I still haven't got around to putting the clock 2 I've got lying around into my CD53. It's a bit more involved than normal because the clock is the wrong frequency (deliberately...), but at some point I'll do it (once I get that project back on again... moving house and lack of a suitable power supply put it on hold). However, that project involves intercepting the I2S in the player and feeding into a PCM=>PWM amplifier, so differences to the output might be hard to quantify. \r\n\r\nMy comments regarding how worthwhile clocking the CD6000 would be stem from previous experience. I had a Rotel 991, which gained a fair bit when clocked and psued(despite being a pretty low jitter starting point), but then it was walked over as a transport into my superDAC by a stock marantz CD16. With a trichord DOB in the marantz, it's further ahead. So I think it's not worth spending £300 on a Clock 4 and NC psu to put into a sub £300 rrp player which has various other limitations on its performance, especially when considering that the CD16 only cost me £300.