Modding the PS Audio Directstream DAC MK1 and MK2

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.

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

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.

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.

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

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.

No.  The transformers are even different. .

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

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.

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?

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.

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 .

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.

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

I don't have an inferiority complex, and I easily admit when I was wrong.

Ted Smith has called me out for not knowing what I was talking about and wrongly assuming circuits and design AS MANY TIMES as he called you out [or any other (proactive) modder] on the PS Audio forum. It's a trial and error method.

And it doesn't make me wrong in the design of my Vocm mod.

Thanks George for the support. Yes, this is a complicated design with sandwich using different types of capacitors to cover wider frequency range. The electrolytic capacitors here literally have no legs at all so no parasitic inductance added. 

And support eliminates microphonics. 

Also, my audiophile friend and I (both with APS and full list of modifications)  prefer Windom over all versions of Snowmass FW. 

Windom sounds like multibit DAC, Snowmass is like a good delta-sigma.

This is how we do it.

Spent a day revisiting the Snowmass 3.0.5 firmware in my Vocm APS xformer modded MK1. In my system, in my acoustic environment, and my ears I prefer Sunlight. Just my experience, YMMV.  

Must have been a difficult decision coming to the conclusion of no longer offering APS transformers for the MKII. A real loss for the MK2 community. Hopefully, when PS Audio gets its production issues sorted, you may consider revisiting the decision. 

Going to give the person some credit. First, they used nickel core APS transformers. Had the right idea on the Vocm mod, just the execution of not using suface mount and creating antennae. The added structural support for the capacitors is creative. Likely sounds good.

This job is way better then you did for some poor lad

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 🤣

I forgot to add the MK2 with the Antero firmware.  It's also a "10"

In modded form, We feel the MK1 and Mk2 with the above firmware sound almost identical.

No one here could tell which DAC was playing.

Wow this is too bad.  I'm trying to convince a friend with a MkII to have the transformers installed.  Maybe once I get mine back and hear them I can convince him.   

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

Here is our new assessment.

“We feel the new firmware made a large improvement in sound quality.

If I had to put numbers on it from 1-10

Stock MK1 6

Modded MK1 9

Stock MK2 with old firmware 7

Stock MK2 with new firmware 8

Modded MK2 with new massive firmware 9

Modded MK1 with Snowmass  10"

That older info was posted before the massive final was released and with sunlight firmware installed in the MK1. With ether the current  massive or massive beta installed on the modded MK2 and Snowmass 3.0.5 installed on the modded MK1 we feel now the MK1 sounds better than the MK2 even with the better sounding beta massive installed..

The graphs are of interest; however, difficult to correlate to what one will hear. I found Mr. Richards numerical assessment of the sound quality improvement (see below) to be spot on. From my experience doing multi thousand dollar upgrades a worthwhile incremental upgrade of 1 is an excellent upgrade. For the MK1 the Vocm and APS nickel core transformers sound quality improvement going from a 6 to 9 is in line with my experience. Not a subtle upgrade. So happy. If I had not experienced, I simply would not believe the level of performance at this price point. Look forward to hearing from others with the MK2 to see if their assessment is similar.  

“We feel the new firmware made a large improvement in sound quality.

If I had to put numbers on it from 1-10

Stock MK1 6

Modded MK1 9

Stock MK2 with old firmware 8

Stock MK2 with new firmware 9

Modded MK2 with new firmware 10”

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. 😞

Just a quick note to mention that my fully-modded Mk 1 just seems to get better and better.....  Honestly, I fire up the system with the intention of listening to vinyl and after warming up on streaming files (Roon ROCK NUC, Allo DigiOne Pi) I am quite literally floored by the sound quality.

It is superb in all aspects, so much so that I really find it hard to fathom that the stock MK2 would even equal it.  I'm really glad I got the mods done when I did!  to quote GME109 from a previous post "It transformed a decent DAC into a total beast. The value proposition is off the charts. "  I couldn't agree more.

I got tired of waiting for the AirLens and didn't make the beta cut, so I'm happy I didn't pull the trigger on one of those as well.

Thanks again @jk_richards 

FYI... In the several posts above with no photos showing, for some reason you have to "click" on the blank area and the photo will show. 🤔

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".

I should have my MKII with APS within a week. It’s been a bumpy ride (I was in the first or second group to order and pay) but Jeff has been great throughout all of it. I’m really curious to hear the MKII sound it’s absolute best, as my TAD speakers + Subs and super tweeters are quite revealing and phase coherent. Even with all the noise drama (currently not using a preamp, so didn’t stay with Massive beta), I’m still a strong believer in what Ted Smith and PS AUdio are doing. I really like we can choose flavors in the different firmwear available, and I’m really thinking that MKII/APS is going to be a great platform for a reasonable cost (especially used/trade in) for those willing to take the trip.

Plus Ted has all sorts of ideas for future releases including one fpga for left and one for right, or putting the sigma delta on its own chip.   

There's no telling what he might unlock in future experiments, and he can compile them much faster in the MkII, to better compare versions.

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.  

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.

We also would like to clear up a roomer that has been going around about our MK2 transformers making units run hotter. This is false. One of the tests for these transformers was a temperature test. A unit with our Nickel Transformers installed run the exact same temperature as the stock unit with the Edcor transformers. In fact our transformers are more efficient than the stock Edcor. This is why our transformers have more gain (accurate 1:2). Many PS Audio forum members complained about the hot temperatures on the bottoms of STOCK units before we even launched our transformers. One reason for this is some are leave the clear plastic protective sheet on the lids of their units. Leaving this plastic on is a big problem as the only space that hot air can escape it through the Perimeter of the lid. The edge of this clear sheet covers this venting up.

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.

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

This hack job is why.