Modding the PS Audio Directstream DAC MK1 and MK2

We are back doing MK2 upgrades.

Includes Our match R2 Nickel transformers and a pure copper IEC inlet wired with 10% Silver plated OFC Teflon jacket wire along with correcting any flaws we find.  With the new Blue Sky firmware this thing is sounding smooth and sweet.

@richardselectronics greetings!

Do you still provide/offer mods for the PS Audio Directstream DAC MK1?

If so how much does that cost/are there different options?

They are selling the PS Audio Directstream DAC MK1 for $1,800 refurbished so with that and mods, unless I am missing something, it sounds like a great price/performance deal.

We have received a lot of interest in making the bridge 2 card sound good in these MK1 DAC's.  We have been working on it for a few weeks now and have it almost completed.

One of the biggest problem with these Bridge cards is the fact that they draw a lot of current and it uses only one stock regulator.  This is why units with the Bridge card installed, the power supply heatsinks over heat and literally burns the rubber coating on the transformer wires and discolors the heatsinks. The underside of the lid gets stained and smells like burnt rubber where the wires leave the residue from the heat.  Not good.  We discovered this is one reason the Bridge 2 cards do not sound that good.

You will need at least the Signature Series PLUS upgrade.  You will have to send your unit in to have larger hestsinks installed and an additional discrete 5v regulator, a new post regulator capacitor installed along with your Bridge 2 card.

Running it through test currently.

Cost is will be announced later.  The first few will get a large discount.

 

Thanks for your review of our entry level modified DAC.  It is truly amazing what can be done with these MK1 Directstream DAC's.  Every step of our upgrade process shows great improvements.  Our top of the line Limited Edition Signature Series PLUS is just plain crazy over the top in sound quality.  Very realistic and dynamic. Simply amazing.  We have yet to find a DAC that can compete with it at any price point up to $20k.

I use the Directstream mk1 in my headphone rig, so everything in this review applies to the APS “Level 1 upgrade” mk1, as it sounds when connected to my various headphone amps. Your experience using power amps and speakers might differ slightly, but the fundamentals should sound the same. 

 

About 3 months ago I finally got fed up with the harsh “digital glare” that all my newer delta sigma DACs seem to impart onto my favorite 1990s recordings. Even the latest ESS 9038 Pro flagship chip makes just about any 16bit/44.1 recording (from before 2010) sound thin, brittle, and abrasive. The latest Burr Brown chip is a little smoother on these 16bit tracks, but on 24bit tracks it sounds grainy and low-res compared to the latest ESS chips. 

 

I first tried going the tube amp route to help “warm up” these old 16/44.1 recordings. Unfortunately, all that did was accentuate the glare and add even more high frequency noise, even with expensive 1960s Amperex and RCA tubes. 

 

The only DAC I had which DID help strip away this digital glare was the original Chord Mojo. Unfortunately though, the Mojo has a lot of other shortcomings (e.g. resolution and soundstage) that disqualify it as an “end game” desktop DAC. Nevertheless, the old Mojo helped me realize that an FPGA approach is likely the superior DAC design path when it comes to playing back these older 16-bit recordings. 

 

The only problem? There was no way I could afford to drop $8k on even a USED Chord TT2+Mscaler (not to mention a DAVE).

 

So my search for a more affordable FPGA DAC eventually led me to the PS Audio Directstream mk1, which seemed like a really cool approach (i.e. switchable firmware “flavors”). I was delighted to find a certified used mk1 for $1500 online from The Music Room, so i went ahead and pulled the trigger. 

 

I won't say I was completely disappointed when I first plugged in the stock Directstream mk1, but I was definitely underwhelmed. My first impression, as a headphone listener, was just how intrusive the noise floor on a stock mk1 is. It's significantly noisier (on both low and high output gain) than pretty much any delta sigma DAC from the last 5 years, even cheap $300 DAC/amp portables. 

 

As far as secondary complaints about the stock DS mk1, there just wasn't much there in terms of dynamics, punch, or heft. Both balanced and unbalanced connections to my headphone amps were equally underwhelming in this respect. 

 

Despite all this, the one big thing my stock mk1 DID have going for it was in the resolution and timbre department, especially when running the latest Sunlight firmware. Even on a stock mk1, Sunlight serves up an impressive degree of smooth resolution that's miles ahead of what the original Chord Mojo is capable of. 

 

In fact, I'd put the DS mk1's FPGA in the same league as today's best ESS chip when it comes to pure resolution capability (a high compliment for a 12-year-old FPGA chip). The biggest strength of the stock DS mk1 is it sounds more naturally “syrup-y” and less thin/airy than ESS chips, despite its other aforementioned drawbacks.

