The simplistic Salas low voltage shunt regulator

[Salas]

Originally Posted by johnm

I used 4700uF Nichicon KG with Qspeed diodes, and on the shunt PCB 220uF Elna Cerafines. Been very impressed with the latest black-skinned versions of the caps. Guessing they've been subtly improved over the years. Actually prefer these to Black Gate standards now. Looks like I got lucky with the component synergy - really powerful, but natural reproduction. Hugely involving. Dare I say it, the DAC is sounding pretty damn close to well mastered vinyl now

You can't run an Aston Martin on dirty petrol, can you? Its the same with PSU juice. Must be clean. When shunt is high octane also.

[Salas]

Originally Posted by Dr.H

Can you recommend MOSFETS and transistors for a 100Vin, 75Vout?
Then also for a 75Vin 38Vout?
Can we use 2sk170 in these as well?

This config should do theoretically. For 75Vin & 38Vout R9 should be 24K, R6 8.8K, C2 50V. For 75Vout R6 can't be a trimmer reliably, for 38V a 0.5W trimmer will not suffer initially but better not for long term. FAIRCHILD KSA1381/KSC3503 can be found in large stockists, prefer ESTU hfe grade. Its power inefficient to use shunt regs with such constant current over load demand allowances in those voltages, watch your thermal planning and M1,M2 sinking.

[gentlevoice]

Only BJT output version there is for V1 and 1.1, the CCS is still Mosfet. I recommend full Mosfet if looking for 5V and up. 1.1 guide you can find in "SSLV 1.1 builds and fairy tales" thread, post#1

Thanks Salas :-) I'll take a look at it ....

Jesper

[Dr.H]

Originally Posted by Salas

This config should do theoretically. For 75Vin & 38Vout R9 should be 24K, R6 8.8K, C2 50V. For 75Vout R6 can't be a trimmer reliably, for 38V a 0.5W trimmer will not suffer initially but better not for long term. FAIRCHILD KSA1381/KSC3503 can be found in large stockists, prefer ESTU hfe grade. Its power inefficient to use shunt regs with such constant current over load demand allowances in those voltages, watch your thermal planning and M1,M2 sinking.

Thanks Salas, at the moment there is Zener being used for both. Sure this will be much much better!

[Salas]

And much much hotter. What is it for exactly, do you know the load's max demand in mA? This knowledge can save you heat for knowing your CCS setting limits leading to better setting decision.

[johnm]

Originally Posted by Salas

You can't run an Aston Martin on dirty petrol, can you? Its the same with PSU juice. Must be clean. When shunt is high octane also.

Absolutely! It's a turbo-charged beast from hell now

Thanks for getting me yet another step closer to the music

J

[Phisci]

Salas, newbie here. To measure the peak current used, can I insert a 1R resistor between the last smoothing cap and circuit being fed (say DAC) and measure voltage across that? Would that not be an average DC voltage? How would I estimate peak voltage (and hence peak I from V/1R)?

[Salas]

Do that with 1R to know, play full signal, the most DC drop you can achieve with 0dB digital peak program.

[Phisci]

Cheers, will try that.

[Phisci]

More questions if I may: Can I run several loads off 1 shunt reg (for example 74hc74 flip flop as well as a DAC (+5V))?
What about using one transformer with multiple secondaries to power several of the shunt regs?