The simplistic Salas low voltage shunt regulator - Page 623 - diyAudio
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Old 13th October 2013, 11:31 AM   #6221
Salas is offline Salas  Greece
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Maybe some internals in datasheets show clamp diodes and we can estimate? But they don't mention reverse insertion fault endurance usually. It would be useful info.
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Old 18th October 2013, 02:17 PM   #6222
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Quote:
Originally Posted by Salas View Post
Not 0.1uF only, small super low ESR films in general will interfere with the fixed Zobel termination of the Bib if there is not much inductance in between to really decouple and will cut a lot of phase margin. They have caused oscillation even. We had a couple of practical examples in this thread where they have caused instability that fixed with their removal. Harsher flat sound like when with EMI interference is a clue. Reflektor is more tolerant but its better without too. You can try without any film on the load's rail, short run of 4 wire cabling, or tantalum rail bypass if it has something to really do there. The shunt reg will damp the load's rail differently than a series one, especially on 4 wire connection.
i'm using bib's 1.2V (with D45) and 3.3V (with bjt) for Ackodac, that has 100uF (electrolyt) and 0.1uF (film) as decoupling on all analog and digital supplies. The wirelength from bib to ackodac is about 2 cm.

What would be the best option.
- remove 100uF an all supplies
- remove 100uF AND 0.1 uF on all supplies?
- drop the zobel filter on bib?
- use 47uF electrolyt cap on bib, and remove 100uF an all supplies?

- different meassures for analog and digital?

Is there any other method to meassure what is best - except listening-test and theoretical reasoning?

Peter
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Old 18th October 2013, 02:29 PM   #6223
Salas is offline Salas  Greece
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First you should use the oscilloscope. By looking at the rails in AC coupling input switch mode. If you will see no sine wave like oscillations then the system is OK as it is.
If its not I would remove the very small value capacitors first.
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Old 28th October 2013, 11:11 PM   #6224
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Hi Salas!

I would like to use your design with my KumisaIII headphone amplifier. I'm going to need +-15VDC/230mA.

Which version should I choose?

greetings, JŠnos
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Old 28th October 2013, 11:26 PM   #6225
Salas is offline Salas  Greece
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SSLV1.1 should be enough.
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Old 29th October 2013, 10:12 AM   #6226
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Thanks for the response. Do you know where I can find a good pcb layout for the sslv1.1? I would like to design my own pcb with on board transformer, rectifier diodes etc., and as a newbie it"s a great help to have a layout to rely on.

JŠnos
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Old 25th November 2013, 09:29 PM   #6227
pchw is offline pchw  United States
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Lookie lookie, my first reflector powered up, and a little adjustment at the pot, it was dead on 5V, so happy Will swap out the Bib with this later for a comparision.
Will need a little advise from the expert.
The reflector has been working flawless for 6 months, but when it is compared to my BiB 1.1, I always feel the high is not as crisp. I think I can use some expert advise here. The circuit is based in the a variation of the 5V as in the attachment.

The major changes (as of now) are:
1. The Zobel Cap (C5??) is a 34nf Mica instead of the 0.47uF
2. The 2 x 820uF is replaced by a 2700uF bypassed by a 0.22uf Epcos polypropylene.
3. M2 is IRF610 instead of IRF640.
4. The 2 x 560R are replaced by 1 x 1150R.

Any suggestion to components change to try? The load is no mor ethan 75ma, and the CCS is set to deliver approx 250ma, and the output is 5V.

Thanks!!
Attached Images
File Type: png Reflector-5V.png (26.5 KB, 415 views)
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Old 25th November 2013, 09:33 PM   #6228
Salas is offline Salas  Greece
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M2 has low current gain. Replace with the suggested high gfs ones.
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Old 25th November 2013, 09:37 PM   #6229
pchw is offline pchw  United States
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Wow, that's a supersonic speed response.
Any suggestion to what kind of parameters in the specs to look for and to avoid as well?
I don't have the suggested device but hope I can find some in my bins to use.

Thanks!!
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Old 25th November 2013, 09:47 PM   #6230
Salas is offline Salas  Greece
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The lower the Crss and the higher the gfs the better.
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