[DBX1]

100uF 10V solid tantalum bead cap for Vcom bypass.

The vcom reference circuit is very low current, conventional aluminum (Al) electrolytics leakage is quite high and not temperature stable.

Solid tantalum beads have very low leakage, about 10-50x lower than conventional Al Electrolytics and is stable across a wide temperature range.

This improves the low frequency common rejection of the dac, it practical term gets you lots of low and very fast bass.

What it does.
1) Substantial low end extension improvement
2) Bass slam impact increases

@b0bb and @Xoverman

My board layout is different from B0bbs which I've been following his mods. I may have a second generation LKS board compared to what you have. I am interested in adding the 100uf 10v yellow caps you added to my board and replace my blue caps with the wima red caps you have surrounded around your gold caps (see where you marked 5 in the next post - which contains a copy of the modifications you did to your board). Would this be a recommended upgrade if I have a different generation board? My caps are black caps with a brown stripe on it. I am enclosing pics of my board to compare if this helps.

Thanks much.

 

[DBX1]

Markup of some of the common mods

Initial set of modifications:
[1] XO Crystek CCHD950X Qty: 1

[2] Schottky High Barrier diodes, fully insulated low leakage, Vishay MBRF10H100 Qty:28
The actual diodes are black in the top right of the picture on the Amanero PSU

[3] Tantalum Vcom bypass Qty:2
Generic Yellow bead solid tantalum 100uF 10V eg AVX TAP107K010SRW
Unit in photo is a Wet Tantalum 150uF 10V Vishay 109D157X9010C2 (Expensive)

Followup modification set:
[4] Analog post filter.
(Check your actual DAC post filter configuration is similar to my early revision 004)
33nF 63V 5mm lead spacing 1% Kemet PHE426 metallized polypropylene Qty:4
2200pF 100V 5mm lead spacing 1% Vishay KP1830 film/foil Qty:12

[5] Wima 0.15uF 100V 5mm lead spacing metallized polypropylene Qty:14

[6] Texas Components Vishay 0.1% TX2575 2W Z-Foil resistors for I/V Qty:4
Not shown in picture, on underside of board, refer to earlier posts
https://www.head-fi.org/threads/l-k...van-dammes-double-impact.840938/post-16019754

[7] Big Mundorf 10000uF 63V. Qty:2
Replace little Mundorf LKS is using in later revisions of the LKS004.

@b0bb and @Xoverman -

Would you recommend all these mods as well for later versions of the LKS board - based on the board I have ?

Are there any changes need to be made to the mods based on the board with what I have when compared to the Gen 1 boards that B0bb did his modifications on ?

I've attached photos to show my board layout.

Unless otherwise unadvised with the board I have - my plan of attack is to modify the following, following in B0bbs footsteps:
in sections 2, 5, 7, which includes the smaller caps by section 2 - my 3 smaller caps are Nichicon Caps at 2200uF. I think the larger is 6600uF (cant verify at the moment).

B0bb replaced the Mundorf 4400uf caps with Mundorf 10000uf caps. Would it be ok to go with Nichicon 10000uf caps as a substitute or
Stick with the Mundorf recommendation?
After that, I plan to upgrade the regulators coupled to the heatsinks by the caps in section 2 based on using the replacement regulators that B0bb did with his mods. And then the crystal. I need to re-read on what B0bb and others did on the crystal and the frequency that they used with their board.

Question is should I use TCXO or OCXO for the LKS?

And then placing two 100uF 10V solid tantalum bead cap for Vcom bypass - which what B0bb did (see my post just above). As I re-read B0bbs post, this is in section 3 of his board.

These are just the "easy parts" to upgrade.

Once those upgrades are complete, I am sure there will be additional footsteps to follow for the ultimate LKS-004.

Does this sound like some worthy upgrades to start with, or ill advised with the photos I enclosed with my board ?

Thanks much.

 

[b0bb]

@DBX1
- Consider using the wet tantalums instead of the solid ones, my Gen1 did not have the large Vcom bypass, you may need to experiment to see which is better. Wet tantalums improves the low bass performance to a degree neither the solid tantalum or large electrolytic can match. Downside is high cost.

-TCXOs improve temp stability, not really relevant if you run the DAC with the case closed, stick with the Crystek CCHD 950-X. If you go the OCXO route, the existing regulators on the DAC board cannot supply enough power, you will need to build an external very low noise supply. OCXO are like the wet tantalum option above, very high performance but is expensive.

-Mundorf is an upgrade LKS made for analog regulator of Gen2 boards, Gen1 boards used something else. Nichicons are an alternative but not better. LKS used them in the previous LKS003.
I am currently using the Supertech 2T which I find to provide the bass slam without the muddyness that the other two options above brings along. Someone else previously described the large Mundorf as making the music appear "slower"
https://www.partsconnexion.com/SUPTEC-88239.html.

-The digital part of the DAC power supply, right hand cluster in your photos, upgraded using high current cap from CDE, Kemet makes equivalents.
The current draw is quite high and the replacement caps have lower loss resulting in a much cooler running cap , this leads to a longer operational life.

