EAD? How old are those guys?
How old is Richard Vandersteen? How old is Dan DāAgostino? How old is Peter Lederman?
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ā¦Jeff Rowland and Nelson Pass.
A certain Paul!
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Wow that daughterboard w/ A8139 sounds intriguing. I would love to get one.
Perhaps with the option of just the A8139 w/o the power supply is possible.
Why the option?
I couldnt find a complete step-by-step how to do the A8139 mod rather various posts. So I settled for an intermediate step of which later the power supplies can be reused.
Question regarding that intermediate mod:
So, until this daughterboard (fingers crossed) comes available I would like to do a mod by yuriy.
The mod seemes less complicated and the description is very complete (post 3139). I hope you guys can help me with one additional question here.
My question:
What voltage regulators to use exactly - one positve and one negative (and on which side which one)?
The original description:
The first stabilization link to 11V I used a stabilizer on the LT3042 chip. The second 7V stabilization link I used was the Ultra Wideband Low Noise Regulator from NewClassD from Denmark. Its output impedance is about 0.030 ohms up to 250kHz. I installed it directly on the board, where, on the recommendation of @tedsmith, the Q700 pass transistor was previously desoldered.
A friend does the mod but asked me to take care of ordering the right parts and get the info on what to do. So I hope you dont mind me asking obvious questions 
I donāt think he is using a bipolar supply.
Is it just me or is this thread in a different language? 
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Yes, this is what confuses me:
- He is powering the AD8132 w/ those two voltage regulators
- AD8132 requires + and - voltage but does that work with two positive regulators?
Iām at a loss 
You need to start from the beginning of this long topic so you have a good understanding of the circuits.
That 7V is split into two 3.5v via the two 500 ohm VOCM resistors (marked 10.0k in schematic) in each opamp circuit. Analog Ref. is the virtual VOCM.
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8139 solution how many years ago. Is there a better solution than 8139?
jkrichards,
Out of curiosity, are your version of the transformers going to be hand made/or machine made?
Either way, is there a target % of garanteed variance compares to your designed curve? From sample to sample? Thanks!
No. More recent differential opamps mostly use a 5V max supply instead of a 12V max supply.
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All are hand made and have very tight tolerances. We sweep and document all transformers. All transformers will be at least as good as our spec states from earlier post. All transformers have a serial number that matches the sweep provided.
My son winds them on his automated winding machine so they all have uniform windings.
I have been stacking the nickel lamination, installing the flux band, and testing / printing.
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Very cool Jeff.
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@tedsmith Does the MKII have a bipolar power supply for the analog board? I only see 2 yellow and 2 orange secondary winding wires going to the analog board. I havenāt probed around as it is not my unit.
I have no doubt that this transformers are the best possible upgrade for the DS, together with the VOCM mod. And, what is more, I am absolutely convinced that at the Richardās team true passion meets profound knowledge. And I can barely wait for the transformers to arrive here. The DS is patiently waiting to be completed. In fact, it is much more patient than I am. But Iām sure itās worth the wait.
So, @jkrichards, keep your curiosity and creativity.
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The power supply is described in the first DS vs DS Mk II thread, if you havenāt perused it there are probably some details that youāll like, if you have read my posts in that thread about the power supply, Iāll be happy to answer some questions.
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Thanks Ted. The photos of the schematics are too blurry to really see. Maybe itās something on my end.
The schematics in the first post are blurry. They were just there to illustrate that the Mk II has a little more in it than the Mk I. There are a few post aways down that explicitly talk about the power supply, probably no schematics, but itās not a bridge/rectifier/caps/filter kind of power supply. It takes pains to draw current pretty evenly over the AC cycle, e.g. its got a pretty good power factor.
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Thanks Ted. You are awesome.
It would be great if all manufacturers did the same thing.
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