solderdude
Grand Contributor
1) All the DAC measurements are in our mind misleading. They were measured at a level where the amplifier is clipping. In our view, they should be dismissed completely.
1.1) There has been some debate on how we can allow the RCA pre out to be optimized at 550mV, which actually is a fair question. The reasoning behind this is that we mainly see this as a subwoofer connection. Obviously you can debate wether that is a good or a bad choice.
When the pre amp output is more than 550 mV, the speaker output will be clipping and that will influence the performance of the pre out.
The pre-out on the H95 is taken directly from the power amplifiers input stage. See figure below:
View attachment 168201
When the power amplifier starts clipping, this will reflect in the RCA pre out as well. As such, the RCA pre out can NOT be used as a 2V DAC output. When we measure the DAC performance we connect Audio Precision directly to the output stage of the DAC board. You can of course also measure the DAC on the RCA output, but with a lower setting than 98 and it will include factors from the preamp.
That explanation makes perfect sense.
We can see the 'clipping alike' behavior we see is also seen in the knee at -11dB which not surprisingly calculates to 0.56V.
Indeed, as @KSTR also mentioned, the DAC measurements are not correct and would advice @amirm to either re-measure at 550mV as 0dB or remove the line-out measurements or make a note stating that the line-out is 550mV FSD instead of the usual 2V.
Now... below 560mV the performance isn't great either though and about similar in performance to the cheap Razor USB dongle.
And as you say the line-out with 0,55V is a strange decision. Why not add a simple opamp with say 4x gain and line-out would have complied more to current line-levels instead of 5-pole DIN plug line level values.
Even when using the outs for subs (could have called it sub-out ?) the 2V would still make sense.
Another thing.. why is there NOTHING in the sparse data sheet about the line output and headphone out level/impedance ?
Perhaps in the future create a bit better specifications ? This
Devices look nice.. maybe get your specifications in order as well ?
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