You all are a great resource — thank you so much!
Downside to R2R Ladder DACs?
A sales person I generally trust told me to steer clear of used R2R DACs, since their reliance on high precision resistors causes them to sound best when new, and degrade fairly quickly. It seems reasonable; have others had any experience with this?
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- 33 posts total
I don’t know much about R2R Dacs of 10 years ago,but when I see the inside of a Denafrips R2R Dac with over 400 capacitors I wonder more about the sound impact of any number of those caps going bad over timeIt’s very good for power supplies, as many small cap have far lower ESR (google it) than one or two big caps of the same uF. The energy release for transients is far quicker with lower ESR. The same now is happening for power supplies in poweramps of the higher end ones. Look at these in my 2 x amps, if you look close there are 2 cap stacks per channel https://ibb.co/cQXGW1F https://ibb.co/2WbJc5k https://ibb.co/h9b4T0X Cheers George |
George, this is very true - two power supply caps in parallel have smaller ESR, but they also have smaller inductance, often horrible for very large caps. In addition few smaller caps instead of one large cap allows for better packaging (more efficient use of space). Point made by hrabieh is very good - DAC is not only D/A converter but far more. There are many DACs based on the same D/A chip that sound differently and have different reliability. |
George, this is very true - two power supply caps in parallel have smaller ESR,And it’s great we can access cheap ones from our little Chinese buddies who make them complete ready to go at what just our parts cost would be. Many more variation on this theme in ebay voltage and capacitance. https://www.ebay.com.au/itm/DIY-kit-62cps-Nichicon-330uf-100V-Array-Power-supply-kit-for-Power-amp-D... Cheers George |
R2R DACs are dependent on the accuracy of the resistors. Therefore if a particular design has a long term problem with one or more resistor values changing (absolutely or relative to the other resistors), then the DAC will be degraded. I suspect that unless the degradation is gross, most people would not hear the difference with normal music at normal listening levels. So saying "my 20 year old R2R DAC sounds great" is probably not a valid test! However, the degradation would be measurable and that would be a valid test. If this was a common, significant problem, I would expect there to be a lot of published engineering articles demonstrating it, but I've not stumbled on anything yet. |
- 33 posts total