Modding the PS Audio Directstream DAC MK1 and MK2

I would like to continue discussing all the mods we have created for these two DAC's as it seems PS Audio is no longer allowing discussions about them on their forum.

For reference here is a link to the closed discussion.


I overlooked the reason some didn't think Snowmass 3.05 sounded better than other versions.

We revisited this with the original Rev.1 transformers and the difference between the firmware is very close. We feel Windom or Sunlight do sound very good however with the new Signature Series MK1 DAC Snowmass definitely outshines the others.

Signature Series

Just wanted to post my limited experience with the APS transformers in the MKII. I’ve only had them playing 48 hours or so. I don’t know Jeff other than dealing with him through the purchase and install of the transformers, but what he and his son have created are a revelation. I have only dreamed of sound this good. The reference tracks I use have never sounded anything like this, even in more expensive systems. the purity of sound, the intimacy of vocals, the realism, staging and separation are abundant in spades. My system, being beryllium for mids and tweeters, along with an electrostatic super tweeter, can be brutal, letting you hear every shortcoming with sources. The APS transformer upgrade, in my system I think is bigger than an amp or preamp upgrade. As can be seen from the response curves Jeff posted, yes the treble is more extended and crystalline than the stock Edcore units. Buzzy brass from the Athena Rachmaninoff Symphonic dances sounded much more like real horns and less buzzy mess. I could hear much more of Bill Evans hands doing different things and get a much better sense of the piano’s soundboard in general. Right now I’m not using a preamp, so I’m only playing my DSMKII between 40 and 70, so when I finally put a preamp back in the system, I may hear even more goodness. I’m not running Massive firmware yet, as I didn’t want to change too many variable at once, but it will be interesting to hear if I like Massive more than Antero. I do hope Jeff decides to offer the MKII transformers again some day, as I’m trying to convince a friend with a MKII he needs to do this upgrade.

How much of an improvement are the new signature series MKI transformers, and is a trade in possible?

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Thanks for your honest review of your MK2 upgrade.  Enjoy!


The signature series is not just the Rev2 transformers it's a complete system.  As these DAC's get better and better sounding, the improvements get narrower however it is an improvement.  We are continually seeking ways to improve these DAC's

One way to improve them even further is to use a DDC like the Hermes or a Matrix to feed the i2s signal.  The USB interface in the Mk1 is one of the weakest parts of this DAC.