help!

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