Walnut Hi-Fi V2 WAV (& MP3) Player by wt - :ok_hand: screenless budget killer combo DAP/Amp :ok_hand:
Dec 8, 2016 at 4:21 AM Thread Starter Post #1 of 3,631


Member of the Trade: bhobuds.com
Aug 14, 2006
This thread is dedicated to the Walnut V2 WAV Player. I have never owned the previous version Walnut DAP and found out about this from the Obscure Chinese DAPs thread. Like the Zishan DSD, this DAP has been gaining popularity fast - and for good reason. As such I decided to make a thread to centralize discussion on this wonderful budget DAP. I will eventually complete this as well as the 2nd and 3rd posts with more information to help out new, old and potential Walnut owners.
WAV Player designed by wt

Supports MP3 and WAV up to 16-bit, 48KHz sample rate
Functions either as DAP or headphone amp
Uninterrupted playback, remembers song position between power cycles
Socketed opamp (comes with TI NE5532)
16V power supply for exceptional dynamics and energy
Reads from microSD storage in realtime
Charges by microUSB, 40+ hour battery life  - 1500mAh battery
3.5mm headphone and line out/line in combo port
Digital & analog volume controls
High end capacitors used
Dec 8, 2016 at 4:21 AM Post #2 of 3,631
The player can be bought for under $30 USD shipped, proving that high sound quality and premium features (dual mono DACs, socketed opamp, 16 volt power supply, high end capacitors) do not necessarily command a premium price. I have been blown away by the transparency and detail of this DAP to the point where I have been using it nearly all day long, as the sound is so sweet. I have almost no desire to use any other gear with it around as it only rivals the very best gear combos I own, and for a ridiculously low price. Because of the barebones design, battery life is far above average for a DAP.
It is listed in the title as a DAP & amp as the player can, in fact, be used as a portable amp by itself. 
 To turn the amp mode: boot automatically start playing music, then press the pause button, you can enter the amp mode, LO input port for the PO output, connected as shown (proposed to open the key lock to prevent misuse).

Power output measurements will be posted when I get a chance to do them. If anyone else is willing to measure theirs, i would be more than happy to put their findings here and credit them. If not, please wait for my measurements to replace this message. 
Specs (written/compiled by me):
  1. Supports MP3, WAV up to 16bit
  2. Socketed opamp (stock is NE5532 or OPA)
  3. microSD slot
  4. microUSB charging/firmware update port
  5. Headphone and line out 3.5mm connectors
  6. Previous, play/pause, next buttons
  7. Digital volume control (hold previous or next button down) as well as analog volume control to perfect volume range to your needs
  8. 1500mAh  battery, 16v power supply for greater dynamics and lower noise - over 24 hours battery life!
  9. High quality capacitors used only (Ina SILMICII, ELNA)

Recommended stores (best results from head-fi members)
I got mine from CKLewis on AliExpress. they include a 8gb card (questionable reliability of microsd but you have to know it's cheap)
THIS IS OUTDATED! Mistertao is no longer in business. Use TAOBAORING or some other Taobao proxy instead.
1. Find the items you want to buy.
Mistertao supports either browsing style (like Aliexpress, Amazon, etc) or directly going to Taobao links. If you already know your item by its Taobao page - for instance here is the Walnut's - you can copy and paste the taobao URL into the search bar and you will see the item you want translated into English.


2. Check out once you have everything in your cart.
Mistertao is a forwarding service which means they buy your items on Taobao for you, ask the seller any questions you want to know, and ships the stuff to you after they get it. The way it goes is you pay for your items during checkout as well as shipping within China, Mistertao orders them for you, and when everything makes it in, they re-package it, weigh that package for you, and tell you how much it's going to be to ship it to you. Then you pick your method of shipping from China, do the second payment (shipping fee + small commission), and they will send it.

