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Old 12th July 2013, 09:50 AM   #21
AndrewT is offline AndrewT  Scotland
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Trans,
thanks for the post18 link. I had missed that.

Your redraw of the Jung Shunt Reg omits the sensing "Bridge". This is important for good regulation. The remote sensing terminals are also good for regulation at the load.

For those reading the post go to the Jung link to see correct implementation.
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Old 12th July 2013, 12:14 PM   #22
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I simmed WJ's "shunt" -- it has the same issues as the Salas -- higher harmonics.
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Old 12th July 2013, 02:15 PM   #23
iko is offline iko  Canada
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The shunt reg can safely pass another 10mA to ground continuously, think of it as reserve current ready to be given to your load when it needs it. So you can set it up for a total current draw of about 20mA. It will have really low output impedance, and outstanding psrr. Maybe it's over the top for your need, but you're bound to learn some good things building it. Then again, you can just use an LM chip and call it a day. You might never be able to hear a difference, because the regulator might not be the weakest link in your chain. They're all suggestions, and you can learn a lot by implementing two or three and comparing them. Beauty of diy sky's the limit. Well, and what the wife permits.
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Old 12th July 2013, 02:37 PM   #24
iko is offline iko  Canada
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Quote:
Originally Posted by jackinnj View Post
I simmed WJ's "shunt" -- it has the same issues as the Salas -- higher harmonics.
I'm curious what you mean by higher harmonics. I'm not challenging the claim, just want to know what you mean.
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Old 12th July 2013, 02:41 PM   #25
JMFahey is offline JMFahey  Argentina
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For such a low current a Zener is more than enough.
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Old 12th July 2013, 10:25 PM   #26
tjencks is offline tjencks  United States
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Thanks all for your continue comments and suggestions. I'll be ordering Linear Audio vol. 4 to check out the regulator bake off. I found a few of the performance plots online at tech-diy.com or something like that. Looks like the Jung performed the best, though obviously I haven't yet read about the listening folks did.

Yes this is likely way overkill for my application. I probably would be just fine without a regulator at all. Or was also thinking about an a basic LC arrangement as that is supposed to prove reasonable regulation as well, "if target inductance is achieved.".

But I think I'm finally settling on an attempt at implementing the Jung design just because. Though I'm interested if someone can describe the benefit of running the Jung as a shunt regulator instead of how its is normally described and configured?

Is it that my idle current is to low to achieve the best of what the regulator has to offer?

-TJ
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Old 12th July 2013, 10:44 PM   #27
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Quote:
Originally Posted by tjencks View Post
I'm interested if someone can describe the benefit of running the Jung as a shunt regulator instead of how its is normally described and configured?
Jung himself attempts to do so, on page 5 of the audioXpress article linked in post #18. For example,
... made a valuable point related to power supplies, which is that a shunt-type regulator localizes audio dynamic currents. Going further on this theme, in contrast, a series-type regulator returns dynamic audio currents all the way back to the raw DC supply! The latter type uses a long-series loop, as opposed to the short loop of a shunt. For audio, there are some profound implications to these differences ...

... In stark contrast (any) shunt-type regulator provides inherent isolation between the audio stages and a dirty raw supply, by virtue of a high-z series input leg consisting of either a current source (or a choke), and a shunt regulator stage that regulates its own terminal voltage.
and many paragraphs in between
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Old 13th July 2013, 01:14 AM   #28
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Quote:
Originally Posted by iko View Post
I'm curious what you mean by higher harmonics. I'm not challenging the claim, just want to know what you mean.
A couple months after the article was published one correspondent suggested that we take a look at the harmonics if a 1kHz (for example)current was impressed upon the power supply rail. Mirabile dictu, the rankings in the listening test seemed to correlate better with the harmonic content than PSRR, noise or Zout.

Anyone can do it with a decent sound card and fft program.

My guess is that the error amplifier in the commonly seen shunt designs are less than perfect...
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Old 13th July 2013, 12:55 PM   #29
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With load of just 8 mA you can place a 22 - 100 Ohm resitor along with a 330 - 1000 uF capacitor to form a RC low - pass filter on the output, which will virtually eliminate any noise.
Like this :

|''''''''''''''''''''''|
| 7815 |------[|100R|]-------------------OUT
|.............| __|__
| _____ 1000uF
| |
| |
GND GND
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Old 13th July 2013, 06:22 PM   #30
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Noise isn't as important is PSRR and Z-out. Putting a series resistor in isn't helpful.
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