 

[DBX1]

@DBX1
- Consider using the wet tantalums instead of the solid ones, my Gen1 did not have the large Vcom bypass, you may need to experiment to see which is better. Wet tantalums improves the low bass performance to a degree neither the solid tantalum or large electrolytic can match. Downside is high cost.

-TCXOs improve temp stability, not really relevant if you run the DAC with the case closed, stick with the Crystek CCHD 950-X. If you go the OCXO route, the existing regulators on the DAC board cannot supply enough power, you will need to build an external very low noise supply. OCXO are like the wet tantalum option above, very high performance but is expensive.

-Mundorf is an upgrade LKS made for analog regulator of Gen2 boards, Gen1 boards used something else. Nichicons are an alternative but not better. LKS used them in the previous LKS003.
I am currently using the Supertech 2T which I find to provide the bass slam without the muddyness that the other two options above brings along. Someone else previously described the large Mundorf as making the music appear "slower"
https://www.partsconnexion.com/SUPTEC-88239.html.

-The digital part of the DAC power supply, right hand cluster in your photos, upgraded using high current cap from CDE, Kemet makes equivalents.
The current draw is quite high and the replacement caps have lower loss resulting in a much cooler running cap , this leads to a longer operational life.

B0bb -

Thanks much for the j fo. I did see that you used the wet tantalums for section 3 of your mods which you did and described as incredible Bass slam. Each wet tantalum is $50 at muser, but I will go with this upgrade after I do the first few upgrades in sections 2, 5 and 7.

Thanks much for the advice on the crystal and the caps in the digital section. I will upgrade it as per your instructions.

After those upgrades are complete, I plan to upgrade the voltage regulators as you did in the caps area. A bit expensive, but not as much as the wet tantalum caps.

After that, we'll see what other upgrades may be needed. Maybe the journey for the LKS will end with these items.

 

[DBX1]

@DBX1
- Consider using the wet tantalums instead of the solid ones, my Gen1 did not have the large Vcom bypass, you may need to experiment to see which is better. Wet tantalums improves the low bass performance to a degree neither the solid tantalum or large electrolytic can match. Downside is high cost.

-TCXOs improve temp stability, not really relevant if you run the DAC with the case closed, stick with the Crystek CCHD 950-X. If you go the OCXO route, the existing regulators on the DAC board cannot supply enough power, you will need to build an external very low noise supply. OCXO are like the wet tantalum option above, very high performance but is expensive.

-Mundorf is an upgrade LKS made for analog regulator of Gen2 boards, Gen1 boards used something else. Nichicons are an alternative but not better. LKS used them in the previous LKS003.
I am currently using the Supertech 2T which I find to provide the bass slam without the muddyness that the other two options above brings along. Someone else previously described the large Mundorf as making the music appear "slower"
https://www.partsconnexion.com/SUPTEC-88239.html.

-The digital part of the DAC power supply, right hand cluster in your photos, upgraded using high current cap from CDE, Kemet makes equivalents.
The current draw is quite high and the replacement caps have lower loss resulting in a much cooler running cap , this leads to a longer operational life.

@b0bb -

Thanks much for the info. I did see that you used the wet tantalums for section 3 of your mods which you did and described as incredible Bass slam. Each wet tantalum is $50 at mouser, but I will go with this upgrade after I do the first few upgrades in sections 2, 3, 4, 5 and 7, unless it is not recommended to do.

Do you have any advice on what caps I would use for section 5 for the caps on my board ?
You had went with a mix of polyester caps, blue caps with Vushay at 33nf, the black is a mystery to me on what caps and values you used. I could not find those values.
I see for the red caps in the remaining sections, you went with the Wimas. Do you remember what values you used for those caps?

The caps you recommended from parts connexion shows 50v values. Should I be using 63v caps or is it a limitation with the case where I should use 50v?

Thanks so much B0bb.

Thanks much for the advice on the crystal and the caps in the digital section. I will upgrade it as per your instructions.

After those upgrades are complete, I plan to upgrade the voltage regulators as you did in the caps area. A bit expensive, but not as much as the wet tantalum caps.

After that, we'll see what other upgrades may be needed. Maybe the journey for the LKS will end with these items.

 

[b0bb]

The black and blue caps are polypropylene, Mouser sells both types, the catalog picture for the black caps still shows the old blue cases.
The red Wimas are lower quality metallized polyester film used to bypass the powersupply electrolytics.

You should check your Gen2 board for the exact values, LKS may have changed them.

Each side of the analog supply is 15V, incoming DC before the regulator is 30V-35V, 50V for the filter cap is adequate.
63V is physically too big to go onto the board without modifying the case.
When in doubt measure the voltage across the terminals of your existing cap.

 

[DBX1]

@b0bb

Thanks much for your input! Hopefully these are the last questions before I get into modding my board. I have parts on the way from Mouser and will be placing an order for the caps from Parts Connexion as you suggest.