You can see here the "add money" button - they like it if you put in a ton of money and use it up, since you don't make direct payments every time but rather fill up your Mistertao balance and use that to buy your stuff. What I did to not have extra money sitting in Mistertao was to only add money during the checkout process and only the exact amount I needed to pay. I picked the Credit Card processing service with the lowest fee (three are available, one seems to be primarily Russian - they all look sketchy but are safe to use, I have several times) 
3. Wait for your stuff to get in
Now you can go to your account page to watch your order and the status of it being purchased, received, and repackaged for shipping. This is a screenshot of an order that has been completed with its second payment and has been sent to me. You will get an alert by email when your last thing makes it in to the Mistertao facility, and shipping has been calculated to your destination.

(The "shipped" status means second payment has been made and it's been sent to you. I don't have any screenshots from when it was processing)
4. Pay the second payment (shipping from China to you) and wait!
Once you are notified that it is time to make the second payment, you'll be able to use Mistertao's shipping calculator to find out the best option for you. You will be told how much you owe for commission (less than $3 on a $50 order I made) and shipping, so you can easily add that exact amount to your Mistertao wallet. Note that by default it is set to automatically make needed payments when you add money, so it should automatically pay your second payment for you. If it doesn't then simply press the "pay" button.
The shipping calculator is awesome and lets you plug in your order amount so you can know exactly how much you'll be spending.
NOTE: Singapore Post ships registered mail and as such a signature is required for delivery (at least in the USA!)


That's all there is to it. It is pretty simple. Just don't forget to make your second payment when you have to and it will be all good =)
vapman - 4.5 Stars
I will collect the opinions of other Walnut users here. As the Walnut uses primitive FAT32 support (only the order the files are copied to the card is obeyed) so you can use a FAT32 sorting program to re-arrange your files for how they will be played back.
 Many have excellent luck with foobar to do everything from converting from and to any sort of file and file structure and properly removing all ID3 tags. However other software is encouraged by users and recommended software by multiple people can be added here.
Another option is Total Commander which allows you to queue copies allowing you to copy the files in the exact order you want. I also use dbPowerAmp Music Converter's Windows Explorer plugin to quickly remove metadata from all wavs to prevent static at the end of the song.
  • Charge before first use. The Walnut V2 ships with about 25% battery charge. This is low enough that it is possibly detrimental to battery life to fire it up and go. Plug it into a USB charger and wait until the light turns from red to yellow to signify a full charge. It doesn't hurt to let it charge a bit longer before first use. (I did for an extra 2 hours, and i'm getting over 24 hours battery life, don't know about others...)
  • Convert your FLAC/Apple Lossless/etc to WAV (16-bit, 44.1khz - 16/44.1, 16/48, and 24/48 tested by me personally 24bit will not play!).
  • Strip the metadata from the WAVs. Information like album art, ID3 tags, etc are not processed by the Walnut. It will instead make nasty quick white noise bursts at the end of each of your songs. Removing all the ID3 tags and album art fixes this. There are many tools to properly clear the WAVs of all their metadata, ranging from freeware such as Foobar2000 or Mp3tag as well as shareware such as dbPowerAmp.
  • Copy in order you want to hear your music. The Walnut can remember where you left off when you turned off the player last. As long as you didn't use a different microSD card, you can pick up from where you left off even if you updated your microSD card. It is a first in first out design, so be sure your files are copied in the order you want.
Finding the song you want can be hard when you have a 32GB card full of WAVs and don't want to be pressing the skip buttons for 20 minutes. One trick is to encode your WAVs as a single file, if you don't mind losing the ability to skip individual songs. This practice allows you to skip an album/playlist/etc at a time, saving the buttons and your thumbs from extra stress.
MAKING THE BEST OF YOUR WALNUT (with silicone feet)
The stock opamp is excellent and is arguably the best choice for transparency and detail with a neutral but energetic sound signature. There is not a lot you have to do to make your Walnut better. Unlike most budget products, it doesn't need any mods to be the best it can be. Other opamps are not necessarily better, but are different sounding. The only suggestion I have to possibly offer is silicone bumpons. While the possibility of them absorbing vibration for sound purposes is unproven and basically entirely subjective, I like my Walnut with them on and prevents it from sliding or scratching against other metal. You can get a sheet of 100 for under $7 shipped anywhere.

