Sorry to bust your bubble timind, but without trying a better power cord you likely don't even know how that amp REALLY sounds
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Dude, we aren't talking about tubifying it, swapping out parts or modding it. We are ONLY talking about plugging it in (ala with a BETTER plug). Good luck with your amp 
I just spent 2 hours listening through the amp pictured, and I know exactly how this amp "really" sounds. It sounds just the way I want it to sound.

I have used, and still do use upgraded power cords. I don't believe they have any effect on the sound of what ever they're plugged into.
A few years ago I learned a valuable lesson regarding modding gear. I had a pair of speakers which I could listen to for hours, just a magical sound. The problem with them was though, I felt they lacked resolution. I bought several speakers with a similar sound, but with a bit more resolution. I came close, but when I put my favorites back in I always felt they had more magic. So, I decided to mod the speaker's crossover. It went pretty well and the extra resolution was there. Unfortunately, they lost the magic which made them so special.
Here's my take on this subject. Replacing a correctly spec'd A/C cable with an after market cord will have zero audible difference on a piece of audio equipment. That said, I also believe you, and anyone else who says they hear a difference, do hear a difference.