So regardless of the version of board I have compared to yours - is it still advisable to start the upgrade on my board in sections 2, 3, 5, 7

Replace the nichicon caps in the digital section with high current cme, or kemmet (I know how to replace the cap value and voltage value with something higher, but not sure what you mean by current as you suggest, will look at their product list later to see if they have a high current line as you mention)

Section 4 find out the specifications as you mentioned above (I asked jinbo about the type of cap used, voltage, and value of those caps) and replace with either polypropelyne or metal film wimas & vishay caps that you used.

If it is suggested to do this, my plan after the above set of upgrades are complete, Phase 2 of upgrades are to tackle sections 1 & 6 (underneath the board from Texas components) to match the specifications of these parts to what you done with your board.

After those items are complete, phase 3 is to go after upgrading the voltage regulators with the parts you used for your voltage regulators. Will this require a hot-air gun to fully complete these steps? I am equipped with a temperature controlled soldering iron from Weller with a Copper wick to suck out the solder at this time which I believe should do the job for the through-hole components, and isypropyl alcolhol to remove the flux residue. (Also equipped with a multi-meter and an lcr multi-meter)

But I am concerned about the components that are soldered to the board. Particularly the regulators. I am not sure if my soldering iron with wick will heat up those components reliably to remove those components without risking damage to the board. Andif I have to remove/replace smds, I read that it's best to use a heat gun instead of the traditional solder as the solder needs to get underneath to the pad for best results - as opposed to just having the solder melt to the component and the exposed pad.

Thanks for your valued input B0bb.

 

[DBX1]

People - I can't stress this enough... Remove the residue post soldering. This could form virtual solder bridges between components. I had a situation where I replaced caps and resistors in a preamp. A lot of them. This was an all-cap all-resistor rebuild on a 30+ year old preamp. All was fine with the replacement components. Except that has a headphone Jack where I was picking up an imbalance in left and right volume outputs. The values replacing components all checked out and the replacement components are in their rightful place. All solder joints looked fine. But I did not clean up after my work done in the preamp. A good couple of hours cleaning all boards I worked on with isypropyl alcohol (even on boards I did not work on) and letting it dry after a few hours removed the output imbalance of the headphone output. Problem solved. Who knows what other unknown problems I solved after that clean-up. Make sure to have lots of cleaning towels handy. You will need them when performing a cap/resistor rebuild.

 

[mrjayviper]

looking to buy this DAC for my speaker system. Does anyone know if all 8-channels of the DAC chip are in used? (8-channels x 2chips = 4-channel on a balanced output via XLR)

 

[dmkbox]

HI! Got 004 mini today. Optical input not work. Can someone take photo of the board near optical connector and connector itself? Sure it broken.

 

[ProLoL]

Irrelevant*

 

[ProLoL]

I want to cover the transformers with copper, can anyone provide a link or recommend a suitable piece to cover them?

 

[leondikim]

I have been enjoying this DAC a lot after modding most of the parts that this awesome community offers. However, 004 suddenly stopped sending any analogue signals (both RCA and XLR) to my headphone amp after I unplugged and plugged back on a power conditioner. 004 still receives the digital signal via i2s (LED status indicator shows that 004 receives the digital signal through i2s with the right sampling rate, 192 KHz). Is there anyway to start trouble shooting (or diagnose) on 004 to find out what causes not to send analogue signal to the amp anymore?

I feel comfortable enough to open up the unit and take it a part if necessary. Any suggestion or recommendation would be greatly appreciated!!

 

[ESL57]

I have been enjoying this DAC a lot after modding most of the parts that this awesome community offers. However, 004 suddenly stopped sending any analogue signals (both RCA and XLR) to my headphone amp after I unplugged and plugged back on a power conditioner. 004 still receives the digital signal via i2s (LED status indicator shows that 004 receives the digital signal through i2s with the right sampling rate, 192 KHz). Is there anyway to start trouble shooting (or diagnose) on 004 to find out what causes not to send analogue signal to the amp anymore?

I feel comfortable enough to open up the unit and take it a part if necessary. Any suggestion or recommendation would be greatly appreciated!!

In your case I would initially check if there is sound in the I/V converter resistors when you execute a test signal, for example 1khz 0db, from the result I would search backwards or forwards of this stage.
The resistors are under the pcb, here these new ones were installed above:
https://www.head-fi.org/threads/l-k...van-dammes-double-impact.840938/post-16177709
My GEN1 still works perfectly, I don't know how many users here still have this DAC ?.

 

[leondikim]

In your case I would initially check if there is sound in the I/V converter resistors when you execute a test signal, for example 1khz 0db, from the result I would search backwards or forwards of this stage.
The resistors are under the pcb, here these new ones were installed above:
https://www.head-fi.org/threads/l-k...van-dammes-double-impact.840938/post-16177709
My GEN1 still works perfectly, I don't know how many users here still have this DAC ?.

Thank you, ESL57!
Would you test the voltage on these I/V resistors while playing a test signal, 1khz 0db?