 

This is where APS enters into the value equation. Thanks to the custom Rev2 Transformers+VOCM offering from Jeff and his son, I'm here to say that buying a PS Audio Directstream mk1 in 2025 is still totally relevant (and an exceptional value when compared to higher-end Chord gear).

 

After only a few weeks of owning a stock DS mk1, I decided the roughly $1250 “Level 1” upgrade from APS (Transformers+VOCM) was a must if I was ever gonna be satisfied keeping this DAC as the heart of my desktop headphone rig. Accordingly, I paid the $75 to ship my unit off to Jeff in Baltimore and kept my fingers crossed that this leap of faith would work out for the better. 

 

I'm pleased to report that it did, and Jeff turned my upgraded mk1 around in just 2-3 days time. I let the new mods burn in for 24-48 hours, then put my favorite analytical headphones on and sat down to give the modded mk1 a good listen through a neutral amp. 

 

The difference (with the rev2 nickel transformers and VOCM mod) was immediately noticeable over the stock mk1. Right off the bat I sensed a less intrusive noise floor, and therefore increased dynamic range, when compared to the stock mk1. Don't get me wrong, there's still a noticeable noise floor when I really crank up the volume on my otherwise whisper-quiet THX headphone amp (at least there still is with the $1250 Level 1 package), but that noise floor is significantly improved after the mods. 

 

The second thing i noticed was just how much more punchy and sure of itself the upgraded mk1 sounds compared to stock, all without ever sounding more compressed as a tradeoff. To the contrary, it actually sounds more open and dynamic after the APS mods. Harmonics now sound livelier and instruments richer, yet there's no added brightness or listening fatigue. There's also no added bass boost or anything like that, but the low end is definitely more solid while still sounding cleaner than before. 

 

Overall, the sound of the APS Level 1 upgraded mk1 is just more realistic and effortless than the stock mk1. It still sounds like the same great FPGA at the heart of the unit (because it is), but there's the sense when listening now that a veil has been lifted at its output stage, letting that near perfect resolution of the Sunlight firmware really shine through.

 

So if you're on the fence as to whether this type of $2900 “all in” approach is still worth it in 2025 (for what's essentially a 12-year-old FPGA DAC), I would say just look at the alternative. I've honestly never had the luxury to hear a Chord TT2 + Mscaler, but i would wager that the APS modded DS mk1 (even at just the basic Level 1 upgrade package) is in the same ballpark soundwise, and at a small fraction the price of higher-end Chord FPGA gear. 

 

For those who are curious, here's how I would describe the main difference in sound between the latest ESS flagship 9038 Pro chip and the Directstream mk1 (since I own both now and have done extensive A/B comparisons). With the ESS chip you will always hear the “air” around the notes of the instruments, whereas the Directstream seems to intentionally STRIP AWAY much of that air (without going TOO far or erasing the intended soundstage). All the impressive detail of the ESS is also present in the Directstream, but flipping back and forth between the two makes everything from the ESS sound a bit more like it was recorded inside a warehouse (in terms of added reverb). You don't really even notice this added air/glare until it's been stripped away by the FPGA inside the Directstream, but the result is a more pure sound of the instruments THEMSELVES, rather than hearing the room AROUND those instruments…if that makes sense. This is true for both the stock and modded versions of the mk1. The modded version just does it better.

 

Don't get me wrong. The ESS 9038 Pro chip is extremely detailed and spacious sounding, and it sounds amazingly good when playing back anything that was either A) recorded in the last 5-10 years, or B) re-issued in 24/96 or above. But where the ESS chips always seem to falter is with older recordings and 16/44.1 files like what you'd rip from your old CDs. In those situations there's a horrible “digital glare” and harsh treble edge from any ESS chip, and it makes your favorite recordings from the 1990s and early 2000s sound far worse than you remember them sounding back then. I do realize there's a nostalgia factor at play here too, but even still, this glare unmistakably exists.

 

NOTE: I ended up buying a Matrix X-Spdif 3 ($400 used from Apos) in order to feed the Directstream with isolated I2S signal, as opposed to noisy USB directly from my phone (running Qobuz). I also got a Chinese LPS off of AliExpress in order to better power the Matrix. There's no doubt a good LPS makes a difference here and i strongly recommend getting one if you go the DDC route. I even tried the $115 iPower X-Power power supply as a comparison, but the bigger/traditional LPS from AliExpress sounded even better, and it was actually a little cheaper too ($87).

