Just a heads up… Only one pair of adapter boards available from this first batch.
If we get more interest we will run another batch
Thanks!
For the USB stub plug. Will shorting Pin1 +5V to ground cause any issues to The DS? Does shield need shorted to ground too?
The removal of L1 and L2 near XMOS are they identified on the board with ref des labeling and are the labels visible?
Theoretically shutting off XMOS if USB is never used on my DAC sounds like the quieter solution but harder to restore. Right now it is covered with 3M absorber with shield layer outermost. The bit flipping looking for input does that tax other processing and add noise or slow things down
Just tie pins 2 and 3 to pin 4, leave pin 1 floating.
L1 and L2 are clearly marked:
Most probably the USB inputs won’t cause excess noise, the XMOS chip should recognize that nothing is connected. Still it’s cheap and easy to remove doubt with a simple connector. Removing L1 and L2 will very probably be audible to most.
The floating I2S inputs are more of an issue. I’ve seen them acting up on the scope now and then.
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Thanks Ted. I will remove the inductors when the LL1948s installs. In meanwhile time to destroy a printer cable and cheap HDMI cord and see what each does.
@Turbotk
@tedsmith
What configuration would you recommend for the primary coils on the LL1948 transformer. Series or parallel? On the boards I’m assembling I would like to pre configure this option. I think you would get slightly higher gain in parallel mode with slightly higher distortion.
Thanks.
Wait! I think you’ll get better results if you destroy a dragon cable… 
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I think this is a very clever idea. Please report back.
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I guess I’ll order a Firebird for that purpose. Lol
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Parallel will have essentially twice the gain. The DS is already 3dB quieter than standard so loosing another 6dB probably isn’t what most people want. If you have a good preamp it might be something to experiment with.
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Ted is the mastermind. I just think up questions to ask the pure genius brains. Not sure why that one popped in my head we all get tired of waiting for Td’s best designs. .
Sort of like my other tweaks. You get lucky going outside the box for answers on how can I improve what We currently have. Which already sounds amazing. But I am sure if it can be heard my system will expose it.
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Have you tested it yet?
How about now?
Are we there yet?
Thanks Ted. I agree. At least we can change that option later. I think Turbo is on the same page. I have my Jensen”s in series however I’m using a very good tube preamp.
Somewhere I have a USB cord that was a Matrix freebie. I think I might have taken all my HDMI cords over to our ranch house in a box of patch cords and wires. Needed them When I was setting up HT and music systems. The bad part is we rented out the ranch on Air BnB for 5 weeks and i hate to intrude on the guests. There is another family and a reality TV show and group of internet influencers that want longer term multi month leases and are willing to pay absorbent rent to live surrounded by horses. I thought the wife was crazy to sell three homes to buy that horse ranch. Now its earning double the income of the combined rental properties she sold to buy it. Lesson learned. Never underestimate your lady.
I may have to do a Walmart run to make some cheapo shorting cables. Might not see my box of cheap cables and speaker wires for a bit otherwise.
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I have the LL1948 primaries in // on the DAC1.
BTW DW is bringing DAC1 back home this weekend. He’ll be dropping by to pick up his new 2.4se, and do some listening here. We will compare DAC1 vs where DAC2 is currently. It should be very very interesting…
Speaking of interesting… The last day+ have been a deep deep dive into bit shape and THD+n. Yes the bit shape absolutely matters here. It all started to sink in heavily when I would hear audible hiss when the OA gain settings were not right for example… How was this happening? Squeak squeak goes the hamster wheel… 
Turns out the OA gain setting was still too much (feedback R off by 100R) and the OA buffered bits were running a bit erratic. Along with the edge rate control thing needs serious re-thinking. Again, we have to learn a lot on the fly here if we want to maximize this result.
And fortunately I picked up a THD+N meter years ago (disregarding the old AP system 1 that sits in storage Dragged the meter out today and got some baselines… Was surprised to see the DAC2 is already ringing the bell with some -12dB better than the Termi+ that happens to sit nearby on the same 1KHz THD+N measurement. BUT the simulations today at least are promising that much more is likely possible and we’re on it full blast… Hope we can! T
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It looks like this is a tiny pin continuity check to insure I only tie together pins 1-12. I was hoping it would be terminating the lot but I see there are 19 pins. I found one non audiophile cable with a choke installed. I will do a practice termination termination tie past the ferrite choke.
Any pins worrisome that could damage the DS?
I’m not sure I understand your question. Tying pins 1 thru 12 together is what’s needed to best calm the I2S inputs. Don’t hook power to ground 
The I2C lines are used to detect levels and do not drive anything that can induce noise, so they too should be left floating. There’s no need for a choke or anything else than tying pins 1 thru 12 together.
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The plugs I have are all molded and on a cable.
This is the ticket to make these in mass versus trying to do continuity on 12 pins
Screw down 12 wires and crimp and solder.
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Please post a link for that. Intriguing…
Nevermind, I was being too lazy, found it. Thanks!
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Two of them will be here on Saturday. Prime is my friend, but I think it might be causing a heatwave.
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I’m so lost… the I2S schematic picture shows an LVDS driver… Yet the DAC I2S input port would need to be a receiver…
“DS90LV031A is a quad CMOS differential line driver”
OTOH it could be just to illustrate the corresponding receive side pinout.
Or I suppose I’m just having another senior moment I had jello today! T