An interesting experience with power cable.

That sounds about right. Wait till you have 4 different one's and you have to try all combo's, ouch. Had the same experience with power conditioners, if anything the amp sounds worse, but everything upstream sounds better. A great step up for my amp that I tried was a gutwire ultimate ground cable. Dropped the noise floor significantly, opening everything up just like the experience you had with the power cable. I also took it one step farther, adding an audioquest splitter and removing the center pins connecting to the amp and streamer. The one cable works on both now. $500 isn't cheap, but a huge improvement cable wise for the amp, more so than a power cord. Maybe you can find one used like I did. Read up on that cable if nothing else, just another way of making improvements. Just my 2 cents of experience.

Sounds like your new cable is undersized for your amp.

@carlsbad That is possible. I do have a monster of an amp in terms of size. 90 lbs and it has a 2,000 watts toroidal transformer in the supply or something like that. I suppose that’s a lot. One thing I have to note is with the new cable into the amp, it doesn’t sound like it’s lacking in power, it seems to my ears that the amps are more hyper-focused and felt like I’m hearing the shortcomings of my upstream, in this case the dac. The thing is I can't imagine the basic stock cable can be less "undersize" than the new one I bought. 

@gammamike Yea $500 is too expensive for me right now. I have to remember what you say in the back of my head. I’m currently looking into acquiring the dac that is supposed to pair with my amp, some sort of current injection technology. Thanks.

Just a heads up, a quick A/B test is never a good indication. Have the cable on the component for 24hrs drawing current before you sit down for critical listening. Let it all settle. This is if the cable is broken in. If it’s brand new, allow about 200hrs before you judge it.