 

One final thing: APS sells $99 “digital noise eliminator” shorting plugs to plug into the unused USB and 2nd I2S port. I'm not gonna outright say these are snake oil (because I've read threads here where several users report the benefits of shorting plugs on the mk1), but i WILL say that in my particular headphone setup I don't hear ANY difference at all with these plugs in or out. 

 

This little gripe aside, the custom APS rev2 80% nickel transformers really are THE BOMB and worth every penny. I mean, where else are you gonna find a transformer that's specifically designed for a PARTICULAR model of a particular piece of gear? Not to mention finding a service tech who has worked on literally DOZENS of Directstreams and can quickly identify any other quirks your old mk1 might have going on with it. 

Here is the layout of components of our Limited Edition Signature Series PLUS units.

Just a heads up.  We only have one complete unit available now and are down to a few transformers.  We won't be making any more till next year.

Starting this Friday (11/15) we are giving customers 10% off  site wide until the end of November while supplies last.  This sale excludes VIP pricing upgrades.

The opamps in this Directstream DAC are special high frequency video opamps. The ones Danny is speaking of from Sparkos is a replacement for standard opamps (not compatible at all with the DS). We make our own discrete opamps for other equipment.

We have tested other compatible opamps however the ones in the DS work the best especially when the DC offset is fixed. We have spent 1.000’s of hours working with the Directstream MK1 DAC and feel it’s at it’s best with the Limited Edition upgrade. We even tried using a custom opamp output stage instead of our transformers and it didn’t sound even close to what have now. Ted designed these DS DAC’s to use an audio transformer for a reason.

https://www.youtube.com/watch?v=iFmOhR0zp2Q&t=1

 

Is there an OP amp in the DSD DAC? If so this OP amp Danny is talking about sounds like it would be worth upgrading to.

We have some exciting news. We have been working on a new Directstream DAC upgrade for the past six months and have finally released it.

Our new Limited Edition Signature Series PLUS DAC.

The Limited Edition is the latest model in a series of the finest and most successful DAC upgrades ever made. Providing even more presence, weight and definition than that of its predecessor, the Signature Series PLUS.

The Limited Edition clearly redefines the state of the art at a price that is not inexpensive but represents extraordinary value.

While differences in recordings are immediately apparent, the Limited Edition connects you to the intent of the musicians and the soul of the performance, drawing you in even more.

This unit extracts the room ambience like no other. You can clearly hear the room where the original recording was produced.

Only by hearing it for yourself will you fully appreciate the sonic advancements unveiled by the Limited Edition.

The Limited Edition possesses great bandwidth and resolving power combined with a purity and naturalness that is uncanny – grain and electronic artifacts are simply absent. Bass impact, depth and control is startling, while music ebbs and flows with a dynamic life that is rarely experienced outside the concert hall.

 

This upgrade includes the following upgrades in addition to our Signature Series PLUS upgrade:

1- Our New pure copper IEC AC input socket.

2- Silver AC input wiring.

3- A 50% larger pre-regulator capacitor.

4- Our discrete 5 Volt regulator for the digital input board.

5- Additional post regulator capacitor.

6- Hand-picked Rev.2 transformers.

 

Our new pure copper IEC AC input connector.

New capacitors we use.

Our new 5v discrete regulator for the digital input board.

 

Quote:

No.  We made the R2 to correct the DC offset issue the MK1's have.

Hi Jeff. Is there a version of this Rev2 transformer for the DS MkII as well?

We have been asked many times, When did we change over to the new Rev.2 transformers?

Any transformer purchase before December 20/2023 are the older original transformers.

We finalized the new Rev2 transformers on that date. These new R2 transformers allow us to do the needed DC offset tune to increase dynamics and lower the low frequency distortion in our Signature Series DAC's.

Just a heads up...
We are only able to do 1 or 2 Signature Series PLUS upgrades per week so first come first serve or until we sell out of parts.

 

We have received many inquires about making the MK1 upgrade even better however some feel that we left them out with the older upgrade.

APS has decided to give our past customers a big discount on the Signature Series PLUS upgrade.

Anyone who purchased our install of the original transformers and Vocm mod in the past 6 months can take advantage of this special.

$1499 TOTAL for our VIP Customers Signature Series PLUS upgrade. You must pay for return shipping as always.

Offer good till the end of July.

Just leave a note in the comments field on checkout. "VIP Customer"

 

I want to clear up some info on the Signature Series PLUS DAC.

We have received many inquiries about how much it would cost to upgrade a standard Vocm mod / APS R1 transformer DAC.

