You should have used a variac to gradually power up the amp for at least several hours before connecting it to speakers. This would give the power supply caps time to reform. With the first power cord the caps were still not at full charge. By the time you switched to power cord two the caps were near or at full charge. Nothing to do with the quality of the power cords.
Power cable dilemma
I have to ask the community for an explanation to account for an issue I encountered this past week.
I received a Mark Levinson ML-23.5 amp this past week. I plugged it in with a high end power cord I purchased years ago (because it looked better than the cheap cord that came with the unit. Lol). I switched from an ML-9 so I had certain expectation of the sound. After listening for about 30 minutes, I noticed that the amp did not sound very dynamic. I got up to go feel how hot it was and the heat sinks were barely warm. I turned up the volume and listened for another 15-20 minutes. I got up to check the temperature and the heat sinks were still barely warm. Also, I was playing the amp at volume level 28 on my Cambridge 851N. That is pretty high. The sound was still lifeless. I shut everything down and just sat there, dejected. Was the amp defective? Was it just a bad match? Were my expectations too high? I don’t know what made me try it, but I swapped out the power cord with a plain black cord and powered up the system. Unreal. I was now listening at volume level 22 to the same song, with staggering dynamic impact, at what seemed to be a similar volume. Furthermore, after about 20 minutes, I went up to feel the amp and the heat sinks were very toasty! So the question is: what could have possibly been wrong with the original cord that would result in lower volumes and no heat buildup? It is like it was throttling the current. To me, a cord either connects or it doesn’t. It works or it doesn’t. There should not be an in between. Does anyone have an explanation for this?