TL 431 regulator question

JC951t · 5th March 2008, 06:19 AM

Hi All,
Need some advice. Aside from low noise, how does the
TL431 sound with pre- regulation when used in a dac ?
Sorry, I know this is subjective but would like to hear
your opinions especially when applied to the TDA1541a
dac.

Thanks to all

philpoole · 5th March 2008, 06:36 AM

Well, my first 1541 DAC used single, 78xx based regulation, and it didn't sound as good as my second DAC, dual regulated lm3x7 followed by TL431.
There may well be better out there, and I haven't measured performance, but it does work well.

JC951t · 6th March 2008, 10:10 AM

Hi,

Thanks for sharing your experience

AndrewT · 6th March 2008, 10:26 AM

Hi,
the TL431 is a shunt regulator.
What limits the shunt current if the preceding regulator is a series type?

philpoole · 7th March 2008, 09:22 AM

Hi AndrewT,

If I understand the question correctly, I use a resistance to limit the current before the TL431. I think I use about 100R. Seems to work okay.

Is that what you mean?
Cheers,
Phil

AndrewT · 7th March 2008, 09:41 AM

Quote:

Originally posted by philpoole
I use a resistance to limit the current before the TL431. I think I use about 100R. Seems to work okay.

Is that what you mean?

yes, a resistor will do just fine.
Alternatively, set up the LM317 as a current source to replace both the pre-regulator and the resistor.

philpoole · 7th March 2008, 03:12 PM

Unfortunately, the pre-regulator feeds other circuits, so using it as a current source isn't really an option.

Is the 317 a good current source?

JC951t · 7th March 2008, 04:48 PM

Hi Philpoole,

Actually I'm toying with that idea but using LT1085
& LT1033 as current source to power the 24 TL431.
Planning to built EC Design DI8M dac.

martin clark · 7th March 2008, 06:47 PM

Quote:

Is the 317 a good current source?

Actually it appears, really quite good: and if you cascode two, they perform superbly well. See for yourself in Walt Jung's two 'Sources 101' papers on current-sources here:

http://waltjung.org/Late_Articles.html

As usual, excellent reading!

ridwans · 31st March 2008, 09:01 AM

Hallo.
i want to ask anyone whose know
how to calculate R
(R1,R2,R3 /R1A,R2A,R2B) value of combination Reg LM317/337 and TL 341

i plant to use for reg +15 -15 output current 300Ma.
input volate +- 20V dc
output 15V
output current 300Ma
this the schematic.

please heelp anyone.
thx

5th March 2008, 06:19 AM	#1
JC951t diyAudio Member Join Date: Sep 2006	TL 431 regulator question Hi All, Need some advice. Aside from low noise, how does the TL431 sound with pre- regulation when used in a dac ? Sorry, I know this is subjective but would like to hear your opinions especially when applied to the TDA1541a dac. Thanks to all

6th March 2008, 10:26 AM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, the TL431 is a shunt regulator. What limits the shunt current if the preceding regulator is a series type? __________________ regards Andrew T.

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5th March 2008, 06:36 AM	#2
philpoole diyAudio Member Join Date: Oct 2004	Well, my first 1541 DAC used single, 78xx based regulation, and it didn't sound as good as my second DAC, dual regulated lm3x7 followed by TL431. There may well be better out there, and I haven't measured performance, but it does work well.

6th March 2008, 10:10 AM	#3
JC951t diyAudio Member Join Date: Sep 2006	Hi, Thanks for sharing your experience

7th March 2008, 09:22 AM	#5
philpoole diyAudio Member Join Date: Oct 2004	Hi AndrewT, If I understand the question correctly, I use a resistance to limit the current before the TL431. I think I use about 100R. Seems to work okay. Is that what you mean? Cheers, Phil

7th March 2008, 03:12 PM	#7
philpoole diyAudio Member Join Date: Oct 2004	Unfortunately, the pre-regulator feeds other circuits, so using it as a current source isn't really an option. Is the 317 a good current source?

7th March 2008, 04:48 PM	#8
JC951t diyAudio Member Join Date: Sep 2006	Hi Philpoole, Actually I'm toying with that idea but using LT1085 & LT1033 as current source to power the 24 TL431. Planning to built EC Design DI8M dac.

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