The simplistic Salas low voltage shunt regulator - Page 54 - diyAudio
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Old 17th June 2009, 02:40 AM   #531
jam is offline jam  United States
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Great work Iko................I wonder if you can hear the difference but every little thing helps and the total sum of all the changes is probably quite audible.

I know that attention to detail like this is quite obvious in the implementation of feedback loops in power amps.

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Old 17th June 2009, 03:23 AM   #532
iko is offline iko  Canada
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Haven't had the time to put on the headphone amp to listen carefully, but I don't think it would make so much of a difference to my setup right now, as I'm using it with a phono stage that doesn't benefit much from low output impedance. It should make a difference though in the gainclone that I'm planning to power with a couple of shunts.
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Old 17th June 2009, 03:31 AM   #533
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Can it possibly be used with a Class T amp like Charlize which draws higher current as it is now?
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Old 17th June 2009, 03:38 AM   #534
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Ah, the remote sense system, like the Super Reg "a la" Jung, Didden, ALW, etc.

So, you have left the R8 close to the Q4, and seperated the +ve connection of the J3, ZD (and it's C2) with a "sense wire" connected seperately to the active cct load point, and it makes a noticeable difference, yes?

Then, the gnd (or 0volt) point should also be seperated too - thus the 0v at R6 and Q3 should also have a "remote sense" seperate wire from the active cct load, yes?

As the pcb layout is based on the idea of "star point", this will require a rather different design, methinks.

Could you try this extra 0volt wire idea, Iko?

I remember well the confusion (and some "disbelief") this little thing produced when the Super Reg was first introduced and the patience of many people explaining the idea of "remote sense".
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Old 17th June 2009, 03:40 AM   #535
iko is offline iko  Canada
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I think salas said he knows somebody who's using it with a class-t amp, but I could be wrong. I don't see a reason why it should not work, of course, if the proper provisions would be made for the high power dissipation.
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Old 17th June 2009, 03:46 AM   #536
iko is offline iko  Canada
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Interesting, James. I'm a few years behind, as you can see

I'll look into it then, sure.

Edit: I would leave the star ground as is for now. I'm having a bit of trouble understanding why the ground of the sense should be "moved' to a higher potential. Simulations confirm my suspicion that it would make things worse, but I could be wrong.
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Old 17th June 2009, 04:45 AM   #537
iko is offline iko  Canada
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OK James, I'm convinced now. Here it is.
Attached Images
File Type: png sss1.png (91.0 KB, 995 views)
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Old 17th June 2009, 05:23 AM   #538
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Yes, "floating" the 0volt to the R6 shouldn't matter at all, but loosening the solid gnd point of the Q3 could possibly be a problem. Interesting, eh!

Also, if you look at the J3 current source, would this be better "floating" on the sense wire (a feedback mechanism, as you have tried) or would it be better off tied directly to the Q4 source (no f.back &/or possible stability problems?)
This would, maybe, leave only the ZD (and C2) subject to the sense (feedback) correction - simpler to follow, but perhaps not
correct either!


If it's possible with your setup, could you try this out?

Yeah, I come from awhile back when we built the transformers for sound, valve rectifiers, and used snubbers and such things for noise control, etc - it's quite suprising how much of the "ol' ways" are still useful!
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Old 17th June 2009, 05:42 AM   #539
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Sorry Iko,
I missed your last post

- a "floating driver stage" with a fixed reference (the opposite to my last post) with the "sense" +ve equal to the gnd wire - those external wires are giving the J3, Q3 the appearance of a differential f.back system, eh!

Stabilty, maybe? Although this Reg with it's heavy Ishunt is so solid, I doubt it'll become a problem.

Thank you for providing so much thought, time and effort for this.
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Old 17th June 2009, 08:52 AM   #540
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Hi Salas, with now 8000uF of filtering before V1 shunt regulator, my Le Pacific RIAA is sounding good to me with very low noise floor working together with a Coral mc transformer. Components used so far has been all generic with nothing exotic.

I only have 1.0uF coupling capacitor on the RIAA and not sure if changing that to 2.2uF will have any benefit to the sound.
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