This Friday I took ownership of some new audio equipment. On the very same day I put to use three new pieces of equipment in my "main" listening room downstairs. * RCA Interconnects (from DAC to preamplifier) * Monoblock amplifiers * preamplifier unit Comparing the "old" stereo to "new" is therefore difficult. Where do the changes in sound belong? So many things are "new." And when can I honestly begin listening to discern the differences? With so many folks talking about burn-in of components, from the cables to the amplifier, what's a proper burn-in time? I frequently come across two figures when I am reading about burn-in. Take a typical review. To wit: Before listening, I let the equipment burn-in for xx *hours, and then I wanted to see what these guys could do..." Well, I hooked everything up. The two new components for me were the cables. I've read that cables can take 100 hours to burn-in. In that case, we're not there yet. And to burn-in, per se, it means that electricity is going through them. I don't recommend routing current, but instead, pushing audio through them. Follow the arrows, too, there's a one-way path. I have no idea why. In fact, I suspect when getting cables, the direction doesn't matter. It's just over continued use, you should follow one direction. I could be completely wrong. But I'm a good boy, and follow the direction of the arrows on the cables. Amplifiers? 30 minimum. 40 hours seems to be a better consensus, but then again, I've also seens 60 and 80 hours. And for tubes, well, that's another ball game. Since plugging in stuff Friday afternoon, and now listening Monday morning before work, there are definitely some changes in what I've been hearing. First-impressions, no burn-in. * When things are powered up, with no music, I hear dead silence. Turn up the volume in the past, and you could hear "noise" in the background. Nice. * More bass. Bloomy, too loud bass. * Laid-back. Middle-section seemed "pushed in," if we were listening to a graph. * Much darker sound. * A softer, smoother sound... but so much so it wasn't desirable. Where had the "crisp" digital sound of my Rotel Integrated Amp gone? Next, what kind of data do you send the system for burn in? I know they make special CDs for this purpose, invariably the question should be asked: variety? Loud symphonic stuff? Will one type of music throughout only "tune" the system for that? I read that someone elsewhere in an audio forum asked whether you needed the whole system on? In other words, did you need to hear the stereo for burn-in to take place. Yes. But then another question of mine was unanswered: Does it matter at what volume we do the burn-in? If I'm running this all day and night, and I want to sleep, it cannot be too loud. I raised the volume in the day, then, and turned it down at night. First night, it got a dose of Baroque orchestral and chamber music. Second night, it got symphonic music by Tan Dun. Third night, it got the night off. And so here we are today. Impressions with some burn-in, approaching 35 hours (around or about, maybe 40): * Still quiet when turned-on * Z-axis depth of sound. I had always heard what I term "x axis" in the so-called sound-stage. Now I hear z-axis (front/back). * much more bass. It's now a bit more controlled. After more burn-in, I may tame it with the port plugs for my speakers. * Warmer sound (in a very pleasant way), more "liquid" sound... musical? mellow... that's the right word. If the sound before on my old equipment was digital, this is a little smoother and far easier on the ears. Now, I'm getting more music. Never would have imagined this quality change before. * More power. Going from 60 to 100 watts... more power. After some more burn-in, testing, and adjustment, I'll publish more details on the new system.