Salas SSLV1.3 UltraBiB shunt regulator

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Considering the improvement that it made on the Soekris, which is a hybrid "analog & digital" board, I'd dare say that it works well for both. :)

Especially for Soekris which asks for around +/- 10V rails, the regulator is in a good range for its M2 output Mosfets to have substantial voltage across for lower parasitic capacitance and there is good voltage space for all its active components. Thus the response and phase margin are at a more optimum state.

As it squeezes down to 5V applications all those voltages go down to just decent enough. That's why I noted better put less than 7.5mA IDSS J3 if for 5V output use. Not for it to have demanding for voltage space Vgs (off). From 6V upwards setting not even that suggestion matters. I have checked on the bench that all the parameters from its most squeezed 5V setting up to 40V are adequately stable and that is performing well through such a remarkably extensive setting range though.
 
Here is a quick and dirty assembly on one of my "standard" BiB boards. A combination of red and green LEDs and no pot gives around 4.9V.

This will supply the USB side of JLSounds XMOS transport for my AD1865 DAC. It has absolutely the same type of components as the "standard" BiB I use in there. This is to ensure proper listening tests.

After some burn-in, listening sessions are in order :hphones:
 

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Precarious experiment to mod another circuit & board towards the 1.3. It has high OLG, cascode, and CFP. Those are sensitive works. It needs some things be done exact and some parts to be exact. I see four wire mode in your pic. On Kelvin wiring it will be a pig to be stable if ever. If this experiment will be easily stable on Kelvin it means it behaves much differently. But good luck.
 
Kelvin wiring is just for compatibility with the original BiB board. In the case of V1.3 the connections are shorted on the board itself, i.e. no real Kelvin wiring ;)

Also I cheated with some smd resistors and transistors (BC860C, 2SK880GR).
 
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diyAudio Chief Moderator
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You should at least verify its basically stable without any AC gremlins on the rail by using the scope. Post#1 has a 1us/2mV 20MHZ limited picture I measured at the Ultrabib's +/- rails that can serve for your reference.
 
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George, nice. This shunt reg does not need high spare current to play well as you saw. But calculate load pk with your lowest impedance headphones for your DCG3's both channels to make sure that your common PSU's current limit setting won't clip at worst case demand. There is a guidance post I made about its consumption details named "Few words about power" #79 in the DCG3's thread: Salas DCG3 preamp (line & headphone) - Page 8 - diyAudio