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Old 19th March 2013, 09:43 AM   #2141
borges is offline borges  Norway
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Didn't mean to intimidate anyone!

I'm happy to share my layout knowledge. Plus, there are so many ways to do things. Perhaps you belong to the figurative 4-layer school while I'm more of a 2-layer impressionist :-)

And if you buy into what Ott writes we have the same starting point.

BÝrge
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Old 19th March 2013, 12:02 PM   #2142
cviller is offline cviller  Denmark
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Now that we are in the knowledge sharing mood, any thoughts on using TL431 shunts as shunts for the supplies? I have seen onoclocks interesting studies of the using the TL431 in a series regulator, but on diyaudio's analog forums, shunt regulators seem to have more street-credit.

In the attached schem, I have included the option for a npn SOT-23 device in cases where more current needs to be shunted.
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Old 19th March 2013, 06:55 PM   #2143
davada is offline davada  Canada
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I finally got my camera working.

These really belong over in the oscillator thread but since I mentioned here...
It is mixed signal though.

These are development boards. I panelized them to save setup charges.
There is one big booboo, see if you can find it. These are from Make PCB in China. I'm not 100% satisfied but these will do. They seem to have trouble getting the holes centered with the pads.

Cheers,
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Old 19th March 2013, 07:06 PM   #2144
davada is offline davada  Canada
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Quote:
Originally Posted by borges View Post
Didn't mean to intimidate anyone!

I'm happy to share my layout knowledge. Plus, there are so many ways to do things. Perhaps you belong to the figurative 4-layer school while I'm more of a 2-layer impressionist :-)

And if you buy into what Ott writes we have the same starting point.

BÝrge
When something just makes sense it's difficult to ignore.
What Ott writes just.....

Cheers,
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Old 19th March 2013, 08:11 PM   #2145
cviller is offline cviller  Denmark
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I have used Make PCB a lot, and you are right that putting the holes in the middle is not their strongest skill. They also have the most hilarious order status system, but very reasonable priced.

Why do your two layout panels share the same gnd plane? Isn't that taking Ott's points too far?
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Old 19th March 2013, 08:18 PM   #2146
1audio is offline 1audio  United States
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Quote:
Originally Posted by cviller View Post
Now that we are in the knowledge sharing mood, any thoughts on using TL431 shunts as shunts for the supplies? I have seen onoclocks interesting studies of the using the TL431 in a series regulator, but on diyaudio's analog forums, shunt regulators seem to have more street-credit.

In the attached schem, I have included the option for a npn SOT-23 device in cases where more current needs to be shunted.
There is nothing intrinsically better about a shunt regulator. The single clear benefit is unambiguous clear indication of where they are connected. Audiophile cred often has no basis in reality and fails miserably when really put to test.

For a USB powered device the lack of efficiency is a real issue.

The TL431 is a great device but its not very low noise. The circuit I posted early in this thread is about as low noise as is possible (1 nV/rt Hz) with an active regulator and optimized for oscillators. It also has much higher line noise rejection than a shunt regulator, really important for oscillators.

I have a variation that is a shunt regulator, attached.
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Old 19th March 2013, 08:38 PM   #2147
cviller is offline cviller  Denmark
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Quote:
Originally Posted by 1audio View Post
There is nothing intrinsically better about a shunt regulator. The single clear benefit is unambiguous clear indication of where they are connected. Audiophile cred often has no basis in reality and fails miserably when really put to test.

For a USB powered device the lack of efficiency is a real issue.

The TL431 is a great device but its not very low noise. The circuit I posted early in this thread is about as low noise as is possible (1 nV/rt Hz) with an active regulator and optimized for oscillators. It also has much higher line noise rejection than a shunt regulator, really important for oscillators.

I have a variation that is a shunt regulator, attached.
Thanks for your input. I am just toying around with different ideas, but ADP151 being the baseline it seems like there are many good options out there. I believe I have found your other regulator here: Open-source USB interface: Audio Widget - is LT1431 better than Onsemi TL431?

BTW: You are right about the Audiophiles. One of the best one I have heard so far is about the importance of which way you place resistors - can't remember if tolerance band needs to be in or against the direction of the signal. But not to worry, you can hear the difference - especially if you have a high end fuse in your circuit.

EDIT: And regarding USB, I plan to use another supply, so that is not really a concern for me.

Last edited by cviller; 19th March 2013 at 08:44 PM.
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Old 19th March 2013, 11:55 PM   #2148
1audio is offline 1audio  United States
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The TL431 and clones are interchangeable in the design. They are used as a "DC servo" to stabilize the output voltage. They are decoupled fr0m the regulation stage with the RC to the base of the follower transistor.
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Old 20th March 2013, 12:17 AM   #2149
davada is offline davada  Canada
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Quote:
Originally Posted by cviller View Post
I have used Make PCB a lot, and you are right that putting the holes in the middle is not their strongest skill. They also have the most hilarious order status system, but very reasonable priced.

Why do your two layout panels share the same gnd plane? Isn't that taking Ott's points too far?
Because they are two boards. I.m cutting them down the middle.
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Old 20th March 2013, 05:27 AM   #2150
davada is offline davada  Canada
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Quote:
Originally Posted by 1audio View Post
There is nothing intrinsically better about a shunt regulator. The single clear benefit is unambiguous clear indication of where they are connected. Audiophile cred often has no basis in reality and fails miserably when really put to test.

For a USB powered device the lack of efficiency is a real issue.

The TL431 is a great device but its not very low noise. The circuit I posted early in this thread is about as low noise as is possible (1 nV/rt Hz) with an active regulator and optimized for oscillators. It also has much higher line noise rejection than a shunt regulator, really important for oscillators.

I have a variation that is a shunt regulator, attached.
This is very impressive. Is there a way of improving the efficiency.
With no load it's drawing 218mA.
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