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How to Turn an LG V20 into a dedicated DAP (and general owners' discussion)

pwjazz

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#1
I use an LG V20 as my main phone and love the sound quality and user experience when running Neutron Player. It's got enough power for my full size cans yet remains quiet with my IEMs. Compared to every DAP I've tried, having a modern Android OS provides a much better user experience, and it's nice being able to consume streaming videos in addition to audio.

Unfortunately my LG V20 falls short of perfection in two critical ways:

1. I use EQ extensively for my headphones and would prefer to have system-wide parametric EQ available rather than being stuck with Neutron's in-app EQ
2. When doing focused listening in the evenings, I don't like having distractions available on my player. I lack the self control to avoid them.

Viper4Android FX provides a solution for system wide EQ, but it requires rooting which I'm not willing to do with my primary phone. Since V20s are so cheap nowadays, I decided to just buy a 2nd one to set up as a dedicated DAP and experiment with it. It turned out to be an even bigger pain than I expected, but ultimately proved successful. I've got system-wide parametric EQ that works with most apps (Spotify, YouTube, etc.).

20191118_202628.jpg


In case anyone else wants to try this out, I'm sharing my notes on how to make it happen.

Disclaimers
  • This is a bit of a pain in the butt
  • You run the risk of making your phone permanently inoperable
  • My instructions are for the H910 (AT&T) variant of the V20. It's possible they could work with other versions, but I can't say for sure

  1. Buy a V20 H910 like this one on eBay. They're still available New in Sealed Box. I paid about $120 for mine
  2. These things are slippery, so you'll want at least a minimal case to make it easier to hold on and protect it if it drops. A case like this one is cheap at around $8, affords minimal protection, leaves enough clearance to plug in most 3.5mm jacks without a problem and can be taken on and off quickly which is important because you'll need to remove the back cover of the phone to swap out sd cards
  3. A stand like this $8 one makes for a nice little listening station
  4. You'll need a microsd card with at least 4GB of storage (maybe more). I have plenty lying around so I used one that I had on hand.
  5. Follow these instructions to prepare the V20 for rooting. This involves installing a "custom recovery" called TWRP which allows you to overwrite system files while in recovery mode. When you're done, you'll be running an AT&T build of Android 7.0 Nougat and TWRP custom recovery installed.
  6. Install Magisk Manager using these instructions. When you're done, you'll have a rooted phone, meaning that applications can request and obtain root access through Magisk. Magisk Manager also allows you to download and install various useful applications.
  7. Install and run ViPER4Android_FX_v2505_A7.x_Nougat_IO_test_fix.apk. Inside the Viper4Android app, choose to install the driver. This should prompt you for root permissions in MagiskManager, but I noticed that sometimes it's a bit slow so you might have to go into MagiskManager manually, grant root to Viper4Android, then restart Viper4Android and install the driver again.
  8. At this point, your system is in a weird state. Viper4Android will have failed to install the driver. That's okay, just ignore it for now.
  9. In Magisk Manager, install these three modules -- a) Audio Compatibility Patch v1.7.3, b) Audio Modification Library v2.4 and c) ViPER4Android FX Legacy Materialized v4.4. IIRC I just accepted all of the recommended options during installation. This Viper should replace the one you installed earlier.
  10. Open Viper again and install the driver and restart your phone
  11. At this point, Viper's driver should be successfully installed and you can start using it. I had a lot of trouble getting Viper4Android to work, but I stumbled on this sequence by accident and for whatever reason it works.
If anyone tries this and finds corrections for my notes, please let us know and I'll update my post accordingly.
 
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pwjazz

pwjazz

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Thread Starter #2
I should note that in order to use parametric EQ, you'll have to create DDC files and copy them to /storage/emaulted/0/ViPER4Android/DDC/

You can use DDCToolbox to do this. I was able to compile and run this on Ubuntu 18. YMMV.

It's a bit cumbersome, but it's actually kind of nice having the EQ profiles as files since those are easily backed up.
 

Cahudson42

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#3
@pwjazz
Thank you for your great HOWTO. Question: Item 6 Magisk. Install. Is 'these instructions' supposed to be linked to somewhere? Looks like plain text.

Suggestion: If not a thread elsewhere, might you consider changing title to include 'and Owners Thread'. Your posts are a great start for one.

My V20 H910 arrived today. Like yours, sealed NIB $120.

I am not sure if I will root it yet, as my original plan was to use it with an NX3s, as it's high impedance shouldn't effect my HE400i. Already have the NX3s @$55, so will try that first after everything is charged.
Thanks again!
Chris

Edit/Update 11/20

Well, the NX3s, IMO, appears to work well with the V20 Quad DAC. Plenty of volume - and headroom - with HE400i, even with the NX3s in low gain mode..

This using Amazon Music HD, the only player I use.

Looking at the V20 for $120, and mentally comparing it to my alternate Fire 7 tablet ($30) and OTG cable driven D10 ($90) I'm wondering, if starting from scratch, which is the better setup for $120?

