Fortunately it only takes about 200 hrs to fully break in.
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Hi all,
happy to join the modding-community here 
Request for OpAmp Buffer and AD8139ARDZ photos and more details:
Today I gave my friend who is an electrician my DAC MKI DirectStream. However he is no audiophil/not really into this and asked for a few mods for a more detailed description on what he shall solder exactly. Hope a handy modder can help me out.
OpAmp Buffer: wiesiek did this mod w/ a Sparkos discrete OpAmp (DIP8 socket). However I only have this one picture and a more in-general description.
In my system, the output buffers make a very big change. Previously, they were mounted on OPA1632 op amps and were outside the DSD. Currently, buffers are assembled on Spakos SS3602 discrete op amps and placed inside the DSD. The buffers need a symmetrical power supply, so I installed a transformer and a +/- 12 V power supply with Hypex HP (N) R12 voltage regulators.
AD8139ARDZ: How does one do the replacement of the AD8132 - especially w/ the higher ampere-requirement and the need of a seperate voltage conmtroller? Any photo and description is highly appreciated
I noticed that Ted often replys here and I find that really cool. So, I give it a shot w/ two questions:
- Doesnt the FPGA also requires a clock signal and wouldnt it make sense to put a OCXO here or perhaps a seperate voltage controller?
- Does the directstream also upsample DSD64 DOP?
There is one master clock (actually a VCXO) on the analog card. The clock signal is sent to the FPGA and then the FPGA returns the DSD data in sync with it to the analog card. OCXO’s aren’t appropriate here. They are designed for long term accuracy which is irrelevant to audio. The goal is the lowest near-in phase noise and the VCXO that’s in the DS is one of the best you can buy. Also OCXO’s don’t have the flexabilty to lock onto valid Redbook sample rates which are +/- 100ppm from the nominal rate. OCXOs (OCVCXO’s really) typically have pull ranges of a few ppm.
The FPGA is on the digital card and does have separate voltage regulators than the rest of the digital card and the digital card has separate voltage regulators than the analog card…
DoP is how the DS keeps DSD internally. Yes DSD64 and DSD128 are upsampled, volume adjusted and converted to DSD256 for output.
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Thank you Ted.
Regarding AD8139 mod - I hope the question is not too in layman’s terms:
Can you just drop-in the AD8139 and connect the V+ and V- to a balanced +/- regulator? If i understand it correctly 8139 and 8132 are pin compatible.
The local regulators and power supplies also need upgraded with the AD8139.
Upgrading the opamps is complicated. You need to understand that you need to remove the current opamp regulators (and their caps) and make sure no voltage/current backfeeds into the board. If you want a balanced supply, it needs to be isolated since the current opamps have their negative supplies firmly connected to the board’s ground plane. You also have to deal with the input’s common mode voltage.
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Do you have a link to good replacement parts for those + did you do that mod already and have photos of what you changed exactly?
Just a comment from the sideline if you’re in the US (I’m not):
I think with the US deals possible, from a certain point of effort and upgrade cost on, one should think about going to the Mk II. The Mk I with all upgrades except the opamp one is already extremely good sounding, not many will need more, even in a big setup. I think those upgrades are already on the edge of being cost efficient compared to a Mk II in the US. The opamp mod seems to generate quite a risk to it, at least for someone who’s not very sure how to do it.
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I know you probably weren’t asking me, but replacing the AD8132’s with AD8139’s isn’t a “replace parts” kind of mod. There aren’t places for any of the new parts (except the AD8139’s), everybody has their own idea of what a good new power supply might be… The AD8132 and AD8139 differ in a few ways that have tripped people up (including me.) and the speced current draw is lower than what we are seeing with the output levels expected.
The DS was designed to accommodate the XS4400 transformers. It was designed for a generic 12V power supply. Adding caps and replacing some resistors is easy for someone used to surface mount reworking. It’s not at all designed with the expectation of replacing the AD8132’s and there’s nothing out there that is a drop in replacement.
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How about we apply @yuriy’s method?
A tool called a “solder sucker” or a solder wick will make the removal of parts easier.
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We are going to make a daughter board with the AD8139, filters, regulators and a bipolar power supply. We would then just make a few connections to the existing board and just leave the old parts in place. The 8132 are hard to remove without special SMD tools.