PREPARING YOUR FILES (With foobar2000)
  1. Output format: WAV, 16bit, leave sample rate as source UNLESS IT IS ABOVE 48KHZ
  2. Destination does not matter and is up to you.
  3. Processing does not matter and is up to you.
  Also, for those of you with metadata woes, don't forget foobar2000 is 100% freeware and does the job perfectly and quickly. Select your tracks, right  click, Properties, tools, remove tags, "OK" !



  the postman finally arrived, and now I have my walnut v2!
I first charged it up like a good boy and then went straight to try out some RMAA unloaded charting.
disclaimer: all DAPs have EQ off, and their volume roughly at 80%, and laptop mic-in at 100%
first up, Walnut V2 with volume pot at 12 o clock position (assuming off is at or close to 6 o clock position), this is so loud that I had to adjust my laptop's mic-in volume to 20% from 100% to avoid clipping.

next, Walnut V2 with volume pot at 9 o clock position (mic-in volume back to 100%), does this mean I get a channel imbalance at 9 o clock position?  however, I am not hearing any channel imbalance like the chart shows.  and as a reference, the 'nut at 9 o clock is same loudness as my Fiio X3ii volume at 60 mark.

next up, Fiio X3ii, volume at 85 mark and laptop mic-in at 100%

next up, AGPTek M20 (aka Benjie S5), volume at 18 and laptop mic-in at 100%

finally, Ruizi X02 (aka AGPTek A02), volume at 3/4 of that full circle, laptop mic-in at 100%

in regards to the Walnut's roll off, unfortunately, I have to say that at comparable volume, and bass quantity and quality aside as I am still not very good at describing sounds yet, my Fiio X3ii has more bass than the 'nut =(
  Walnut V2
DAP, unloaded, and loaded with Pai Audio MR3: (note different scale to fit response to MR3):                     DAP, loaded with other kind of phones:
Amp mode, unloaded and loaded with MR3:

They are unusable for sensitive multi-BA phones.
Unloaded curve is far from being flat. Some people say they remind you 80's players; it must be due to the premature roll-off at both sides, lows and highs, together with a slight mid centric bump. Energetic, but I guess congested as well.
My (inaccurate) measures (@ 1KHz), using DMM (Zishan as source for amplifier mode, 1.874Vrms in-signal):
Output impedance: phones out, 101Ω!!!; line out: >2KΩ.
Max. output unloaded: phones out, 3.328Vrms; line out: 0.333Vrms; amplifier mode, 6.43Vrms.
But measured 4.2Vrms max., before it starts clipping.
Hiss with MR3 is awful; it's like loud metallic machines; it's no hiss, it's pure high noise.
Strange excessive high out impedances, low line out power, and high amplifier power (for the price) up to 4.2Vrms.
But the amplifier, while powerful, is almost unusable. First, the bass roll-off is enormous.
Second, the steps in volume potentiometer; usable volumes are located in a 6th (60º) of the wheel. Start at1.30h, 0.18 at 2h, 0.4 at 2.30h; 3 at 3h, 5 at 4h, 5.8 at 5h, and 6.1 to 6.4 from 6h to 10h (Vrms); so suitable volumes are from 2h to 4h; impossible for volume fine adjusting.
My unit could be defective, after seeing the strange values I got from the measurements; but it sounds like 80's players, I must agree.

Edit: added hiss info

Dec 8, 2016 at 4:21 AM Post #3 of 3,631
WALNUT V2.2 FAQ by vapman

Please do not forget occasional cracks and pops are expected and normal before 20-40 hours of use, after that should never occur.​

There are a few pages worth of excellent information in the "Chinese Obscure DAPs" thread
mainly by @neog007, @T.R.A.N.C.E., & @nick n
concerning early discussion from the "discovery" of the Walnut as well as lots of very useful information of different opamps.
Looking thru that thread's older posts will be a great resource for info on many different opamps in the Walnut V2.


