DIYINHK AK4497 DAC Mods

chinook9

Member
2013-08-15 4:00 pm
I have a DIYINHK AK4497 DAC. There are a couple of relatively easy modifications that can be made.

The DIYINHK website states:
The PCB is designed to be DIY friendly.

Diyer can cut the trace and uses the socket labelled AVDD_R(5.0V) for the supply the right channel analog power supply individually.

Remove FB1 and useDVDD(3.3V) for optional individual digial power supply.


In your judgement, is it likely that these modifications will improve the sound of the DAC? Also, which trace would be cut and where?
 

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Looks like the AVDD follows the trace colored red in the pdf file below below. The green trace goes to another power connector so it would presumably need to be cut somewhere before it meets the red trace.

As to whether or not it should be separately powered, you would have to try it and see if any difference in sound quality. If you don't believe there is any benefit you could always solder the cut trace back together and use a single power supply.

That said, you should probably use a really good USB board for testing since jitter there will also affect sound quality. Also use a good amp and speakers. In other words, if any part of your system is not up to par its possible there would be an improvement from separate power, but your system might not be working good enough to make the power supply difference easy to hear.

Additional Comments:
The left/right channel analog reference voltages appear to be VREFHL and VREFHR. If interested you might take a look at how AKM powers them on the AK4497 evaluation board, which can be found at: https://www.akm.com/content/dam/doc...dac/ak4497eq/ak4497eq-en-evaluationmanual.pdf ...schematic is on page 39. Looks much like a Jung type of regulator and very similar to what is used for each L/R channel on AK4499 evaluation board. The regulators sound good for analog audio which is probably why they use them. Probably better not to use an LDO for that.

Regarding USB boards, I found JLSounds I2SoverUSB to sound like it had lower jitter than a diyinhk USB board. Both USB boards use the same clocks it looked like, but there would seem to be other implementation differences that affect performance.
 

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chinook9

Member
2013-08-15 4:00 pm
Thank you Mark! That's more than i hoped for.

I had checked out the JLSounds board. I imagine I could figure out how to install it, however, I'm not sure about the need for drivers (if any) when playing from Android.

I've pretty much moved over playing FLAC files or streaming the best quality from TIDAL. I do not use any DSD.
 
Recommendation for the JLSounds USB board seconded; they work really well and are excellent value for money.

I use my Samsung Android phone to hook up to a JLSounds USB board. You just need a USB OTG interface cable and it just works.

If you've not come across it I recommend looking at the 'USB Audio Player Pro' app for your Android device - it is a superb music playing app optimised for Android platforms, bypassing the less optimal standard Android playback constraints. Using it on my phone I am able to 'play' hi-res FLAC files either locally on my phone or, better still, out to the JLSounds board to be decoded by a decent DAC - far superior to MP3 listening.

USB Audio Player PRO
 

chinook9

Member
2013-08-15 4:00 pm
Thank you for the recommendation nautibuoy. I wasn't aware of the changes that have been made to UAPP.

I will be heading to my winter residence (AZ) this weekend and will try it as soon as I'm unpacked. I expect I'll also order a JLSounds I2SoverUSB. I may also mod the DIYINHK DAC as described by MarkW4 if I feel comfident I won't mess up cutting the trace.
 

lasercut

Member
Paid Member
2017-12-19 4:35 pm
If interested you might take a look at how AKM powers them on the AK4497 evaluation board, which can be found at: https://www.akm.com/content/dam/doc...dac/ak4497eq/ak4497eq-en-evaluationmanual.pdf

That evaluation board datasheet actually looks like it delves into the how-to of programming the chips unlike the actual DAC chip datasheets, first time ive seen that. The Ak4499 doesnt have anything like that (yet)... I thought full training in digital programming was just expected for anyone using the chips.
 

lasercut

Member
Paid Member
2017-12-19 4:35 pm
Not really a mod but If you are using headphones you could try enabling HLOAD pin (rated to drive loads down to 120ohm) and driving headphones directly from DAC chip outputs ... was always curious what that might sound like.

