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 have been using these with good results.

Be careful to install these in the correct way. They have a white band on one end. This is the (+) positive end. There is also a + sign however it is very hard to see.




All the Left R6 are in parallel and all the right R6 are in parallel so I make sure I measure each one as I install them as if you create a short you would have no way to figure out which one of the 4 is shorted.

Measure using the diode setting on your meter. Plus to the TP in between the opamps (ground). negative to one side of the cap then the other side. One side will show short to ground the other will show a resistance. The resistance should be the same on all R6’s both right and left. It would be a good idea to see what this is before you start.

Also if you are changing the transformers it’s a good time to remove them before you start on the VOCM mod as it gives you more room to work.

Below are the 8 locations to install the caps.



Remember these mods are done at your own risk. I have heard of members trashing there analog board and needing to pay for a replacement $$$$


Placed the newly upgraded PS Audio DSD MKI DAC, which I sent to JK Richards to do the mods, into my system at around 6 pm yesterday evening after the system had been unplugged for two weeks and was pleasantly surprised how good the music flowing from it sounded. Normally my system remains turned on and in standby at all times, but even then, it takes at least 30 minutes to an hour of playing music before the sound really starts to gel to the point where I get lost in the music. Yesterday I was held captive immediately and remained affixed in my listening chair for 4 hours straight as I went through my music collection as if hearing these silver discs for the first time. The PS Audio MKI DAC was no slouch to start with, and I thoroughly enjoyed listening to music through it, but it’s an entirely new and more refined DAC now.


The top end is more detailed while also sounding smoother and more delicate. Cymbals have more shimmer and sparkle, and their presence lingers longer as the sound decays into a blacker background. The midrange and vocals sound absolutely stunning and to die for! Again the lower noise floor reveals subtle inflections in the vocals that were previously obscured, further suspending my disbelief.


The bass now digs deeper and is more controlled and articulate. The foundation of the music has more drive and bass lines are easy to follow now. I also noticed I don’t need to listen as loud in order to get the bass to come alive and really boogie. Before when listening at lower levels the bass never really had the presence and punch it did when turned up louder. Now even at much lower levels everything including the bass sounds prefectly balanced.


I can say without hesitation, this is the best bang for the buck upgrade I’ve ever made.





Agree with above post as it is almost exactly how I would describe the upgrade. I can attest to the massive enhancement of the DSD Mk1 after the APS transformers, VOCM mod, and I2s input shorting plug on unused input.

I had @richardselectronics do the work on the unit. Quick turnaround.

Huge soundstage, and control with detail and presence.

The Bass response is deep and defined.

If you have a DSD1, this is a no brainer. It is then an endgame DAC.

I have had a lot of separate DACs and high end source units with modded DACs from a lot of the usual vendors here in last 20 years.

All good, but this is another level totally for the price people blow on cables here.


We just finished a bunch of Vocm and transformer mods.  Hopping to make some happy listeners. 😀

(moving my review over from the other forum)

So… I am in the fortunate position to be able to compare a bone-stock MK1 vs a jkrichards modded MK1 (Transformers + VOCM). I purchased the latter from jkrichards, which he had already modified.

For the tests, both DACs were left on for 2 hours for some warm up. Both powered from a PS Audio P3 generator. RCA outputs to 2 inputs on the preamp. Both fed from an Innuos Zen3 mini via coax (which I had to swap between the DACs for testing). Before getting into listening, I used a dB meter and pink noise to mark on the preamp the volume settings as the modded DAC has a bit more gain and I didn’t want that interfering my impressions. I also decided that using the pre was better then attenuating the output on the DAC; the Preamp we make here uses a TVC so it is very consistent across the volume range.

Usually comparing components, the difference in character immediately makes certain things stand out and may throw off more objective listening and critique. It’s not the case here because the character, tonal balance is almost the same. The “house sound” is pretty similar… so if you like the PS Audio DAC sonic signature, you won’t be thrown in a different direction here.