Troubleshooting problems

  1. Loose/weak headphone jack fix, no soldering required -> http://www.head-fi.org/t/828315/walnut-hi-fi-v2-wav-mp3-player-by-wt-screenless-budget-killer-combo-dap-amp/1065#post_13152811

Walnut General & Other Assorted Facts
  1. Why do I want a screenless DAP? Sounds dumb.
This is definitely not the device for everybody! But it is the device for everybody who either used music players before they had screens, wants simplicity and great sound at a low price, or loved the idea of the Tera Player but laughed at its price tag relative to the cost of parts used. But I digress...
  1. It still sounds dumb.
Like I said, it's not for everyone.  
  1. I am an electrical engineer and want to know what's REALLY going on here.
Hopefully this answer will satisfy you. It's a CMOY amp with a gigantic no-joke battery which can either run off a line input or a built in basic WAV/MP3 decoder that runs at 44.1 and 48khz sample rates. And some buttons for previous and next track.... and some LEDs. Yup.
  1. Head-fi user @mgunin asked me to weigh the Walnut by itself.
  2. The Walnut weighs 3.5 oz. This is 0.1oz less than the iPod Mini. (Pic)

  1. There are no firmware updates yet. The developer of the Walnut has not released any firmware files or instructions on how to flash an update, but note the charge port can also flash the Walnut with a new firmware.

Modding / Walnut's output stage
  1. Can I replace the opamp?
Yes. It uses a single dual opamp, 8 pin DIP. The stock is a NE5532 which offers superior clarity and transparency. There is only one on the board. Take note of which way it is facing, evidenced by the small circle on one corner of the IC.
  1. How can I open it?
Remove the Philips head screws from the front panel. The Walnut will then pull out from the front panel.
  1. What opamp should I use to make it sound more ________ instead of the stock opamp's sound?
This is a highly subjective matter so I will refrain from making any statements that appear as more than personal opinion. But, I will say that although I love the sound with the NE5532, I have a second Walnut which I roll opamps in.
My thoughts: OPA2134 or OPA2228 if you want much less bass/more linear signauture but more airy sound but borders on lifeless in comparison to NE5532. JRC4556 for people who want a smoother overall sound, more emphasis on low end and smoother. Non TI Branded NE5532 are known to be superior to the TI 5532 in dynamics and clarity as well as noise floor. Many AD opamps are known to be good too.
  1. What is the true function of the line out port?
The port is necessary if you wish to bypass the amp stage. This is more suitable for connecting a separate amplifier. I never use an amp because the sound of the built in amp is great to me (it is arguably the best variation on the CMOY design to date in my opinion) but it is preferential to the headphone out if I am using a stereo receiver or something similar.

  1. Is it okay to use out of the box or should I charge it first?
Since the Walnut ships with a battery at such a low charge, it's highly recommended you charge it to full before first use. Doing so will ensure you get multiple days of battery life for years to come.
  1. Is it safe to charge whenever I want or should I drain it all the way?
Being a li-ion battery, it's okay if you plug it in without knowing how full the battery is. However, don't leave it plugged in always! If you, for whatever reason, do wish to use it plugged in for power always, consider disconnection the internal battery (2 pin removable plug).
  1. Playback stopped and the instruction light is blinking really fast!
You ran out of battery juice 
 Plug in to usb and wait at least 15 minutes before switching back on!
  1. What kind of charger should I use?
It seems the Walnut can pull around 700mA when charging. A 1A or greater USB charger is recommended. It does not support fast charging, but from empty only takes about 2 hours to charge to full.

