Upsampling DACS: Take the Pepsi Challenge

Carl, in your opinion, what DACs have well-designed analog circuitry?

I've not analized a lot of them, or taken them apart. I only know that you should look at the analog line level output section seriously, and that a compromised one usually bespeaks a philosophy based on compromise.

I would like to second Kweifi. I just bought a Dodson with the 24/96 upsampling upgrade. I'm using my SCD-1 as a transport. The Dodson has taken a very good- sounding CDP and given it an expanded sounstage,greater detail and a "sparkle" that I now see was missing. All for $2500 (used). David

Perhaps someone on this thread can clear something up for me? I asked the question before on Audiogon: what are the differences between upsampling and oversampling? Carl, you seem to be one of many fans of the improvement wrought by upsampling. Can you explain the difference or are there differences? My understanding is that upsampling and oversampling are basically the same. By upsampling/oversampling the digital filtering can be more aggressive (outside the audio range), leaving only a gentle analog filter before output. Is this basically correct? Upsampling/Oversampling can't actually create information; the process can only allow more accurate retrieval of what is contained in the 16/44.1 signal. Right? As for oversampling, all delta/sigma (1 bit) type DACS must use oversampling. Are the new 24/96 DACS mostly delta/sigma types or are they ladder DACS? Don't mean to divert attention from the thread topic, but the recent attention to upsampling has me wondering if my understanding of the process is correct. Did mfg's just get better at implementing oversampling techniques to get better sound and needed new marketing jargon to draw interest? Thanks!

Greysquirrel; I'm no expert here, and I've had some of the same questions that you do. From reading, I've learned that upsampling and over-sampling are not the same thing. Upsampling adds dither, ie it interpolates between digital bits and then adds "sound" based on an upsampling algorithm via a DSP chip. This serves to make the digital data stream more continuous, ie more analog like. Analog meaning a continuous sound stream as opposed to the bit stream of digital output. Over sampling does not add dither or do any interpolating. Maybe Carl can help us out from here. Cheers. Craig.