Peter,
Cant you set the output on the DVD Recorder to 44.1Khz? CD is recorded as a 44.1Khz 16bit format, so if your DVD Recorder is shifting it to 48khz it could well be degrading the sound quality. How many digital inputs does your denon have, If it has digital in for a CD transport that might be worth trying, alternativly you could use an analog input and use something like a Marantz CD63, a real classic player with loads of modding potential, which even in its lowest form will likely far outperform your DVD recorder's ability to play CD. It even has a digital output so you can choose to use its DAC's or keep in the digital domain and allow the processors dacs to do the dirty work. (try both and let your ears decide)
While im sure that a cheap (£200ish) AV amp can probably be outperformed in stereo by even the most budget 2 channel amp, there does seem to be a lot of hate for AV gear in general.
But its just not true, I used to have an Audiolab 8000Q preamp, and 8000DAC/8000CDM combo, with 8000M Monoblocks, made lovely music from my CD collection, but I wanted to move into the AV scene properly (All Black UK built versions not IAG silver chineese ones).
So I bought a Tag AV32R, and used that instead of the 8000Q/DAC. So im just using the 8000CDM, and the 8000M's.
Anyway to be totally frank, the musical performance of the AV32R is just astonishing, far better than the 8000Q/DAC . Now I asmit that I dont have the analog bypass, so the Tape/Aux/VCR inputs are all run into a ADC and transfered to the digital domain, but A) I dont actually have any analog sources anymore, and B even when I did have a Cassette deck attached the AV32R still sounded on a par with the 8000Q on the analog side.
Now im pure digital (DVD/Sky+/PC/CD/DVDR) I dont even care about the analog inputs.
But its not just the high end gear that can sound fantastic, my brother has a Yamaha DSP cant remember the exact model, but its Dolby Digital+DTS, with built in amps for surround and centre speaker, but uses an external poweramp for the front L/R speakers. Combined with an Arcam Alpha 9p it makes a quite acceptable Pre-Amp. Sure not as good as the Tag/Audiolab setup I have, but its certainly foot tappingly good.