Having seen your technical credentials and extensive hands-on experience with Chord products ...
chord 1,000,000 taps
- Thread starter philiphifi
- Start date
Having seen your technical credentials and extensive hands-on experience with Chord products ...
I wonder if anyone has. It would be nice to see the manufacturer provide proper listening test demonstration of the claimed benefits.
Werner
pfm Member
OK if you define 'brick wall' as 100% passband, 0% stopband, zero-width transition, and zero phase distortion. I.e. sin(x)/x. Any other filter with less suppression leaves some of the images in the output signal, and with more suppression leaves some of the music out.
Actually it is impossible to implement in the analogue domain. Early Japanese CD players used a high-order analogue filter with cut-off at Fs/2, deviating substantially from what the Sampling Theorem ordered. Philips with their x4 oversampling had a fair stab at it, though.
Right, I've read that those early Marantz players used 3rd order filters using the 1540 with it's 4x oversampling, and the reduction in passband distortion compared to much higher order analog filters was substantial, and lead to the appreciation of the benefits of simpler analog circuits, and higher oversampling, as work in the digital domain is superior and essentially free. This of course led to bitstream as the ultimate reduction in output circuit complexity with all the clever stuff moved to the digital side.
davidsrsb
pfm Member
Baseband filtering needed very high order filters, which in turn had poor group delay and had both horrible manufacturing adjustment cost and long term component stability problems.
Upsampling x4 eliminated all of these analogue issues, except that the actual DAC chips were probably not quite as linear at the higher clock
Upsampling x4 eliminated all of these analogue issues, except that the actual DAC chips were probably not quite as linear at the higher clock