no its not a ladder/r2r either afaik, I think (since its not mentioned) that the NXP dac (philips semiconductor is now called NXP) Charles uses is of the same ilk, so not an R-2R either, rather a current source, so the current is divided/switched with active current sources made from transistors, rather than the being divided with resistors (which can result in voltage output). i'm not certain of the model and i'm talking somewhat out of school here, perhaps we could know more if there was more than marketing spin published about the design.....
as such I do not know specifically how the noise shaping works in this Dac X, but it will be dither and noise shaping that will make the output from the dac bearable in the case of the TP, as well as perhaps some form of analogue filter to soften the digital distortion. because it is a fact that if you turn the volume down with a 16bit dac, with 16bit source material you start losing information, so it will depend greatly on the headphones you use with TP, the resolution you get, because you will only be able to comfortably turn the volume up to a certain level, which will be lower with low impedance.
i've linked it before, but
this explains it pretty well. its an ESS document, so ignore that, but it does give you a decent overview. whats important is that the TP uses a 16bit dac and the effect of turning down the volume is explained in te first few pages, it then goes on to show how both analogue and more advanced 32bit dacs and digital volume improves on 16bit dac and digital.
also another term that might need explaining is ENOB (Equivalent Number Of Bits) which describes the dynamic range/Signal to noise ratio in the analogue noise/frequency domain and how that relates to the equivalent amount of information that analogue signal can portray. this is not accurately known without knowing the performance of the amplifier stage in the TP and how well it deals with different volume and different load impedances, which is also all information which is undisclosed with the TP. but having such low supply voltage and low current I dont know how good it could be...
its worth noting that DSD is only 1bit and there are newer technologies coming into play like multibit DSD, which will probably be 4 or 6 bit, so a small number of bits CAN be used to good effect, but it takes a different approach, DSD uses whats called PWM (Pulse width modulation) to describe a musical signal with only 2 states. but we wont go into that here, its not the same thing and cannot be used to explain the enjoyment some get with the TP, that I would rather not try and describe. its not because of being more transparent or detailed....thats for sure. its not having hires capability because despite its label, it cannot really play them, using 24bit files on the TP gains you nothing and just uses more space.
so TBH i'm at a loss, perhaps hes added some nice sounding, pleasantly coloured analogue filter as part of the amplifier or DSP section... only Charles can say unless I had one to dissect and no I dont plan to buy one.
I linked to that one because it was good on the topic of ultrasonics. I take it that he didn't consider a DAC upgrade to an existing player a viable one - only a case-hardened DIYer would attempt it on a DAP. I know I wouldn't - rather I'd change the DAP.
