David Sylvian - Gone to Earth  

I get you are worried about noise in your signal path. That is a valid concern in most audio designs. However, I don't think it's as much of a concern in this particular path as in others closer to your ear. The signal amplification after the internal DAC chip in your DAC box is simply to amplify or attenuate that analog signal to match the required DAC box's line level output voltage, which is typically .3-.4 Volts. If your line level output voltage is much higher than that, you could overload your preamp input and end up with very noisy playback. It's not like it's driving your speakers. From what I've Googled, there's not much of a circuit needed to convert the DAC chip's output signal to a line level output. It looks like it's usually done a simple op amp. There doesn't appear to be a lot of circuit design variations to clean this up. I suppose someone could use a shitty opamp but that would be pretty stupid on their part. To be honest, I would hope that any circuit designer would make sure that the signal coming out of their box, be it a CD player or DAC, had very low noise or they wouldn't be a circuit designer for very long. I personally wouldn't worry too much about it either, as long as you stick with reputable companies and not some cheapie manufacturer like Crosley. Then again, many of my "work friends" over the years have been circuit designers. Sure, I worked with some lazy designers but even they had to make the circuit work as expected or no one would buy the resulting product. I have had to get down into the guts of a lot of these circuits to help these designers debug their circuits when they didn't work as expected. Every single one of them knew their circuits inside and out. When I graduated from college, I tried getting a job in the audio industry but no one was hiring back then. Instead, I stuck with RF products (50 MHz-100 GHz signals) so I worked a little higher in frequency than audio.   I bet I've debugged thousands of RF circuits at this point in my life. Sometimes I miss doing that, but then I remember all the office politics and the shitty commutes and I thank my brother Dan again for making me stuff so much money into my 401K so that I could retire early.