Modding the PS Audio Directstream DAC MK1 and MK2

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.

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

@weedeewop this was posted 5 posts up

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

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.

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.

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.

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?

 @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.

Interesting post:

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.

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

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? 

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

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.

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

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

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. 

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.

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+. 

And our nickel transformers.

Here is the Edcor XS4400 in 1:2.

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.

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.

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.

Here is an FFT of our modded MK1 with our nickel transformers.  Much better than the stock unit and the new MK2.

The weird thing is we have tripled our sales since leaving the PS Audio Forum and opening the website.  Should have done this a long time ago.

Below is a Post by Elk on the PS Audio Forum. He can’t even be honest with the forum members over there. He knows I can’t post on the PS Audio Forum to correct false information.

He did in fact delete any post that praised our mods and / or post that showed any flaws in their product and how to fix them since the new MK2 was launched. As a matter of fact, PS Audio is currently using my fix for the latest FLAW the dreaded input grounding clips.

The last one was the one I posted here on this Forum.

https://forum.audiogon.com/posts/2586529

I have many screenshots to prove all of this.

He even locked down the modding topic after this was posted.

Elk

Ordered! Thanks!

You will only get an invoice on checkout.  Further information will be sent. 

Ok, so I put everything in my cart on your website, pay for it all, and then in November you reach out for me to send in my dac? Nothing on the website indicates "preorder", so just want to make sure I follow.

no.  We get an email when we get a message. 
Only doing pre orders now.

Thanks for the response. I’m not sure what "I’m doing wrong" either. I’m not tech illiterate, I promise. So you don’t see my message in your inbox? FWIW I don't see where to check inbox in the forums. You have to go back to main audiogon website (delete "forum" in the url) to view messages

When you say backed up till November, does that mean I need to reserve a spot now or just wait and check back in November?

Not sure what you’re doing wrong as no one else is having issues connecting with me using ether method you state. Have communicated with many people with no issues.  I’ll PM you now. We are backed up till November. We did add the Ag 1948. A little bright for our taste however some may like them. We also added a network isolator for streaming. We are quite surprised how much improvement it makes.

I’m looking to get these upgrades for my MK1 and have tried getting in touch here via private message and the contact form on the website. No luck yet.

I see today I have another transformer option. I thought I was set on the nickel but see the is now the LUNDAHL 1948Ag Pure Silver windings Transformers. How do they compare between the two?

Thanks Jeff. My takeaway from your response is that you recommend using a pre-amp. I'm good with that.

I don’t recall us making them exact statements. The Custom nickel transformers do in fact increase the output level by 6dB because they are and were designed as a 1:2 transformer instead of the original 1:1 transformer that are installed in the MK1. We did state that The Custom nickel transformers have a much lower output impedance than the MK2 Edcor XS4400 transformers which places the secondary windings in a series configuration in order to achieve a 1:2 output which creates a very high output impedance. This was kind of a cheat as the Edcor XS4400 was not designed to do so. The Custom nickel transformers are designed from the ground up specifically for each model, The MK1 or the Mk2.

The lower impedance is a plus as it in theory should have a lower noise floor going directly into a power amp. We never tested this as we recommend going through a pre-amp.

Hi Jeff, one of the reasons I'm considering your transformer upgrade for the MKI has to do with connecting the DAC directly to my Pass amp. I seem to recall you saying that your transformer upgrade increases the output voltage, which helps when you connect the DAC directly to a power amp. I haven't noticed anyone talking about this lately so can you please comment on this? 

They have been shipping continuously to pre-orders.

What's the ETA on the next shipment of transformers?

Unbelievable... It took PS Audio forum members over a week to discover and discuss this problem after my post exposing this issue was deleted by Elk. The ones who have the tabs missing or loose... This is not an easy fix as they rip off the copper foil when they come loose. All units I have worked on here had this issue. Even brand-new ones that have just shipped. I knew it would eventually catch up to them and be exposed and many questions asked by unhappy customers. PS Audio should have done the right thing from the beginning instead of trying to hide the issue.

https://forum.psaudio.com/t/directstream-mk-2-observations/31566/2602