Modding the PS Audio Directstream DAC MK1 and MK2

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

Can we purchase APS stickers like the ones shown above? You installed the Vocm and your nickel APS transformers. I do not consider it a DS anymore and would like to have a way of showing. Sent same message on your website.

Hello Guys.

Has anyone used silver bearing conductive adhesive instead of solder for the caps  with the Vocm mod?

There are some very low resistive ones to chose from and easy to apply without the danger overheating the SMD. Durability does not seem to be a factor according to the manufactures data sheet.The adhesives are not cheap but neither is a new board.My most concern is with sound quality.

Thanks .

Quote by georgeab

"Can we purchase APS stickers like the ones shown above?"

We started using these badges on our signature series DAC upgrades where we fine tune the DC offset and use the newer revised transformers in the MK1.

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.

Hi Jeff. Was this evaluation done on a MkII with your trafos, or a stock unit, or both?

With our nickel transformers and stock. To us it sounds like a fake top end and lack of low/mid dynamics.

We like fpga1_208_Antero best. We also feel that both the MK1 and MK2 needs a preamp to sound it’s best just like most other DAC’s.

Do both the MKI and MKII use the same software and firmware?  

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.

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.

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?

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.

@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

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 .

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. 

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.

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).

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

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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

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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.

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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.

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.

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?

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

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

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.

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!

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.