I do not believe all equipment sounds the same unless it meets the criteria I stated. So if a preamp is designed to colorize the sound to seperate itself from the rest (like many high end ones do) then what I said does not stand (In addition it proves that many low cost pre-amps will measure and sound better than high end ones if better sound to you means transparency and letting the original recording through). But If it does meet the criteria I gave it will sound the same as long as the setup is identical. We are assuming the preamp does not have equalization errors, frequency response anomolies (must be flat) or overload problems. If we are talking about an amp it should have high input impedance, low output impedance, no frequency response anomolies, and be at all times operated within its voltage and current capabilities. Think about what I am saying it is nothing special. If two devices have flat frequency response (transparency and no colorization) and distortion less than human hearing they will sound the same. Does that not HAVE to be true? The only way to prove it is to measure the output frequency response or do a BLIND A/B test under controlled conditions. In addition, they must be set to the same dB to within .10, so you need a accurate instrument to validate this (just setting the volume wont do it). The reason is that what we percieve to be better sound is generally more power or volume and humans can differentiate very small changes in volume. So you buy a new amp, stick it in, set it to the same volume (manually) hey better sound. When in fact it was good power reserves.

As for CD players well that the same story as well. Digital audio equipment must meet the preamp qualifications I gave earlier (for analog) and be up to present day standards of D/A conversion to qualify for my statement. Maybe if you got a seriously cheap one with really bad analog circuits and you used the analog output you could hear a difference (due to distortion). And even then, if you used the digital out and used YOUR D/A converter of your pre-amp how can it sound different? Any player up to modern standards should sound the same. How can it not, it is digital information not sound.

Like I said, this is the measurable/engineering point of view. And I know it is not popular. But I feel if something measures the same it sounds the same and all decent modern electronics have such a low noise floor, and flat response that they can not be differentiated by our ears (unless the device was designed to sound different and NOT be transparent). Of course you still have to buy based on features, build quality and power (to avoid clipping and distortion). But in the end, if you want to have better sound, get a good amp with plenty of power (Outlaw makes a couple I can recommend..hehe),good pre-amp (again Outlaw, decent CD player, and spend the large chunk of your money on speakers. You will see that when you visit the exotic sound stores you can NOT hear what the salesperson claims to hear (the famous did you hear that?). I wonder why???