The simplistic Salas low voltage shunt regulator

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#62
Post him, some may build this or something really noise critical and they may want to splash out. To tell you the truth, I haven't had any noise problems with 20-36V shunts and normal Zener used on MC phono stages, but it can always reveal better? I guess so.
 
#63
Its Avnet, they stock most microsemi components, at 12v and higher I wouldnt be worried with zener noise, bound to be better than leds but Ive never tested anything beyond 18volts. Below 12v the leds are safest bet.

Ive wondered about tl431, anyone ever test this part for noise??
 
#68
No, I can't spot anything else right now. But I must have seen one or two more comments about better than TL431 in the course of the years. Lets see what we can summarize from what we gathered up to now:
It seems that building with 12V or bigger Zeners and adjusting with Leds can be a short good Vref string of adequate noise for 12-40V shunts. 3.9V-4.7V Zeners and Leds look OK for below 12V. Avoid 5.6V-8.2V normal Zeners. Special tempco parts are nice if available.
All seem to fall in a logical picture. Haven't used low Zeners, haven't had problems.😀
 
#69
No noise regulator...
 

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#72
That reg shown is just my regulator but with TL431 Vref. Its obvious. And I just call it ''Simplistic Low Voltage Shunt''. It has been reported good enough by many who made it with a Zener. Both for practical noise with Riaa or other audio, and subjective sound. Now why with just some different values and another Vref can be called ''No Noise'' it just escapes me.
 

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#74
Me I got it. But I have to clear things for people that may have not followed either the reg story or our individual styles.😎 Remember that people will bump on threads in the years to come even.
As I wrote above, what is really needed is a nice PCB design. Vref options are easy to include too. I think if using a TL431, Vout variability is a great add on.

Anybody good in PCB?
 
#78
As a bandgap device it owes to be noisier than LEDs or avalance Zeners people explained in that noise thread I linked. Its good thing is temperature stability. Also low impedance, being a shunt device. That helps PSRR. Plus its variable. My idea was to use a single Zener (above 12V I have only made or seen made, except JWB's 9V one that used a low quiet Zener (away from bad transition zone) plus 3 smt LEDs.). He had to, since he would be bang on worse Zener choice else. To help the low impedance and PSRR thing I used a low pinch off IDSS CCS to be able to work right under Vbe margin, for the rather high voltage/impedance Zeners. In practice it worked fine. And its capacitor bypassed.
 
#79
ikoflexer said:
I'll try to get a few 1n406x zeners and compare their noise with 1n47xx zeners, just for fun, unless somebody's done it already. Thanks for the tip.

Edit: never mind, I can't find these at digikey, mouser, newark, jameco, at any price.
Click to expand...

At 4 Star I see 1N406x by the boatload.
 
#80
Salas said:


At 4 Star I see 1N406x by the boatload.
Click to expand...

Yes, they require one to ask for a quote. It doesn't look like the kind of place where you just buy a few parts.

Now, IMHO, the probable benefit is not great enough compared to the effort of getting these parts. I'll pass. Whoever has them handy should compare against a regular 1n47xx zeners or anything else that fancies them.

There will be a few challenges yet to overcome in building a regulator whose weakest link is just the voltage reference. We should be happy to get to that point. Are we there already?
 
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