I was on the Chinese headphone forums and saw an discussion of a bug in the ES9018 chip. They uploaded an email from ESS to prove their point. I'm not a DIYer so I don't know exactly what they're talking about, and what the actual problem is.
Quote from the forums:
"ESS在2010/01/28有一份DAC scrambling THD issue的application note,是在講利用scramble the volume settings
"On 28th Jan 2010, ESS posted an application note on the issue of DAC scrambling THD, and talked about reducing the problem by scrambling the volume settings, but it does not solve the issue."
According to the forum, John Westlake said this on his own forums:
"I'll never use the ESS9018 again as an integrated DAC solution in our designs its SO FULL OF BUGS. We pull our hair out, its REALLY REALLY Buggy, some issues are more serous then others... ESS should really have re-spun the silicon to resolve the bugs."
The forum also contained a graph posted by another member, with him saying:
所以這個問題無關併不併聯.ESS HQ也很明確說這是他們目前晶片技術上的副作用,他們也在2010發現這個問題所以寫了一份Application Note來解釋這個問題.
"I posted this image explaining this, and do not PM me to ask anymore. Both channels have the same issue, so I only took one channel. The board tested is the demo board provided by ESS, input is SPDIF. Blue color is -35dB input signal, green color is -36dB input signal. Generally, a signal with a difference of only 1dB should have very similar test results. However, from the image below, green is normal, but blue starting from 200Hz to above 20kHz have an unusual bump and 'High-order harmonic distortion'. This problem appears in many places, which is what I mean by abnormal distortion. This problem appears even if ES9018 is only used for one channel only. ESS HQ also clearly stated that this is a side effect of using their chip's technology, and they discovered this problem in 2010, so they wrote an Application Note explaining this...ESS told me that this problem has no solutions."
Can anyone experienced in Head-Fi come out to explain this? Is the ESS9018 still a good chip to use? Thanks!
Edited by Xymordos - 3/14/13 at 6:50am