So… the sound. It is just simply, consistently, better. The separation in the mix of instruments and voices is improved. Definitely a bit more prat. Sightly more airy without being turned up. As others have mentioned, the bass is definitely improved in terms of control and tonality (I personally find real tone in bass difficult to achieve and this mod delivers the goods) The whole sound is more refined, more controlled, without getting dry or astringent… nor did it get lush and colored in the process.

Definitely a worthy upgrade and really a no-brainer if you like your Directstream but want more of that same goodness. It’s a Directstream living its best life… as the kids say.

fuses, very expensive fuses!!!!  

couldn't resist... please carry on... :)

I forgot about the shorting plugs, was going to purchase some to be shipped back with my DAC. Can anyone comment on the improvements they bring to the DAC? 

I think you may be able to order the i2s shorting plug for the i2s input #2 which is supposedly the noisier one from Jeff, or post a WTB on the Marketplace at PSAudio and somebody should have one. I guess you can make them also if you know what you are doing.

I have one and also a USB shorting plug. I use the i2s input #1 from a Matrix USB converter which is fed by Lumin U1 mini streamer.

All I can tell you is the noise floor is lower overall with all of the mods which is always a good thing.

It is a cliche, but the music comes out of a black background and sounds live on good recordings. 

I should note I also kind of lucked out and there was a used analog power board module on the PSAudio forum I picked up and installed. Ordered a decent external Chinese LPS to use with it and that also was a nice incremental upgrade for minimal cost.

Really pleased with this DAC.


Good thing we can continue the discussion here : )


I have a long weekend ahead and hope to share some photos of the internal power supply with changes for the supply of the digital part


@Jeff: Do you know when the next batch of APS trafos is ready for shipment? Cant wait

These MK1’s are hard to beat.

We will also reconsider making another batch of power boards. Our break even number is 5 boards at $300 ea.

This is a plug and play solution that will allow you to use the internal PS or the external one. If no external PS is hooked up the unit will use the internal PS. If the external PS is hooked up then the External PS will be used. It will be automatic and also will pass the power to the analog board at the correct time during power up. This will be a card that slides in the Bridge port with the external power supply connector and LED indicator. All one needs to do is move the analog PS plug to the new board and connect the supplied cable to the analog board. Kit will include the cable with the 2 pin connectors for the external power supply and the DSD.
We make the cables out of 14AWG 2.4mm OD Silver Plated FEP Wire High Purity OFC Copper Cable.




This is what everyone will receive.


It’s very simple to install.

  1. Remove top cover and Bridge II / Cover. Use a ground wrist strap for static protection.
  2. Slide this DS DAC EXTERNAL POWER CONTROLLER board in the Bridge II slot and fix with the 2 screws.
  3. Remove the power connector from analog board and connect to the DS DAC EXTERNAL POWER CONTROLLER boards [INTERNAL PSU IN] connector.
  4. Use supplied power cable and connect from analog board power connector to the DS DAC EXTERNAL POWER CONTROLLER boards [POWER OUT TO ANALOG BOARD] connector.
    Note: all power connectors are keyed for correct polarity.
  5. Test the unit by powering on the DAC AC switch “without” the external power supply connected. The DAC should work as it did before using the internal power supply. (NO LED) Internal power supply mode.
  6. Power down the unit with the AC switch on the back of the DAC. Connect the external power supply to the DS DAC EXTERNAL POWER CONTROLLER boards external connector and turn on the power supply “only” at this time. The LED on the Power board should light RED (Standby Mode)
  7. Power on the DAC’s AC switch. The LED should turn GREEN indicating you are now powered from the External Power Supply. (Normal External Power Mode).
    *Always turn on the external power supply first or at the same time as the DAC AC power.
    You can leave external power supply on 24/7 as the DS DAC EXTERNAL POWER CONTROLLER board will sequence the external power supply to the analog board at the correct time.



@Jeff: Do you know when the next batch of APS trafos is ready for shipment? Cant wait

We have one pair available now. More to come in June.