  1. What does the flashing yellow light mean?
It just means playback is happening. If you pause it with the "stop" button, you'll notice it goes solid until you unpause it. If you really really hate it, you can cover it up or clip off the LED. It will also blink quickly to indicate critical low battery level.
  1. Is there a way to shuffle the music on the device?
For the time being no such option exists. It's possible it might show up should a firmware update ever be released.
@heraleks found a way to use a FAT sorting prorgram (fatsort)'s -r (random) parameter to randomize the order of files on the drive. You can do this on your microSD card to shuffle the file order. It must be done again to rearrange the files again
  Hi all :) Sorry my googletranslate english)
I just registered here, but for a long time I read this thread. I also have a Walnut and this DAP really great EDC player.
For those who want shuffle tracks (and not only) can be useful 'fatsort' program. It is a command line utility for Linux and Mac OS X. You can use it not only to sort the files but mix them (key -R).
The home http://fatsort.sourceforge.net/
The output of #fatsort -h
FATSort sorts directory structures of FAT file systems. Many MP3 hardware players don't sort files automatically but play them in the  order they were transferred to the device. FATSort can help here.
Usage: fatsort [OPTIONS] DEVICE
    -a     Use ASCIIbetical order for sorting
    -c     Ignore case of file names
    -f     Force sorting even if file system is mounted
    -h, --help
        Print some help
    -i     Print file system information only
    -I=PFX     Ignore file name PFX
    -l     Print current order of files only
    -o=FLAG     Sort order of files where FLAG is one of
            d : directories first (default)
            f : files first
            a : files and directories are not differentiated
    -n     Natural order sorting
    -q     Be quiet
    -r     Sort in reverse order
    -R     Sort in random order
    -t     Sort by last modification date and time
    -v, --version
        Print version information
    The following options can be specified multiple times:
    -d=DIR     Sort directory DIR only
    -D=DIR     Sort directory DIR and all subdirectories
    -x=DIR     Don't sort directory DIR
    -X=DIR     Don't sort directory DIR and its subdirectories
DEVICE must be a FAT12, FAT16 or FAT32 file system.
    fatsort /dev/sda        Sort /dev/sda.
    fatsort -n /dev/sdb1        Sort /dev/sdb1 with natural order.
Report bugs to <fatsort@formenos.de>.

  1. Background noise seems to be getting more prominent.
​I found that ~30 minutes before it stopped playback because the battery was too low, the background noise increased significantly. this is an easy way to tell your Walnut is at low battery.
  1. I want to play my lossy files on it.
As long as they're MP3, and you stripped the metadata, you'll be fine. (If you are lost already, don't worry, the next sentence answers your confusion.)
  1. I hear bursts of static at maximum volume at the beginning/end of some or all of my songs. What's up with that? And what is "metadata" anyway?
You have metadata left over in your WAV files. The answer is almost definitely that you have ID3 tags, album art, or both left over in your WAV files. As there is nothing for the Walnut to do with this information, and because of its minimalistic design, it cannot process this data, and instead tries to interpret it as more PCM data. Thus it is interpreted as sound and you get white noise as a result. You can remove this with many tools that handle ID3 tags. Some are mentioned in post 2.
  1. I checked and there's nothing in any of my tags. I don't get it!
You might be using something like iTunes which doesn't actually delete the metadata but fill in each field with blank space. This might not make noise but will impact gap length between songs. What you need is a tool like dbPowerAmp's included Windows Explorer extension or Foobar2000 if you're on Windows. If you're on Mac OS X, there is an app on the Mac App Store called "Tag Stripper". I have never tried it, and hope to hear if it's a good solution from any of our Mac using Walnutters. If you're using Linux, you should not need your hand held through this! 

  1. My music is not at all in the order I copied it.
Blame your operating system's copy mechanism which favors speed over partition order, since almost nothing in the worst only and solely relies on FAT32 partition tables to tell you where files are. If you are on a Mac, you can try sorting Finder by name and copy one album at a time. If this does not work, the Terminal (cp -rv * /path/to/destination) would do the job as expected. Sorry Mac users if you're scared of the terminal - I'll let Mac users jump in here. For Windows, Total Commander or TeraCopy which both support queueing is highly recommended.
  1. I'm having other crazy glitches. I deleted everything off my microSD card, or it was new when I got it, and can't figure it out.
If you're sure there is no ID3 or album art information left over in the WAVs, and you're still encountering glitches, you could have a messy FAT32 partition table. For both Mac OS X and Windows, you can install SDFormatter, which properly formats any SD card to proper SD specs. If you have a glitchy card - especially if it has had lots of data on it before - it's highly recommended to make sure all old information is gone by overwriting the old data. I have not run into any issues using quick formatted SD cards with my Walnut, but if you are encountering issues, try the full overwrite and "Format Size Adjustment" options. The format will take longer but your SD card will be 100% clean.
  1. The card is clean and I still have glitches!
If your card is really old (class 2 or 4, pre-mircoSDHC, or both) there is a chance your card is too slow for reliable realtime playback. This will probably not be an issue with class 4, but is possible. Class 2 is more at risk. As storage is so cheap these days, a Class 10 32GB card can be had for under $10. Consider using a different card if you have one problematic card.

