Modding DirectStream DAC MKII

Are you trying to volume match the two for comparison?

Without a db meter or a volt meter, that’s gonna be tough.

yes exactly

Well, I would think that since they are digital, the output would be known

It’s a bit more complicated then that.

How so?

You need calibrated equipment and knowledge of how to do it.

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I guess if you want something thats specifically accurate. I just want to be able to compare what I hear between the Jr and MKii, if anything.

Using the same volume is the easiest thing to do and will make a difference in what sounds subjectively better.

The human hearing can be fooled.

of course it can. hence why starting with the right volume helps to minimize variability without an electrical engineering degree

Sorry. I have nothing else to add

You seem super interested in getting this right. I really suggest you buy a db meter. It will help you with what you are currently working on, and you can use it to see if both of your speakers are putting out the same db at your listening position. You can find them for as little as $20 on Amazon. I don’t know how good they are at that price, so read the reviews.

Have fun!


@jkrichards, should you hold off on the MkII trannies until this fix gets rolled out?

It won’t effect anything we are doing. This is because our transformers are doing what a 1:2 transformer should. No way would we make our transformer less efficient. (Another reason ours sound so good)
The only way to get 4v out of the Edcors is to increase the voltage going into them. I believe that’s what they will do. If the voltage with our transformer goes higher then 4v it’s just a matter of turning down the volume which is also a good thing. Currently with the volume set to 97 it’s 4v out. We may have to lower it to maybe 94 like in the DS MK1.

V to dB


There is a 0.34v loss using the Edcore in a 1:2 configuration because the secondary coils are now in series. 100 ohm + 100 ohm = 200 ohm total with the center tap connected between the two coils.
The primary coils are in parallel 100 ohms / 2 = 50 ohms. The gain loss comes from the very large secondary windings. This 200 ohm is also stated in the spec page for the MK2.

What does SW100 do? Assuming it is a duplicate power switch.

It’s just a non-dedicated switch hooked up to the processor for ease of debugging. I don’t know what it might be used for in the currently released software. I use it to cycle tests in the FPGA.


Thanks Ted. I was tempted to push it however I didn’t want to let the smoke out :smile:

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Can you share the plots here? A bit hard trying to zoom in on laptop screen

Sorry. We won’t be sharing any plots or other info at this time. It’s still early in our R&D. We will be showing plots of our transformer sweeps as soon as we are finished.