The standard Vocm mod we did from the beginning and is still available for a lesser cost is much different from the Signature Series. This is one reason the Signature Series sound so much better along with the new R2 APS nickel transformers. The other important thing that separates the standard upgrade to the Signature Series is the fact that we replace all the 1% thick film resistors with very high quality 0.01% thin film resistors and tune the DC offset, another major improvement in sound quality. To top everything off we install our very high quality very low impedance analog power supply for the analog board which we also isolate and filter from the stock power transformer. The unit now has two active fuses, both analog and digital. We also beef up the original power supply which supplies the 5v for the digital input board and go over the whole unit making it better than new and offer a full 1-year warranty.

This is quite a different and much better upgrade and why it cost a bit more however worth every penny when you sit down to enjoy listening to your favorite music.

 

Use a Triad VPT12-4170..  Should also add a flux band shield.

 

https://www.mouser.com/ProductDetail/Triad-Magnetics/VPT12-4170?qs=wkKrz7WmEgPxHMYAWLcN5A%3D%3D

OR

https://www.digikey.com/en/products/detail/triad-magnetics/VPT12-4170/2090067

 

 

Here is the schematic.

 

Hello friends, I suffered seriously with the floods here in the south of Brazil, my system was devastated and so was my DS MKI, as a result the transformer fried, I would like to know what the voltages are at its output, on each of the wires (blue, brown , green and red) so my technician can test that no steps forward are affected.
 

Thank you in advance!

 

 

Yes With the Signature Series PLUS it is now much easier to hear the difference. We feel it sounds much better and more focused. We install Snowmass V1 on all our Signature Series DAC’s. We feel it is a much better match with our upgrades.

You would still rank the Signature Series Plus higher than the MK2s with these new transformers?  Still prefer the Snowmass FW for MK1?  Thanks

Discovered last week that PS Audio has revised both boards in the MK2.

The analog board now has grounding tabs like the digital board. Also they neglected to remove the powder coating from them contact areas on the chassis making them grounding tabs they added useless. They also are now switching the neutral power along with the hot power via the rear power switch. (DPDT switch). On the digital board they repaired one of the patches they did on the original and added a second IC option (set of pads) instead of using them adapter boards like they did in the past. Not sure I like the idea of having open pads on the digital board as it can act like an antenna and susceptible to noise.

 

 

 

 

 

We also would like to inform MK2 owners that we will resume MK2 Transformers and mods however we will no longer ship transformers. The MK2 will only be upgraded in house.

MK2 upgrade

My scope showing how clean the stock power supply is. The old FFT posted above is using the USB input. That is what causing the noise shown (ground loop). Not the power supply. Also there are at least two discrete filter / regulators circuits after the main power supply with the 317 regulator.

FYI. Noise is not the issue and not what makes this internal supply sound so good in the Signature Series PLUS.

Yes. These are very new. More to come later as more are used.

A panel of listeners here all agreed that the new Signature Series PLUS tops all the DAC’s we have here in a blind A/B comparison.

DAC’s we have here. 1- MK1 Signature Series, 1-Mk1 Signature Series PLUS, 1- MK2 with our transformers, dCS BARTÓK APEX, ADI-2 Pro FS R, and a Holo Audio MAY KTE.  On loan a Danifrips Terminator Plus.

The biggest difference in sound quality is a taller sound stage with more dynamics and micro details. Very focused compared to the new MK2. The MK2 is also more congested.

Anyone in the Baltimore / Washington DC area are welcome to come visit us here in our studio to have a listen. Just leave us a message.

Are there any reviews from someone who upgraded their DSD MkI DAC from the original APS transformers and VOCM  mods to the new Signature series plus?

Ignorance is bliss.

Re-posting someone else old data. This is from years ago with a stock unit.

Guess you will never know what you are missing.

I might know the same about shortcomings of the stock power supply or maybe even more than you. Imagine that! But we won’t find out because I won’t share with you, so you can’t sell a $10 mod for $1000 (just a random number as an example).

.

You measured and found it not noisy. LOL Tell it Amirm (audiosciencereview.com) who measured DirectStream DAC a long time ago.

.

Come on, man, the stock power supply uses a SINGLE ML317 in simplistic configuration to feed the whole input board plus display and processor board (one cheap integrated circuit serves them all). And this is the foundation of your statement DAC? LOL

.

I didn’t overlook anything. Because I rebuild the whole power supply ground up. Only the toroidal transformer and heat sinks remain from the stock power supply.

.

Your original APS transformers with my complicated Vocm mod really showcase the difference with the additional power supply vs. without it. I don’t know, but it could be your simple / cheap Vocm mod that didn’t allow you to hear the difference in your modified DAC.

 

PS

Yes, I did the same withTurboTK. I told him that he is wasting his really brilliant ideas when he uses this stock power supply as is.

