Modding the DirectStream DAC MKI

JK, what is this pad (do you have a link)? Is the blue stuff deviating/transmitting heat? It rather looks like annisolator or n stead of putting a copper plate inbetween?

Thanks Jeff. I’ve thus far used the Hakko only for SMD desoldering.

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Just thought I would share some pictures of a mod I did to my DAC and a firiend of mine. Useing some copper sheet and aluminum tape I decide to craft an enclosure for the analog board to provide some shielding as best I could from other circuits within the DAC. The result was surprisingly good. Before I did my friends DAC we compared both DACs. Both DACS had the same modifications, APS transformers and VOCM mod. The only difference is the enclosure for the anlog board in my DAC. Without hesitation my friend said I needed to modify his. We both agreed there was no way we could live without the mod. I encourage someone who is capable of doing this to give it a try. I think you will come to the same conclusion we did and I hope you share with us your results. In one of the pictures I show the copper before it was completly sandwiched with aluminum tape.


Thanks for sharing this. Can you elaborate on what materials you used to craft this enclosure? Also describe what was the sonic improvement you heard? I have the APS/VOCM mod on my MK1. It’s been a fantastic upgrade, but if there is any gain left on the table, I’d love to give this a go.

What’s the blue sheet between the heatsinks? Is it isolation or heat conductive?

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I don’t want to lead the conversation, I’m hoping someone else will try it and comment. I could say more, but I will start with clarity, detail and sound stage presentation. The system just seems to project the music with such ease. It’s just so comfortable to listen with all the dynamics one could want. I’m really happy with what I’m experiencing. Again, the materials used are copper sheet and aluminum tape.

Heat conductive. It’s from Jkrichard.

Thanks! As JK is no forum member anymore…do you or someone else have a link where to get this stuff? Such heat conductive soft material is new to me.

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A few years ago I searched for transistor thermal pads and found a similar material. It worked great. Search Digikey for thermal pad.

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As posted here:

His email is

Web page is

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So you probably also know about the “brick d*ck” in Ypsi, then? :grin:

Material is m.2 Thermal pad,70x20x1mm for M.2 2280 SSD NVMe Heatsinks. $6 on Amazon. Pardon the late response, but addressed for future reference.

Also have the APS xformer and Vocm mods, so happy.


i ordered 2 Edcor 4400 Transformers and now is see there are already Edcor 4300
installed. As i bought the dac second hand i am a little bit confused. In other Pictures i
have seen Edcor 1412 Transformers as Standard. Can anyone light me up?
Goggle is no help, for Edcor 1412 oder 4300.


Remove and get the Richard’s power supply mod. Then his APS transformers. I think there is another mod that’s easy too while open. That will get you super close to the MKII especially with the I2S input.

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VOCM Mod made the power supply mod obsolete. According to Richard, the LPS makes no discernible difference once you do the APS and VOCM mod. I can concur. My APS+VOCM sounds much better than the EDCOR+LPS mod.


I would say the VOCM and APS or Lundahl transformer mod had much higher impact than the ext. PSU, but when you check the difference between internal and external PSU afterwards, you still hear a clear improvement anyway, maybe depending on the system‘s resolution.



@tedsmith in case you still post here some time:

I found out that in Jriver, DSD256, played with Bitsreaming unchecked in DLNA settings, sounds worse than the same track as DSD128, played with Bitstreaming checked. Also all PCM sounds even more worse when played with Bitstreamimg unchecked although there’s no real reason as this setting just affects DSD transmitted direct instead of DOP.

This could be due to some difference in the JRiver code or some difference of the DAC playing DOP vs. DSD direct (whysoever this should have an effect on PCM, too).

I expect it has something to do with Jriver code and processing, I just also wanted to mention it here in case you see some difference SQ of the DS processing DOP and DSD direct.

I have the same experience. With APS transformers and Vocm mod, I still hear the difference: with vs without additional power supply for the analog board. And I can hear the difference between power supplies, too. A good power supply cleans, opens up, and deepens the sound stage, while a mediocre (cheap ones) doesn’t make a difference.


Anton, and @jazznut , do you know what size capacitors you’ve got for the Vocm mod?

I went with 47uF as per Ted’s original suggestion and I also still hear a slight but impactful improvement when using the external PSU. JKRichards uses 220uF for his mods and claims the external PSU makes no difference when Vocm and transformer mods are done. I’m curious about whether my smaller capacitor leaves room for the PSU to still play a role – he claims not but hasn’t offered any reasoning, so I’m still looking for data and ideas.