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This is the way.
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Do you expect the sales price for it, added to the parts and work price for all other mods (analog PSU, VOCM, transformers) make sense cost wise compared to a replacement deal for the MK II?
Sorry. This is just an in house project.
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Ok, makes sense…I guess it would be a little too expensive for sale….on the other hand sooner or later you offered a few other firstly in-house mods for the DS in the past 
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Does it mean in-house, in-forum? 
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In case you followed every step of development (external LPS, DC-board, XS4400, Lundahl, APS), as I did, you may be right. But everyone who owns a stock DS Sr. or can get it 2nd-hand in good shape, add 600 bucks for a pair of transformers, another 200 for caps and other bits and pieces and a helping hand and you are miles away from the cost of a Mk2, especially in Europe (near 10k€!). I will not guess how close you get to the SQ of the Mk2, but you are still roughly at a third of its price tag. A bargain, I would say!
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That’s why I wrote “…if you’re in the US”
I’d say, 1k for external PSU like Farad with DC cabling, also inside the DAC etc., 600 for transformers mounted, 200 at least for SMD works/parts on C704 and VOCM caps/resistors. Makes nearly 2k €, £ or $. Not included an add. AC power cable for the PSU. We must take into account that many had their first mods done when the Mk II was still half a year away.
In the US I understood, a Mk II in Exchange for a Mk I is 3,5k. This is where I’d say a modding of a Mk I in that way makes little sense, especially if another opamp daughterboard mod would add to it, which I guess would at least be another 500$.
In Europe things add up differently, as there are no Mk II deals at all and prices are 2k more, so a Mk II, even if a Mk I could be sold on the open market, would make 6-7k on top of that sold Mk I.
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Awesome! When might the new board appear? I basically did all that by hand in my DAC#1 (plus more). And DAC#2, similar except still a 1 pole supply (but higher voltage, beefed up, etc).
BTW I am truly enjoying DAC#3 with your new trafos (thanks!) and just the VOCM mod. I have it direct connected to the amp(s) currently and loving it. Your trafos do sound marvelous. Nice work! I think a large capacity core does help (and of course high nickel as well).
I’m still not sure about direct connection in terms of dynamics… but I LOVE the natural, organic, musical purity of having nothing else in the way…
BTW I also have a pair of Focal Kanta No3 now, which is a substantial upgrade vs what I had before. Loving them! Also allows me to hear even much better what is playing into them, all parts. There is just no distortion coming from that beryllium tweeter, and the flax cones seem to be special indeed. The whole big thing “just gets the h-ll out of the way of the music” ™, very well basically…
Still pondering the best solution in terms of dynamics AND natural, organic, musical purity. Thinking cap is on hard core the last several months. I’ve also spent alot of $ in the process trying things.
Speaking of, I have been exploring preamp options. I have an ic0n 4PRO AVC on the way as well. We shall see…
What I continue to find is, most power amps, regardless of cost or rated power don’t do low bass properly. I only hear it properly done when I use my own proto amp, which has extensive PSU work and attention. And this has held vs at least about 10+ different other amps by now. Anyway… T
PS- pretty good review of the Mk2: PS Audio Direct Stream DAC Mk2 Review - YouTube
An aside story- they’re gathered around a Lumin streamer in the review, not unusual. I hauled my CDT3 to the local Focal powered by Naim shop to audition Focal; had a hunch I would need it to be able to hear what the speakers can really do. Spent a whole day there basically. They were open to trying the CDT3 vs the Lumin streamer they were using and it quickly kicked the cr-p out of it complete with some dropped jaw action, as has become the usual result. The shop was quite surprised, and it played the whole rest of the day. It truly is one of the best sounding sources available. Friend DW has been trying to find something that beats it, but has been unable to so far.
The ability to provide subtle shading and tonality and contrasts that usually just goes missing is what is most impressive (the DAC, and the system via the direct connection). It makes the music alot more real sounding and enjoyable. As I often say, just get the h-ll out of the way of the music please.
The DS DAC is also much more rhythmically correct, as we’ve said before.
DAC3 with JK trafos; system doing a remarkable job of “getting the h-ll out of the way of the music”:
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