I have a Denon DAP2500, and while browsing the service manual I noticed that it has a sample-and-hold circuit (despite using two DACs per channel) that I assume is for deglitching.
By comparison, the (older but also more expensive) DAP5500 (also PCM56P, but -K) doesn't have the sample-and-hold but uses a more aggressive and presumably expensive analog filter than the 2500.
My first guess was that this is due to the DAP2500 being a newer implementation, or maybe there is something (the analog filter?) that makes this just a cheaper approach (?). I also haven't dug deeply into the digital filters (both are 4x OS, though).
Was this a common trick to s&h a (supposedly) non-glitchy DAC to relax filter requirements? Or am I overlooking something else that is happening? Some old threads on their CD players of the era (DCD-810) suggest that they also have s&h circuits with dual PCM56Ps.
By comparison, the (older but also more expensive) DAP5500 (also PCM56P, but -K) doesn't have the sample-and-hold but uses a more aggressive and presumably expensive analog filter than the 2500.
My first guess was that this is due to the DAP2500 being a newer implementation, or maybe there is something (the analog filter?) that makes this just a cheaper approach (?). I also haven't dug deeply into the digital filters (both are 4x OS, though).
Was this a common trick to s&h a (supposedly) non-glitchy DAC to relax filter requirements? Or am I overlooking something else that is happening? Some old threads on their CD players of the era (DCD-810) suggest that they also have s&h circuits with dual PCM56Ps.
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Sorry to reply so late...
The DAP2500 does not use any extra logic to achieve higher resolution -- It is just a 16 bit DAC, with PCM56P and a deglitcher.
But, judging by some pictures I found of the DAP5500 analog filter, which must have been very expensive, the deglitcher in the 2500 must provide a significant cost savings and perhaps even some measurable performance advantage.
Just for fun.
Here's the DAP-5500 filter circuit, and the Denon DCD-1500 CD player's analog filter.
The DCD-1500 is from the mid eighties, the next DCD in line was the 1500II which already didn't have the linear phase analog filter.
Here's the DAP-5500 filter circuit, and the Denon DCD-1500 CD player's analog filter.
The DCD-1500 is from the mid eighties, the next DCD in line was the 1500II which already didn't have the linear phase analog filter.
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