Paralleling up DAC chips

5th element · 17th July 2004, 03:47 PM

Is this quite a simple thing to do?

Do you just wire up two DAC chips in the same way and then connect the outputs together and reduce the gain in the I/V stage to account for the larger output current?

If this is the case then could I just place another DAC chip on top of the first one? With the SSOP adaptors ive got I think you can just piggy back them on top of each other, so it would be quite simple to add on another chip.

Cheers for any input Matt

5th element · 17th July 2004, 06:12 PM

Ill just add, is it actually worth it?

pinkmouse · 17th July 2004, 06:52 PM

What is the point?

This isn't a flame, just curious...

jewilson · 17th July 2004, 07:21 PM

I cant see how this is worth doing. Linearly can be affected when the lower order bit from different DAC turn on when at different times. This also can affect the input impedances of the part. One part could current hog on another. Voltage references in the DAC can be affected implementation and degraded. You can end up with more noise and less dynamic range.

ThorstenL · 17th July 2004, 07:37 PM

Konnichiwa,

Quote:

Originally posted by jewilson
I cant see how this is worth doing.

Linearly can be affected when the lower order bit from different DAC turn on when at different times. This also can affect the input impedances of the part. One part could current hog on another. Voltage references in the DAC can be affected implementation and degraded. You can end up with more noise and less dynamic range.

Well, it seems the Engineers at BB/TI do not share your sentiments. Here some notes from their "Theory of operation" section:

"Superior performance and sound quality are produced by
combining the parallel connection of 4 DACs per channel.
This parallel connection technique produces very low THD+N
performance (up to –100dB) and wide dynamic range (up
to 112dB)."

EVM-1702 PCM-1072 EVALUATION MODULE Manual

With all due respect, you seem to have a very limited understanding of converters and how they work, and what important in their design and implementation.

Sayonara

jewilson · 17th July 2004, 07:51 PM

Konnichiwa,

If your in to such a dumb concept you should build the thing but use those TDA1541 :

Know you proved it time and time again that your the one with the limited understanding, but I understand. You still have you head in place where the light does not shine.

Sayonara, your self

stef1777 · 17th July 2004, 07:56 PM

We have this for computers. Why not for audio !

jewilson · 17th July 2004, 08:03 PM

stef1777

If that works for you, cool.

pinkmouse · 17th July 2004, 08:08 PM

Jim, Thorsten, knock off the personal stuff now please.

stef1777 · 17th July 2004, 08:10 PM

Sorry, that's not me. I forgot to place the link.

http://www.dddac.de/ma_dac21.htm

I found this projet very fine. Like an old tube amp... What will apen, if we use 256 chips!!!

17th July 2004, 03:47 PM	#1
5th element diyAudio Member Join Date: Oct 2002 Location: England	Paralleling up DAC chips Is this quite a simple thing to do? Do you just wire up two DAC chips in the same way and then connect the outputs together and reduce the gain in the I/V stage to account for the larger output current? If this is the case then could I just place another DAC chip on top of the first one? With the SSOP adaptors ive got I think you can just piggy back them on top of each other, so it would be quite simple to add on another chip. Cheers for any input Matt __________________ What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Droggon Attack!

17th July 2004, 06:12 PM	#2
5th element diyAudio Member Join Date: Oct 2002 Location: England	Ill just add, is it actually worth it? __________________ What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Droggon Attack!

17th July 2004, 06:52 PM	#3
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	What is the point? This isn't a flame, just curious... __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

17th July 2004, 07:21 PM	#4
jewilson diyAudio Member Join Date: May 2002 Location: Plano , TX	I cant see how this is worth doing. Linearly can be affected when the lower order bit from different DAC turn on when at different times. This also can affect the input impedances of the part. One part could current hog on another. Voltage references in the DAC can be affected implementation and degraded. You can end up with more noise and less dynamic range. __________________ Jim W.

17th July 2004, 07:51 PM	#6
jewilson diyAudio Member Join Date: May 2002 Location: Plano , TX	Konnichiwa, If your in to such a dumb concept you should build the thing but use those TDA1541 : Know you proved it time and time again that your the one with the limited understanding, but I understand. You still have you head in place where the light does not shine. Sayonara, your self __________________ Jim W.


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17th July 2004, 07:56 PM	#7
stef1777 diyAudio Member Join Date: Jun 2004 Location: Paris	We have this for computers. Why not for audio !

17th July 2004, 08:03 PM	#8
jewilson diyAudio Member Join Date: May 2002 Location: Plano , TX	stef1777 If that works for you, cool. __________________ Jim W.

17th July 2004, 08:08 PM	#9
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	Jim, Thorsten, knock off the personal stuff now please. __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

17th July 2004, 08:10 PM	#10
stef1777 diyAudio Member Join Date: Jun 2004 Location: Paris	Sorry, that's not me. I forgot to place the link. http://www.dddac.de/ma_dac21.htm I found this projet very fine. Like an old tube amp... What will apen, if we use 256 chips!!!

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