Anton, Antony_s0s Please get your facts straight.

We don’t just do a simple Vocm mod like the weird “sandwich conglomeration you did. Who would even consider buying anything done that way? What a mess. We professionally change and add many other components and adjust the DC offset for our new R2 APS audio transformers. This lowers the low frequency distortion even more. I believe you purchased our old nickel transformers which show little difference if any at all with different power supplies. Things have changed a lot since we started using these new improved R2 audio transformers. What a difference they make. No one has ever used the power supply we are using including us until recently. We have tried many designs with very little improvements if any until we used these APS modified supplies together with our NEW R2 audio transformers and mods. Most internal supplies that others have performed in the past looks like a hack job at best that no one would want to pay good money for. Ours are done correctly and professionally. We warranty our DAC’s for a full year.

Unlike you, we have measured the stock power supply and found it is NOT noisy. There are another issues we discovered and corrected that you don’t know about. Imagine that😊. And no, schottky diodes are not the correct thing to do as you did. That creates other issues you are overlooking.

Our Signature Series PLUS is already a statement DAC that we feel sounds better than the new MK2 and all previous MK1’s.

If you don’t have anything constructive to say or add truthful information to this discussion besides your negative remarks and comments please go elsewhere. Your negative comments are not welcome here.

You did the same thing with TurboTK’s (tekaudiospecialties1) post. You only criticize others work and don’t add to the discussion with useful information..

No... Sorry, you would be the last person we would take any "free business ideas" from.

 

The DSD DAC already sounded good, before the upgrades, and better after the upgrades. Of course there's always room for improvements, by upgrading more of the internal components. 

Finally, JKRichards admitted that for the DirectStream DAC to sound good, it’s not enough just to swap the transformers and do the simple Vocm mod. You need a good power supply for the analog board.

 

People on the PS Audio forum (including myself) already installed these power supplies 2-3 years ago. And previously, you, Jeff, argued with me that you could NOT hear the difference with the additional power supply vs. without.

 

Now, waiting [another 2 years?] for you to admit that the stock power supply needs to be modified for all these mods to really showcase their best. Because the stock awful noisy power supply is still there in your "Signature plus" version.

 

Here's a free business idea for you. Modify the stock power supply and you will have a Statement version, that you could offer for the price of a new DirectStream MkII .

@richardselectronics 

Following on that, about 2 years ago I had the then new PSA Gain Cell preamp which I found lacking a quality PS. I think the internal PS could be bypassed and a outboard LPS added. Seems right up your alley

Another interesting fact is the Signature series will accept and playback DSD 128 (DSD 2X) via AES XLR.perfectly however the stock unit will only accept DSD 64.

In this configuration we use both the factory Digital and Analog fuse locations.  You can pick your best digital fuse and your best analog fuse.  Digital is 1a analog is 5a.

We could not believe how real percussive instruments and vocals sound now with this supper low impedance power supply powering the important analog stages. We thought the original Signature series sounded better than the new MK2. We feel this new PLUS blows it away.

We are very excited to announce our Signature Series PLUS upgrade.

It includes our Signature Series with a very good internal linear power supply for the analog section. We even isolated the AC lines going to each power supply.

We have been working on finding the very best supply for this application and we feel we nailed it.

We use the complete bottom of the DAC for the heat sink keeping the internal temperature low. We use only the best capacitors and diodes available as well as using a high quality discrete circuit with a MOSFET (attached to the bottom of the unit) to regulate the voltage. The R-core transformer is icing on the cake and is very low noise especially with the thick copper flux band.

We finished our last MK2 transformer install yesterday.

Wow... Many flaws. All digital boards standoffs were completely loose. The bolt that holds the power transformer was not even tightened. It was moving around inside the case. The i2s inputs grounding tabs were not contacting the chassis, The ribbon cable to the display was resting on the power transformer, Three adapter boards were used on the SPDIF / AES XLR circuits causing a loud pop when switching from DSD to PCM. We have seen many of these adapter boards in customer units over the past 6 months.

These are just some of the reason we are no longer offering transformers for the MK2. We have found many other issues as well.

If you see these adapter boards in your unit you will have this loud popping issue.

Fortunately our unit we sold a few weeks ago did not have any of these adapter boards.

We are very excited about our new Signature Series Modded MK1 DAC.

Before the new mod the DC offset averages between 3.6mv and as high as 12mv. No unit we ever received here was below 3.6mv. Most were about 7mv or more. With our new DC offset tuning we get it down to 0.5mv or lower. Low frequency distortion is now much lower and the sound quality has increased quite a bit. We should start receiving reviews soon. We could not stop listening to ours last night.

They are back in stock now.