  1. My headphones are way too sensitive for this, they're too loud and the thing is barely turned up.
The Walnut features digital as well as analog volume control. Hold the previous or next buttons down to control the digital volume. This is actually a great way to either tune the range of the analog knob per every set of headphones you have, or prevent it from being turned way too loud. 
  1. I have high impedance headphones. Can this drive them?
​Yes, this little box is a powerhouse.  I tried it on non-sensitive 650 ohm headphones and it was able to drive them to very uncomfortably loud volumes. Most DAPs can not claim this!!!
  1. I think I am hearing slight clipping or distortion at times.
This is known to happen with very loud mastered material, on brand new units. It can only possibly be heard in these circumstances on a brand new one since they are not broken in at the factory. Run it for a couple days and you'll never hear it again, if you ever do.
  1. The line out port is controlled by the volume knob. 
Yes this is intentional. The reasons for it are unknown but it is what it is. It seems that the signal for both runs thru the volume pot, but the line out actually seems to be a signal directly from the DACs as opposed to running through the rest of the Walnut's circuitry. As such the line out port sounds flat and less energetic compared to the headphone output.
  1. I hear a faint squelch when turning off the unit.
The Walnut lacks a relay. It is recommended to unplug your headphones before turning on and turning off.

Using the Walnut as an amp.
  1. To use your Walnut in amp mode, either turn it on without any microSD inserted, or press "stop" to stop playback. When the instruction light is solid (non blinking), you can insert the input cable to the Walnut's line out jack. Then plug in your headphones.
  2. Walnut will be running at full power, so if your headphones are sensitive, or you always need to use digital volume control with them normally, be careful!!!
  3. Digital volume control does not work in amp mode.
  4. Yes it gets VERY loud.
    1. You don't believe me?



Walnut vs. Other Screenless DAPs
Dec 8, 2016 at 8:34 AM Post #7 of 3,631
Hello, its my first message, i am dont know so many about players and sound, really interesting in this player, just wanna know, did you listen electronic genres on this dac and how good bass and low frequencies? I hope this player deal with good "dark" sound, it is not so matter. Or maybe you can give me advice to buy another player with price between ~70$. I dont ever have player inb4, but have earbuds - ingping h60, soon i will get urbanfun. Thanks
Dec 8, 2016 at 9:09 AM Post #9 of 3,631
Got hyped by your post as well And got one yesterday from cklewis. I wonder if it can drive Zen 2.0 well? If so we would have a killer setup in terms of size and quality. Very excited about this.

I am going to guess yet. the ebay/ali descriptions show the recommended range is 15 thru 300 ohms... zen 2 is 320 and quite sensitive too. so should be good.
Dec 8, 2016 at 9:10 AM Post #10 of 3,631
Hello, its my first message, i am dont know so many about players and sound, really interesting in this player, just wanna know, did you listen electronic genres on this dac and how good bass and low frequencies? I hope this player deal with good "dark" sound, it is not so matter. Or maybe you can give me advice to buy another player with price between ~70$. I dont ever have player inb4, but have earbuds - ingping h60, soon i will get urbanfun. Thanks

yes my Walnut is great with electronic genres. i have eurobeat, ambient. 80s industrial, 80s/90s house and various other techno
in fact only 3 of maybe 15 albums arent?
In fact for a DAP that you can't set the EQ on (is this correct?) it's got very powerful bass, kinda like the sub bass is just slightly EQ'd up. I usually lower from about 8K up on my EQ's but have not found a need to with this player. In fact they are so good at warm/dark/bassy sound that I've been using my JVC SZ1000 more than ever with them.

Note the iPod mini in back. LOL if you think the iPod has been touched once since I got the Walnut. Into a drawer, maybe...
Dec 8, 2016 at 11:32 AM Post #13 of 3,631
Brought my wife to an appointment, all i got with me is my V10, walnut and rx200 :grin::grin::grin: and I'm not even using the V10 for it's hifi DAC. And that's all u need to stay happy :ok_hand::ok_hand:

Seriously though i am stupidly in love with this player. I can't wait to hook it up to a power amp.

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