Sitting next to the V20, the D10 appears a gigantic beast.. obsolete beast maybe. The D10 also is very noise and cable sensitive - it continually clicked and reset until I used decent shielded output RCA cables, and a clean 5v USB power brick. It also needs the power brick to function at all. While the V20 has either battery or it's USB supplied power...

Both the V20 and Fire 7/D10 drive external amps just fine. The V20 the NX3s, and the D10 a Liquid Spark (the LS does have more power than the NX3s, but I see no reason I couldn't use the V20 to drive the LS for desktop use..)..

All in all, for an Amazon HD Music player, I have to conclude, for $120, the V20 is a better choice than my Fire 7/D10 setup. Now a question - how good is the DAC in the Fire 7?? How does it compare to the V20 DAC?

Hopefully, Amirm will test a $30 Fire 7 soon...
 
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pwjazz

pwjazz

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Thread Starter #4
Is 'these instructions' supposed to be linked to somewhere
Yup, fixed. It was supposed to be https://www.xda-developers.com/how-to-install-magisk/

According to this, the LG V20 should be plenty capable of powering the HE400i in its high impedance mode. If you think you might want to root, you can trick it into high impedance mode before rooting it to see if you like the result.

1. Plug the HE400i into an impedance adapter
2. Plug the impedance adapter into a short 3.5mm extension cable
3. Plug the extension cable into the V20
4. Check to make sure it triggered high impedance mode
5. Remove the impedance adapter and plug the HE400i straight into the extension cable
 

Cahudson42

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#5
@pwjazz Thanks again! Quick question? My V20 has 'Enable Quad DAC' with only Balance and Volume subsettings. No 'filter' like Amirm showed for the G7. Is your V20 also missing those, or might I have an out-of-date system software version?

Android 8.0
Ketnal 3.18.71
Build 170623.032
Software H,920h

I have a ATT Trek K88, and it will only update when a valid ATT sim card is installed.

Does the V20 only update that way, with a valid sim card?
 
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pwjazz

pwjazz

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Thread Starter #6
@pwjazz Thanks again! Quick question? My V20 has 'Enable Quad DAC' with only Balance and Volume subsettings. No 'filter' like Amirm showed for the G7. Is your V20 also missing those, or might I have an out-of-date system software version?

Android 8.0
Ketnal 3.18.71
Build 170623.032
Software H,920h

I have a ATT Trek K88, and it will only update when a valid ATT sim card is installed.

Does the V20 only update that way, with a valid sim card?
The V20 doesn't support user selectable filters.

I've rooted my H910 so I definitely don't get OTA updates. It's plausible that a SIM is required.
 

Cahudson42

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#7
Thanks again to @pwjazz , I just tried the impedance adapter amp reset method for low impedance headphones...It works great!

I did get the 220ohm adapter..
FAAEAL Conductor Earphone Impedance Plug 80 220 ohm Noise Cancelling Adapter 3.5mm Jack Professional Reduce Noise Filter Plug (220 Ohm) https://www.amazon.com/dp/B07FM8GJL4/

and this 3.5mm extension:
Josi Minea x 2 Pcs 3.5mm Red Headphone 1 Feet Long Extender Adapter 3 Ring Jack for Apple iPhone/iPad, Samsung Galaxy Note & Phones and Most Smartphones & Tablets [ 1 Feet / 30 cm - 2 Pack ] https://www.amazon.com/dp/B013I1N1QM/

Following his instructions, I plugged the adapter into the extension, and then my SHP9500 into the adapter. Plugged the male extension into phone. (It was on. It then popped up the 'hifi' symbol as it switched to the Quad DAC). Leaving extension plugged into phone, removed impedance adapter and plugged headphones into female extension.

Result, 'ear shattering' clean volume with the SHP9500 at '52' on LG volume scale. Switching to HE400i, same at '62'.. Outstanding IMO !

Looks like I don't really need the NX3s. I do think my Liquid Spark does give a bit more 'perceived' dynamic range and 'deeper, fuller' bass (sorry for the subjectiveism:) ) but the difference is not very much...

For now, I don't find using the adapter inconvenient, and don't plan to root. I only use the V20 as a DAP, so I can set it with the adapter, and 'forget it'...

Thanks again @pwjazz
 
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Cahudson42

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#8
Check to make sure it triggered high impedance
May I ask how to check if it's in 'line out' or 'high impedance' mode?

Update/Answer - in the V20, in Settings, Quad DAC, subsettings, it appears to show 'external device' when in 'line out' mode. In 'high impedance' mode, it shows, more logically, 'high impedance'..

Also, I finally waded thru the 13 pages on amirm's original G7 review. Found this from @Michael :

" I figured out how Amir got 2.0 V-RMS. In "High Impedance Headphones" mode, you get 2.0 V-RMS. in Auxiliary mode, which is what you get when you plug your phone into a headphone amp, you get 1.0 V-RMS. In order to get that "High Impedance Headphones" mode, you have to load the output of the phone with 50 to 600 ohms, on each of the two channels. Any higher, you get Auxiliary mode. Any lower, you get the regular headphones mode."

