Skeleton Dac Resistor Values?
Dec 26, 2013 at 4:57 PM Thread Starter Post #1 of 4

Science Guy

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Hi, I plan on building a skeleton dac, and I was wondering how important are the smd resistor/cap values?  For instance, the BOM asks for a 20 pf cap, but would a 22pf cap work in its place?  What about resistors, would a 100 or 120 ohm resistor work in place of the 110 ohm resistor in the BOM?  I am not sure how essential these values are.  As long as I am within +-10% do you think I will be okay?  Please help!
 
By the way, here is the link to the BOM (PDF):
 
http://www.diyforums.org/SkeletonDAC/bom/SkeletonDAC-BOM.pdf
 
Dec 26, 2013 at 6:05 PM Post #2 of 4
  Hi, I plan on building a skeleton dac, and I was wondering how important are the smd resistor/cap values?  For instance, the BOM asks for a 20 pf cap, but would a 22pf cap work in its place?  What about resistors, would a 100 or 120 ohm resistor work in place of the 110 ohm resistor in the BOM?  I am not sure how essential these values are.  As long as I am within +-10% do you think I will be okay?  Please help!
 
By the way, here is the link to the BOM (PDF):
 
http://www.diyforums.org/SkeletonDAC/bom/SkeletonDAC-BOM.pdf


22pf cap - yes.
100 or 120 ohm resistor - I assume you mean R1.  R1 is only used for the transformer option to provide SPDIF.  I doubt very seriously that 100 or 120 is going to affect that.
 
Dec 26, 2013 at 8:36 PM Post #4 of 4
  Ah okay thanks, that really helps.  One last thing, does the value of r9/r13 matter that much?  All I have are 220k resistors, although I can order some 200k if needed.

I'm not sure why you're asking about the combination of R9 and R13.  The correct "pairs" to provide identical stereo channels are R11 & R13, then R9 & R12.  You didn't ask anything about R11 and R12, which must be the same as R13 and R9, respectively.
 
It's not a big deal if R13 is 200K instead of 220K.  However, it's a huge deal if R9 is 200K.  R9 and R12 should be 16R.  That's a monster difference from 220K.
 
Bottom line, these resistors you keep asking about are literally pennies ... we're talking either 8 cents or 16 cents.  I realize that there are shipping costs counted for this stuff, but geez ... if you need several parts - no offense, but try to suck it up and do what's best.  No offense, but the whole dadgum kit is only $22. 
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