Also try playing around with filter modes. AKM's super slow filter is supposed to be like NOS , DIYinHK actually posted measurements here showing perfect square wave output from Ak4497 with this filter.
My favourite was the slow roll-off filter, the default short delay sharp rolloff sounded pretty poor.

See in page 61 in the datasheet for configurations of the filter pins (SD,SLOW and SSLOW),
DIYinHK has provided jumper pads for all the pins which are labeled on the underside on the board.
 
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Thank you for the recommendation nautibuoy. I wasn't aware of the changes that have been made to UAPP.

I will be heading to my winter residence (AZ) this weekend and will try it as soon as I'm unpacked. I expect I'll also order a JLSounds I2SoverUSB. I may also mod the DIYINHK DAC as described by MarkW4 if I feel comfident I won't mess up cutting the trace.

Do you have a scrap PWB to practice on? Every PWB will be a little different, some harder and some easier, but still its worth trying on something you don't care about first.
I use a very sharp exacto knife, and ohm it out. Sometimes it looks cut but really isn't.
 

chinook9

Member
2013-08-15 4:00 pm
Not really a mod but If you are using headphones you could try enabling HLOAD pin (rated to drive loads down to 120ohm) and driving headphones directly from DAC chip outputs ... was always curious what that might sound like.

Also try playing around with filter modes. AKM's super slow filter is supposed to be like NOS , DIYinHK actually posted measurements here showing perfect square wave output from Ak4497 with this filter.
My favourite was the slow roll-off filter, the default short delay sharp rolloff sounded pretty poor.

See in page 61 in the datasheet for configurations of the filter pins (SD,SLOW and SSLOW),
DIYinHK has provided jumper pads for all the pins which are labeled on the underside on the board.

Just getting back to this after settling into the AZ house.

I feel pretty comfortable cutting the trace, but before I do that, I'd like to try and change the filters.

I can see how the SD, SLOW, and SSLOW are marked on the underside of the PCB. I assume I can use jumpers to change the filter but its not clear how.

Could anyone please help me with this?
 

lasercut

Member
Paid Member
2017-12-19 4:35 pm
From the photo in the OP: for each pin there is 3 pads, the centre pad is the pin itself, you either connect it to the right H (High) pad for 1 or left L (Low) pad for 0.
You just need to make connection, jumper are convenient to change them on the fly but you can just a piece of wire.

make sense?
 

chinook9

Member
2013-08-15 4:00 pm
From the photo in the OP: for each pin there is 3 pads, the centre pad is the pin itself, you either connect it to the right H (High) pad for 1 or left L (Low) pad for 0.
You just need to make connection, jumper are convenient to change them on the fly but you can just a piece of wire.

make sense?

Great! That's as easy as I hoped it would be. I expect I'll use jumpers as I have quite a few of them.
 
Great! That's as easy as I hoped it would be. I expect I'll use jumpers as I have quite a few of them.
SSLOW/WCK must be cut, is connected to low by default.
If you want to use super slow roll off filter and low dispertion filter... you must cut that trace..

I have the same board and the board have by default hload - heavy mode enabled.

I also have the jlsounds and sounds great.. much better than diynhk one 768k isolated that i already had...and sold..
 
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Thank you Pistollero. Easy to see the SSLOW/WCK trace that must be cut. I will do that quite soon .

Have not ordered the JLSounds yet. Hate to wait for the thing to arrive from France. I may check out the Amanero which I can probably get much more quickly.

Why would you compromise just because something takes a few days longer to arrive - whatever you build will be in use for longer than those few days - and if you had ordered it when it was recommended you would have it in your hands by now! IMO the JLSounds board is better than the Amanero because it includes isolation and reclocking and sounds great. BTW, IIRC JLSounds come from Bulgaria, certainly not France.
 
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chinook9

Member
2013-08-15 4:00 pm
Why would you compromise just because something takes a few days longer to arrive - whatever you build will be in use for longer than those few days - and if you had ordered it when it was recommended you would have it in your hands by now! IMO the JLSounds board is better than the Amanero because it includes isolation and reclocking and sounds great. BTW, IIRC JLSounds come from Bulgaria, certainly not France.

Thank you nautibouy. I did just a bit of research and Amanero was not looking good. Not sure why I thought JLSounds was in France.