[b0bb]

The caps will fit but is such o high capacitance (and 6.1A) recommended for the low power clock?

You mentioned PSRR earlier, find out how a bigger cap changes this and you will have the answer.
At some point you have to just try and see for yourself on your DAC.

 

[dcguy73]

I can't believe this thread has 286 pages going. In retrospect, the original LKS MA-DA004 DAC (without mods) was a terrible, nails-on-a-chalkboard Delta-Sigma horror machine. When I finally sold mine and got something else, I realized how bad it was. For the price and the weight, it was incredibly disappointing. I was not willing to open it up and start soldering to "fix" the sound.

 

[b0bb]

The next step in upgrading the 004 is optimizing the 768kHz performance.
004's I/V handling 768kHz has amplitude overshoot issues.

Very troublesome at high frequencies as it can create unwanted energy spikes at the output.
This extra acoustic energy will reflect off walls, the insides of the headphone, causing unwanted interference with the next audio wavefront coming out of the DAC.

Interference will both reinforce and cancel parts of the audio spectrum, causing very uneven frequency response in the room/ headphones.

I use square waves to provide the impulse and to observe the response.

Here is the stock output.

This is correctable.
After correction, amplitude overshoot is mostly gone.

Close up of the corrected response.
This is an earlier version, the current compensation I am using has a steeper rise time.

Close up of uncorrected transient response.

 

[b0bb]

The compensation scheme plays around with the 2 caps below.

Horizontal cap controls the rising edge/overshoot.
Original used 330pF which produced the slower risetime.
Reducing it to 220pF improves the risetime but without running into overshoot.
This is close to the 200pF LKS used on the Gen2 004.

Vertical cap affects the falling edge/undershoot.
Value is 680pF

Note: Gen1 board, someone with Gen2 will need to do the same measurement to see if the comp values apply

 

[b0bb]

Another component of the 768k improvement.

Replaced the DS90LV032A LVDS receiver used on HDMI I2S input. This one is from Analog Devices ADN4666

• Better jitter performance
• Better ESD tolerance

More details here
https://www.head-fi.org/threads/singxer-su-6.902272/post-16596562

 

[Xoverman]

The next step in upgrading the 004 is optimizing the 768kHz performance.
004's I/V handling 768kHz has amplitude overshoot issues.

Very troublesome at high frequencies as it can create unwanted energy spikes at the output.
This extra acoustic energy will reflect off walls, the insides of the headphone, causing unwanted interference with the next audio wavefront coming out of the DAC.

Interference will both reinforce and cancel parts of the audio spectrum, causing very uneven frequency response in the room/ headphones.

I use square waves to provide the impulse and to observe the response.

Here is the stock output.



This is correctable.
After correction, amplitude overshoot is mostly gone.



Close up of the corrected response.
This is an earlier version, the current compensation I am using has a steeper rise time.

What makes you shur that it's not the scope prob?

 

[b0bb]

What makes you shur that it's not the scope prob?

The purpose of the exercise is to document the transient response, shame on those not setting up the probe correctly.

Since you asked, this is the rather boring picture of the scope and its probe on the calibration terminal.
This is a real hardware square wave generator, much cleaner than the DAC is ever capable of.
Probe is slightly overdamped, zero overshoot.

 

[Xoverman]

The purpose of the exercise is to document the transient response, shame on those not setting up the probe correctly.

Since you asked, this is the rather boring picture of the scope and its probe on the calibration terminal.
This is a real hardware square wave generator, much cleaner than the DAC is ever capable of.
Probe is slightly overdamped, zero overshoot.

Great job b0bb,
Are you using a 1Khz square wave file or REW? Amplitude? lks oversampling filter?
And what front end? Singxer or amanero? HQPLAYER?

 

[ESL57]

I can't believe this thread has 286 pages going. In retrospect, the original LKS MA-DA004 DAC (without mods) was a terrible, nails-on-a-chalkboard Delta-Sigma horror machine. When I finally sold mine and got something else, I realized how bad it was. For the price and the weight, it was incredibly disappointing. I was not willing to open it up and start soldering to "fix" the sound.

I can assure you with knowledge and with many comparisons of dacs in the current market, that a well-tuned LKS004, is at the level $ 3,000 to $ 4,000 dacs, another thing is that you like dacs of renowned brands and designs not "made in china", otherwise this tuning will squeeze the most that two ES9038PROs can offer. Of course, if you like the sound of two TDA1540s this dac will not be for you.

 

[dcguy73]

I can assure you with knowledge and with many comparisons of dacs in the current market, that a well-tuned LKS004, is at the level $ 3,000 to $ 4,000 dacs, another thing is that you like dacs of renowned brands and designs not "made in china", otherwise this tuning will squeeze the most that two ES9038PROs can offer. Of course, if you like the sound of two TDA1540s this dac will not be for you.

"Well-tuned" being the operative word here. The default LKS MH-DA004 DAC needs to be "tuned" and "fixed" and I'm not up for that. It had just been "tuned" to fix overheating issues by the manufacturer when I purchased it years ago. I'm certain that if you invest enough money and time into almost any modern DAC, it could sound great, but I'm not looking for fixer-uppers when shopping for DACs. If that's what you're into, that's great, but the $1.5K LKS DA004 should at least come with a warning label that it's not-quite-ready-for-prime-time at its purchase price.

I have no grudge against ESS DACs. Any DAC chip can be made to sound great or terrible depending on its implementation. I'd happily put my default dual-TDA1540 DAC against the default dual-ES9038PRO LKS DAC and see which sounds better.

As for my experience with comparing the LKS to other DACs I've owned, I bought the Holo Audio Spring KTE v1 from Kitsune HiFi before selling the LKS MH-DA004. Tim from Kitsune asked me to write a review on his website about what I told him in confidence, that in a 1-on-1 comparison, the Holo was leagues smoother and more musical-sounding than the etched and digital sound of the MH-DA004. Because I was afraid of crapping on the LKS' resale value, I never said a bad word about the LKS DAC publicly.

Now that I no longer own the LKS, I'm free to say what I like about it, and you're free to ignore my opinion.

But if you're a first-time buyer reading this thread, think twice before you go with LKS. I pity the poor n00b who spends hard-earned money on this DAC without thoroughly reading this thread and realizing what he/she is in for in terms of modding necessities. I know I was misled by it.

 

[b0bb]

Great job b0bb,
Are you using a 1Khz square wave file or REW? Amplitude? lks oversampling filter?
And what front end? Singxer or amanero? HQPLAYER?

1kHz square wave 0.95 of full scale.
768kHz sampling rate

I use Audacity to create a wav mono audio file.

004 uses the Slow linear phase filter.

Singxer SU2 used to supply the I2S feed.
Amanero max sampling rate is 384kHz

HQPlayer for the playback, linear phase filter.

 

[b0bb]

Lower sampling rates should not be used for generating the square wave, the settings I used are

• 768k sampling
• Linear phase filter for playback

This generates the lowest sampling artifacts.

 

[b0bb]

48kHz sampling, linear phase.
There is pronounced ringing.

Note ringing starts before the falling edge, this it the pre-ringing that is characteristic of linear phase.

96kHz, ringing is much reduced.

 

[b0bb]

Sampling artifacts are still present at 768kHz, amplitude is much reduced.

 

[b0bb]

48kHz minimum phase.
No pre-ringing.
Post ringing in very pronounced.

I avoid minimum phase filters due to the amplitude overshoot problems.
Soundquality wise this is responsible for an ear-bleeding experience, very bright, details are etched

48kHz linear phase has less ringing on the 004.