A posting by @Vw Darren on the Audiophonics TDA1387 ‘ladder’ DAC led me to look at the device and wonder; if the sound is good with a TCXO (temperature-controlled crystal oscillator) that’s good to 5ppm, would it sound better with a TCXO with an error rate of only 1ppm? Looking at the cost of such things (Mouser suggest a 50MHz 1ppm TCXO is £50), I appreciate that this would make a product uneconomical but for a home-brew idea it might be interesting, but only if the TCXO actually makes a big difference. So there’s the question; would that sort of accuracy increase result in an audible improvement?