If you do trash your analog board, it is not the end of the world. I performed the xformer mod. Difficult to remove xformer without a quality solder sucker. Although I thought it was performed properly, I had some intermittant noise. Sent to PS Audio who replaced the audio board for $300. So it was $300 plus shipping to PS Audio. I was expecting the repair it to be much more expensive. Hats off to PS Audio.

Been letting my upgraded DAC continue to break in when not listening via the USB stick on the PST. Listening this morning and the sound has continued to improve. Soundstage has expanded and image specificity has become more pinpoint and focused. Overall the music has become even more satisfying and intoxicating to listen to, leaving me grinning ear to ear. Thank you so much Jeff for making these upgrades available. Once everything settles in I'll be ordering the shorting plugs. 

Glad you are enjoying your MK1.  The USB shorting plugs makes a big improvement If you are not using that port.


Wow Jeff these power boards are elegantly designed. Thats more plug and play than I would have ever expected. 

I know this is a hard question to answer, but how "good" of an external PSU is needed to make a sonic improvement? Would a mid-level Chinese eBay linear PSU be better than what's in the unit already? Or is a top-flight linear needed to make a difference? (Obviously a better supply is a better choice but I am wondering how high/low the baseline internal PS is)

I'm curious about the heat issue.  I know having the external power supply will reduce the heat issue but how do we obtain the parts to use the external power supply?   Thanks!

I am interested in this Mod', I have only learnt of this option today, even though I have seen in the past other references to a Transformer and Fuse exchange.

Is there a Ballpark Figure that can be supplied for the purchasing of all the necessary parts required for the full Upgrade?

I am only a few years into taking a Digital Source seriously and commenced using it in conjunction with the long-term used Analogue Source. I took to digital as duck does to water, and there is no conflict between the hard media types when used in my system, each are embraced for their merits.

At present I use a PS PWT MkII > Bespoke Built Valve DAC, and have been interested in having a SS DAC as a option as well. I have been demonstrated SS DAC's up to a value of £5000ish, in systems I am familiar with and not familiar with, but have yet to discover one that has really made the idea of a Home Demo' seem worthwhile.

Maybe not of too much interest to this thread, but during some of the DAC Demo's there has been the use of different hook up methods and during the short periods of trials, I always seem to prefer the Coax Cable over others used.  

The method under discussion for Mod's does seem to produce a DAC that is competitive with high price tag models for a reasonable cost, as well as offer a further option for a DAC to be used when carrying out Streamer > DAC investigation, which is yet to take place. For this reason my attention is captured. 

Having a DirectStream MK1 that's really cool.  I'm interested in the upgrades but have been unable to locate any contact information regarding.🙄

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First pair of APS audio nickel transformers for the NEW Directstream DAC MK2.


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Sent my DS1 analog board for modification today. After re-visiting the 5000+ post thread pretty excited about this mod. Interesting to see the evolution of mods. Folks were really pleased with the results of Encore XS4400 (used in MK2) and Lundahl xformer, but designing xformer for this specific application appears to be the way to go. The Vocm mod was also universally loved by those that accomplished. Glad I came upon this and look forward to listening to the results.



Hey Jeff I thought the heat sinks with the mod installed would get hot?  Is there a way to correct this?  Or is it not something to worry about?  

There is nothing to worry about however there is 4 heat sinks, two of which are not being used or at least not very much (without the Bridge installed) and do not get hot.  By installing a heat spreading material between these heat sinks distributes the heat more evenly.  I have used M.2 heat spreading material.


Just gently spread the heat sinks slightly apart and slide the heat sink pad (for a M.2) it between the heat sinks. I held the heat sinks together with a U shaped metal spring wire I made up.


Speaking of heat sink heat, I had to replace the transformer in a Mk1 this past week. But the original is a custom unit rated 8v secondaries, 2 x 25VA and not available. I chose an off the shelf 6V rated out 2 x 25VA unit and tg it's working fine, with less heat across the linear regs too of course. It's actually delivering about 7.4V AC V out in mine. The original toroid has a band shield, and there was room in there to wrap a band shield around the new one. I went with this one: Triad- VPT12_4170


And may I ask, do we have any schematic info on the Mk2? Output section in particular? Thanks, TK

No schematics on the MK2.

