Modding the DirectStream DAC MKI

Gradually collecting a complete set of MkI mods… I just installed one of jkrichards external PSU switching boards and am feeding it with a relatively inexpensive LPS from AliExpress. I bought this board 2nd hard from another forum member before JK posted that he doesn’t think it makes any difference after the Vocm and transformer mods.

Could be my old friend Placebo whispering in my ear but I gotta say I’m enjoying what I’m hearing, and I actually think I’m hearing more of what I want and less of what fatigues and annoys me. Richer tones, more solid images, greater sense of space and presence. More slam and PRAT.

Maybe it all adds up :slight_smile:

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just what we need…comparing against Placebo or A-B blind testing

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The neat thing about this board is that you can disconnect or switch off the external PSU and it’ll revert to using the built-in one – albeit with a less direct path. I intend to do some non-blind comparisons when I get around to it.


after all mods were done in the next weeks I will compare JK’s APS transformers with Lundahl’s which I enjoyed during last year. it will be an interesting battle.


Please include which cap values you use with the Lundahl‘s, as this will make quite a difference.


I’d say this will sound quite recessed/less open on top end compared to the APS.

I assume 6800 will sound a more open than the APS, 8200 will sound maybe just a tiny bit less open, but 10.000 definitely recessed. 7800 would probably be equal (if it was available).

it depends, we tested 6800 and preferred 10k

I agree 6800 is too low, just also give 8200 a try, would be interesting what you think compared to 10000.

also, I need to mention that I’m using AD1839, not 32.

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Ok, I see…not sure if this can make a difference to the very top end but maybe. But I think our findings are very close.

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Make sure you remove them C704 caps when installing the Nickel transformers. They will mess up the sound.

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sure! thanks for the reminder!

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The APS transformers sound many times better than the LL1984 transformers as long as they’re no C704 installed. We spent many hours developing them specifically for the DS. It turns out the core in the LL1984 is too small for our DS. Tho the LL1984 do sound better than the Edcor XS4400.

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Yes I believe so, it would just be interesting in what range top end extension lies compared to the different results of C704 with the Lundahl and if there are general tonality differences (bass or other) for other Lüsters.

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The C704 just fixes the ringing that the LL1948 has in this application. Unfortunately it also causes severe phase errors.

Yes that’s clear. The interesting point when comparing with an original Mk II or an original Mk I (unfortunately I can’t compare with a Nickel transformer) is, that those errors don’t seem to play a negative role compared to other improvements for whatever reason.

The APS transformers are installed and I am waiting 200 hours of burn-in before critical listening.


Them old DAC’s are nothing like the DS. One cannot know what the phase error sounds like until you hear it without this error. Everything becomes more coherent and tighter when the phase error is very low.

i have probably experienced this phase thing by exchanging speaker cables (still on unmodded MK1 by that time) and fully agree it is something one realise for the first time only after direct comparison.

It is not easy to describe in usual terms, but as @jkrichards said , things get more coherent , something like the sound across the whole spectrum arrive at the same time to the ear (that was exactly my feeling when it happened before I started realising what is happening).

It may be too soon for me, but @jkrichards is this phase coherence something one can expect from the MKII upgrade transformers? Although it might be too soon for me (3 weeks with MKII) I am genuinely getting interested :slight_smile: