Modding the PS Audio Directstream DAC MK1 and MK2

Interesting; however, the mkii sounds better than the mki.  That’s my listening comparison with both having the edcore transformers (no other mods).  Will hear the APS transformers in the mkii soon enough.

That may be true however without the Vocm mod and our nickel transformers in the MK1, it’s not a fair comparison. We have both the fully modified MK1 and the MK2 with our transformers, the input grounds fixed and 3M RF shielding setup to do instant blind A/B comparisons and most who listen here cannot pick a winner. They are that close. I can pick the MK2 most of the time however I know exactly what to listen for not necessarily the best sounding. They are both great sounding.

Hands down the build quality of the MK1 is far better than the MK2.  We are pretty disappointed in the build quality of the MK2 since we have been modding many of them here. Every one of them have / had build issues.

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.

The internet can be a weird place. I've generally seen negative comments about PS Audio DACs outside of the PS Audio forum so it's a little surprising that you've tripled sales after moving away from the forum. But it is possible that the website helped people feel like the transformers are more of a business and not just a thing where you message some guy and hope to get something back after dropping $600+. 

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.

If I had to rate the value of audio products purchased or mods I've done over the years, the APS DSD MkI mod is at the top of the list. It transformed a decent DAC into a total beast. The value proposition is off the charts. 

Hello folks, still here occasionally :) Thought I'd share some things.

The Vocm mod with JK high nickel trafos is quite good and would likely satisfy the majority of listeners IMO.

I will say though, the pinnacle of DS DAC mk1 sonic performance is, Diff amps topology mod (also found some diff amps I prefer to the AD803x), along with a bi-polar PSU that then allows for no caps or trafos on the output. This also allows Vocm to be=ground, so no mod needed for it anymore. It's not trivial to do but can be done, I'm listening to mine here now with it.

Now we're really talking, now there is no audible distortion (quite rare IME) and you are hearing the fw performance basically. Any further improvement would be upgraded fw. I asked if we could get a Mk2 version improved fw for Mk1 and the answer was no.

BTW I prefer the older Sunlight fw on mine; it's more open and dynamic and alive sounding. It's playing here now. 

I recall someone on the forum had done some topology mod effort, but they claimed they didn't like it. I don't know what the problem was there, and maybe I had also misguided somewhat with some poorly suggested values at the time. But whatever, I don't have the time or energy these days to try and maintain and acceptable S/N ratio of a web forum and that's when I called it quits there basically. The truth of it is what I posted above.

TK

Some other news, this summer I was able to get Tom C of Neurochrome Audio to do a special version of his Modulus "error correcting" amp boards (thanks Tom!). Notably, we eliminated the OA input buffer, and the input coupling cap (and feedback cap!) and added back a DC servo since its now DC coupled. IMO this should allow the most transparent Modulus you can do basically. I’ve been listienng to it for months (its playing here now with a new proto preamp) and it’s quite good in fact. Note that, with the OA input buffer gone the boards are single ended input only, which is fine. The amp modules themselves are also single ended anyway, as most amps are internally. And again, its fine.

However, for best results it does need the best OA we can manage for the "error correcting" portion, and for the DC servo. Most industrial OA are evil in comparison; discrete ones generally less so at least. I socketed my build and prefer the Sparkos SS3602 in the error correcting location and a Muses01 in the DC servo. Muses OA appear standard old industrial but they are far from it, employing a Cu leadframe for example. They put a lot of effort into these in fact and you can definitely hear it. The 01 is a JFET input and is very clean and quiet, also good for a DC servo IMO. The 02 is a bipolar input and "rocks" a bit more in comparison IME. But not as good for a DC servo due to input bias currents.

I have mine in a Naim NAP180 chassis with what I call a "super" PSU in it. I think I would recommend a good SMPS for it if DIY. As Tom says, with this much error correcting horsepower available the boards are somewhat immune to PSU, but still, better PSU is better in general.

If you want to DIY your own, ask Tom for the "Todd King" edition Modulus boards. I can recommend them.

TK

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.

Quote from tekaudiospecialties1

 

"BTW I prefer the older Sunlight fw on mine; it’s more open and dynamic and alive sounding. It’s playing here now."

Sunlight is the last firmware (newest) for the MK1.

Did you mean an older version?

Here is the order of firmware for the MK1.

FMC-09 6115 2014
FMC-10 9114 2014
Pikes Peak 1/2015
Yale  7/2015
Huron 5/2016
Torreys 7/2016
Snowmass 3.00 11/2018
Snowmass 3.04 11/2018
Snowmass 3.05 12/2018
Snowmass 3.06 2019
Windom  10/2019
Sunlight  **LAST** 4/2021

Any updates on the 8139 opamp modification WRT availablity and cost? Understood this is a send in your board modification. You have already performed the Vocm cap and nickel xformer mods. So pleased with this modded MK1, but if the 8139 opamps can provide further performance I’m interested. I suspect this mod will be an improvement, just not as night and day as the Vocm cap and nickle transformer mod, eh? 

Would enjoy hearing your opinion on Massive final.  I hear a major improvement.  

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.

Interesting post:

 @jk_richards Are the APS transformers for MK1 and MK2 wired differently? Ted is saying the MK1 and MK2 are different but it's interesting that they can both use the same Edcor xs4400 transformers.

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?

OOF. Yeah I installed my MK2 APS transformers without any issues. Luckily I don't see that random PCB sticking out from my pictures of when I opened up my unit.

If install properly you will not have any issues whatsoever. It’s realy not hard to install with the proper equipment. Pull old transformers and re-solder in the new ones in the same footprint where the old ones came out. No adapter boards or hack job needed.

Installing components like in the photos above is a sure way of making a unit fail. Drag soldering this type of package is a big no no in a production unit. It’s OK for prototyping however should never be used in a customers unit. Did they think no one would ever see this?

Because of the statements made by PS Audio about performance, We will be posting actual measurements of a stock unit vs a unit with APS transformers.We have already posted measurements with the APS transformers installed using the last massive firmware.  That in-house testing screenshot they posted is showing useless information as there is no actual data just a pass / fail. What are the actual measurements? We will soon see.

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.

Today a PS Audio technical service technician posted an advisory regarding modified DSD Mk II DACs (latest iteration).  Apparently they have had more than a few of these modified units come i for repair. The nature of the repair was an output transformer swap.  PS Audio is not saying what transformers were installed, who did the install, or if the installation was sub par.  These units are failing all PS Audio bench tests and the repair is a replacement bard with the original style transformers installed.  As the affected units have been modified the repair is not covered buy warranty.  A link to the thread provided in the PS Audio Forum is provided for reference: 

https://forum.psaudio.com/t/dsd-mk2-aftermarket-modifications/36378

@weedeewop this was posted 5 posts up

Missed it, but here it is again.  No harm no foul....

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

This hack job is why.

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.

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.

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.

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.  

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".

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. 🤔

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 

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. 😞

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”

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..

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"

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

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.   

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.

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 job is way better then you did for some poor lad

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.

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. 

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.  

This is how we do it.

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.

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.