Good to know you found a good replacement power transformer.

Thanks for the info.

I'm curious what properties nickel has that gives it an advantage over iron transformers? I still can't believe how much better the PS Audio DSD MKI sounds after replacing the off the shelf transformers with nickel transformers and upgrading the caps. 

Much lower distortion. The nickel is just part of the equation in making a great transparent audio transformer.  We design these specifically for the MK1 or the MK2.  They are not interchangeable.  

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It seems the other forum is moving reviews of the Vocm mod and transformers to a members only area of their forum so only members can view them now.


Here is what is being moved to the private area:





Just received and installed JK Richards’ most excellent APS nickel core audio transformers in the Mk1 DAC. Very initial impressions are extremely positive. Have listened to two very familiar Lyle Lovett cuts so more to come later today and this weekend, but I’m really liking what I hear so far.

Also, @jkrichards tip to buy some kind of proper de-soldering station is brilliant. It took me about 5 minutes to remove both Edcor XS4400 transformers and another 10 minutes to solder in the new APS units. DAC powered right up and worked the first time. Yay!


APS DAC Xformers



Update: Thanks to JK Richards for pointing out the need for the Vocm upgrade as part of the nickel transformer swap. Bought a magnifying lamp and discovered I can still handle surface mount parts without too much fuss.

Just finished this and playing some more classic Lyle Lovett. Man this DAC is getting absurdly great.




Yessir. The sound is simply magnificent. Hard to describe the combination of both ease and articulation. Back to that proper place of just enjoying loads of music. A good sign for sure.

My audiophile goal in general is to elevate both my digital and analog front ends to be equal but different. So far so great.




Just received my DAC after the Vocm and APS xformer mod. Read the reviews on this thread and expected an improvement; however, I’ve heard it before and am a tad jaded. I expected a subtle improvement. Whenever, I make a change the first things I put on is the Stereophile Vol 2 Test Cd to verify I didn’t swap channels and phase. As I listen to “The Fender Bass Guitar you are about to hear should appear to come from the left……”, I’m like OMG! The low end authority and inner detail was so obvious. The out of phase test throws an image to the front and right of the right speaker for some reason. This time it is farther forward and to the right and chiseled in granite. Wow, this is really good. A few folks mentioned more bass. I was a tad concerned as it occurred that the software may have been tweaked to make up for the original xformers and with the APG xformers it may be an issue. I thought not a biggie as I can correct. Well after only sitting with this for an hour not on board with the more bass statements. Authority, control, articulation of the low end; yes, absolutely concur, but not larger amplitude. When I get around to doing Room EQ Wizard (REW) sweeps I do not expect to see more bass. So freaking happy. To put this in perspective, IMO this was a bigger upgrade by a wide margin than when I went from Perfectwave MK2 to the DS DAC (aside from going from edge to buttery smooth) from a perspective of detail, soundstage, chiseling of instuments within soundstage, tight grip on low end. Really happy. Thanks Jeff!


last visit



Thanks. I’m happy you are enjoying your new DAC upgrade. This upgrade brings this DAC’s sound quality up to and even surpass the new MK2. Tho The MK2 transformers do make a big improvement in the sound quality for MK2 fans.

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For the people who made the VCOM mod and Richars’ transforms, what % quality increment would you assign to each mod? I ask because I’m getting the caps for the VCOM mod but I still haven’t been able to buy the transformers, I’m using the 4400.

Can't give you a break down of the percentages of each mod, as I had Jeff install both mods for me. But I would estimate the percentage of both mods combined is easily a 50% improvement, but in terms of musical involvement and enjoyment, there's a night and day difference. Every parameter of the sound has improved. Considering the cost of the upgrades, even if you pay Jeff or someone else to install the mods, is a no brainer.