- Apr 1, 2014
4) Passive Filtering and Discrete Analogue stage
The analogue stage in the iDSD Pro will be completely discrete, no Op-Amp IC's and in fact the actual discrete design will also not just be Op-Amp made discrete (and often worse than the best integrated ones) but will use something radically different, pure Class A () being among the features. Much of the circuitry draws its inspiration from legendary and exceptionally sounding studio equipment.
Not only that, but the DAC outputs will have a purely passive, CLC (Capacitor-Resistor-Capacitor) based lowpass filter to remove ultrasonic noise. Commonly the DAC outputs are filtered at least in part active. Often active filters struggle with the amount ultrasonic noise and RFI they have to handle and at a few 100kHz they often loose the ability to filter at all.
Not so for the iDSD Pro. Using passive CLC filtering provides the correct filtering out to many Megahertz, so that the following analogue stage is not required to handle ultrasonic noise and RFI outside it's ability to handle.
Hey guys, question for all (and the above quote is related to the iDSD Pro outputs): given these features, would you take this to mean that this would relate to the XLR outputs, as well, leading into, let's say a headphone amp?
I'm showing some of my lack of technical knowledge, being that I'm used to Op-Amps, but I've read a few articles to bolster my knowledge, concerning passive, discrete, amplification, sooooo...
What I'm trying to get at here, if I understand this correctly, if the iDSD Pro runs XLR outs without the use of Op-Amps, then the balanced signal going into my HP amp should not have the colorization intrinsic in most Op-Amp based preamps?
That's kind of been a problem of mine, for a while, even with the iDSD micro, that if I don't go direct, but instead opt for preamp mode, the signal going into my headphone amp is in some way colored by the preamp sound. I'm not getting the straight sound, in other words.
In a perfect world I would like to set my HP amp to unity gain and then control my volume with a transparent preamp. It sounds like this is what iFi is getting at here, or am I off base?