Modding the PS Audio Directstream DAC MK1 and MK2

Attached is a sweep of the LUNDAHL LL1948Ag (silver) transformer for comparison. These transformers are some of the best and most expensive units made however are not that good in the DS.

Here is the Edcor XS4400 in 1:2.

And our nickel transformers.

 

Agree. Thanks for posting this. We feel these transformers are a much better investment than say $1000 power cables and it’s immediately noticeable and measurable.

The MK1 upgrade makes a lot more sense for many instead of the large investment in the MK2 which they still have not moved past Beta testing even thou they are and have advertised it as a "ready for market" product however we feel the MK2 transformers are a must over the currently configured Edcor’s being fitted in the MK2.  Look at the sweeps we have done of each.

Good hearing from you Todd.  Your mods look quite good.  JFET's have been popular for high end audio for quite some time.  I used them in a tube preamp I built many years ago.

 

I’m kind of on the fence.

Using a preamp, we feel Firmware fpga1_208_Antero or the first fpga1 228 Massive sound better. The new fpga1 233 Massive is clearer and can have more detail and a larger stage however for us just doesn’t sound as "real". Just a little thin sounding for our taste. String instruments have lost their body and texture.

We of coarse did instant A/B listening test in our evaluation.

The UI update is great as now we can turn off the power to the WiFi chip inside the unit. The sample-rate screen is also welcoming.

Look up Weedeewap.  See the real reason these units are failing.

This hack job is why.

 

Yes they are different. The Edcor XS 4400 has 4 windings that can be configured in several ways. (4-center tapped coils. 2- primary and 2 secondary). PS audio just uses the two secondary coils in series without using the center taps. They use the series junction as the center tap. The Edcore is a cheap ($30.00) off the shelf transformer that can accommodate many devices. These Edcor transformers were not designed to do this however it seems to work however with a great loss. Ours are designed specifically for the MK2 or the MK1. That’s why they sound so good. Our transformers designed for the MK2 will not damage the analog board whatsoever as PS Audio is claiming in the link above. It’s impossible unless the technician does it improperly. We have been running our MK2’s continuously for a year now with no issues. We have many customers doing the same also with no issues. Our extensive testing using state of the art equipment shows better performance using APS transformers unlike the statements in the link above.  Using a properly installed APS Audio nickel transformer will NOT damage the board however an off the shelf transformer can as it would not have the correct wiring. This is a passive device that improves the sound quality of the MK2 by a large amount just like the ones designed for the MK1 which are a different design

This is so ridiculous as PS Audio contacted us and wanted us to license or sell them our transformers. I can post emails from them if necessary.

 

 

Here is the real culprit of failing analog boards in the PS Audio MK2 units.

Hack job hand soldered adapter boards being installed at PS Audio. Guess they ran of the proper parts so they hacked this in instead. If I paid the kind of money these units cost and found this I would be very upset.

 

Shall we say more?

Quote from driftingbunnies

 

"Luckily I don’t see that random PCB sticking out from my pictures of when I opened up my unit".

If anyone opens up their unit and see’s this just put it back together and ask for a replacement unit. It will eventually fail without any help.

 

I would know first hand if even one unit failed that we installed transformers in.  We have had none fail. They must be talking about someone doing a self install of some others transformers as we only sent out (2) two pairs for self install.  One has already commented here. The other is still going strong.

We did turn down one unit and refuse to install which had this hack job done to it.

As promised. We were busy yesterday measuring the Directstream MK2 DAC.

I knew we liked the previous Massive Beta best (in blue below). It measures and sound best to us.

As promised. We were busy yesterday measuring the Directstream MK2 DAC.

I knew we liked the previous Massive Beta best (in blue below). It measures and sound best to us.

 

 

 

Notice the HF roll-off on the stock unit Compared the a unit with the APS transformers installed.

Quote from emailists :

"This might sound crazy but maybe some of APS's customers can thrown in $40 each and buy Ted a pair of APS he can play with on a spare or pre production MkII.  I think it would yield better updates if Ted could also hear what it sounds like on a nicer transformer."

Unfortunately this will never happen with the MK2 or any other product they sell.  They have to fix issues with the parts they have already released.  Ted would not be alowed to do any programming changes on units with "non-official parts".

 

Your welcome.  You should give Firmware Snowmass 3.0.5 a try.  With it the MK1 will sound even better than the new MK2 with our transformers installed. It's the most musical sounding firmware ever.

We are deciding if we will even offer transformers for the MK2 any longer.  It doesn't deserve our transformers. PS Audio is causing us more headaches with all the flaws the MK2 exhibits. It's not easy telling customers that they received a bum unit that they need to send it back for a replacement unit before we would even consider installing transformers. 😞

OK... We have only 3 pairs of MK2 cores left and will not be offering them any longer after they are gone. 

Was browsing this AM and found this hack job.  This maybe worse than the first one posted.  At least he is not selling this for retail.

 

Vocm mod 🤣

 

This is how we do it.

 

Here is three of the five we compared.  The stock units are gone.

 

No.  The transformers are even different. .

We have decided to build and offer our external power boards.again.  We have many request for them.

PM if interested.

 

 

 

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.

 

 

The green LED indicates the external supply is power on and being used.

 

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.

 

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 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.

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.

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.

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.

 

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.

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.

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.

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

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.

 

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.

 

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.

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"

 

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 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.

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

Quote:

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.

 

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.