This means something. Those of you plugging in an adapter to trick the phone into high impedance mode aren't getting it. You're getting auxiliary mode, which is 1 V-RMS. If you want high impedance mode (2 V-RMS), you have to make an adapter with a load on each channel, then disconnect the load after you get your headphones connected - kind of difficult..."

If you want the status displayed as an icon, there is a 0.99$ app 'hifi status (LG)' in Google play store..
 
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raif71

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#9
Hi @pwjazz , I plan to follow your instructions and making the V20 a dedicated DAP Android player. Question, when I get the V20, should I update to latest OS version before rooting it? Or it doesn't matter?
 
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pwjazz

pwjazz

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Thread Starter #10
Hi @pwjazz , I plan to follow your instructions and making the V20 a dedicated DAP Android player. Question, when I get the V20, should I update to latest OS version before rooting it? Or it doesn't matter?
Short answer-don't bother upgrading.

I did not upgrade, but my phone already came with Android 8 which AFAIK is the most recent published by AT&T. If you follow the same rooting procedure as I, you'll end up with Android 7.
 

tential

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#11
To my knowledge, all this root does is add system wide eq.

It doesn't add system wide bit perfect playback correct?
I only want a dap for that reason. If I can hack a v20, I'm all for it. If I can make it work with an e1da natively better!
 
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pwjazz

pwjazz

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Thread Starter #12
It doesn't add system wide bit perfect playback correct?
If you want that, you can get close to it with rooting. See https://forum.xda-developers.com/v20/themes/increase-lg-v20-hi-fi-dac-quality-t3724489.

Note that:

1. This does not work with Viper4Android, so you have to choose between either system-wide EQ or bit-perfect playback
2. IMHO the concerns about resampling in the Android mixer are overblown. As long as the signal is actually being handled by the good DAC, the V20 sounds great.
 

tential

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#13
If you want that, you can get close to it with rooting. See https://forum.xda-developers.com/v20/themes/increase-lg-v20-hi-fi-dac-quality-t3724489.

Note that:

1. This does not work with Viper4Android, so you have to choose between either system-wide EQ or bit-perfect playback
2. IMHO the concerns about resampling in the Android mixer are overblown. As long as the signal is actually being handled by the good DAC, the V20 sounds great.
Thanks a lot for this info.
I think that's great but I also don't need system wide parametric eq that you have to make the profiles for.
So I'd rather just have the system wide bit perfect playback, since if you go through the resample you reduce SINAD.

Also, does it output to dac with system wide output like the e1da? That's basically all I need.
 

raif71

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#14
If you want that, you can get close to it with rooting. See https://forum.xda-developers.com/v20/themes/increase-lg-v20-hi-fi-dac-quality-t3724489.

Note that:

1. This does not work with Viper4Android, so you have to choose between either system-wide EQ or bit-perfect playback
2. IMHO the concerns about resampling in the Android mixer are overblown. As long as the signal is actually being handled by the good DAC, the V20 sounds great.
After reading further this thread, I may not go for Viper4Android. If that is the case, before rooting again I ask the question, should I update the phone OS or again it doesn't matter ie after rooting updating is still possible? Also I have been reading about AT&T mentioned quite a bit in the instructions, understand that I'm not in America...so hopefully after rooting the phone can still connect to my local cell vendor ? Thanks for your help
 
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pwjazz

pwjazz

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Thread Starter #15
After reading further this thread, I may not go for Viper4Android. If that is the case, before rooting again I ask the question, should I update the phone OS or again it doesn't matter ie after rooting updating is still possible? Also I have been reading about AT&T mentioned quite a bit in the instructions, understand that I'm not in America...so hopefully after rooting the phone can still connect to my local cell vendor ? Thanks for your help
Once you have rooted you will not be able to get carrier provided OS updates.

Whether or not the H910 can work on your local network depends on what frequencies and protocols they use versus what AT&T uses. It's quite possible that you can make calls but that days speeds might be limited.

If you intend to use this as your phone and not just a DAP, I would advise against rooting.
 

raif71

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#16
Once you have rooted you will not be able to get carrier provided OS updates.

Whether or not the H910 can work on your local network depends on what frequencies and protocols they use versus what AT&T uses. It's quite possible that you can make calls but that days speeds might be limited.

If you intend to use this as your phone and not just a DAP, I would advise against rooting.
I intend to use the v20 as a dedicated DAP so, if I understand you correctly then I better update the OS (to get as many fixes) as after rooting, I'm not able to do that, right?
 
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pwjazz

pwjazz

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Thread Starter #17
I intend to use the v20 as a dedicated DAP so, if I understand you correctly then I better update the OS (to get as many fixes) as after rooting, I'm not able to do that, right?
The rooting process involves downgrading the OS, so there's no benefit to updating before rooting.
 

Degru

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#20
The problem with using Viper is this limits you to Android's sub-par audio system, which is 16-bit and resamples audio to 48khz using a low quality algorithm (though something like Neutron can partially work around this with its own internal resampling).

As far as dedicated DAP use goes, just using Neutron with the "display player UI on lock screen" option enabled is rather fantastic. You can use the entire app without unlocking the phone, and it supports outputting bit perfect to the internal hi res dac as well as any usb devices.
 
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