confused about 20 amp power cables

Check the fuse rating on the back of your amp. It’s probably a lot less than 20A. :) I don’t have access to the manual but I saw an image which specified 1500W on the back. This should be around 12 Amps. A 15A circuit is generally rated to 1800W, a 20A circuit for 2400, so definitely a good thing you are using a 20A circuit!

Any decent conditioner should also have a built in breaker, so in the unlikely event you overload it the breaker should trip quickly.

Generally speaking, there’s not a lot of difference between a 20A outlet and 15A outlet. They both have to be built for 20A due to the NEC allowing a mix of 20A and 15A plugs on a 20A circuit.

That’s not to say the wiring in the wall doesn’t need to match the breaker in your panel, it absolutely does. :)

The thing to consider for the long term is how much of those 1500 watts do you actually use while listening? The more of that you use the more likely you can make your line sag.  To find out use a voltage meter like this one.  Leave it plugged in and pay attention as much to the N-E as the overall voltage.   This will also help you understand how much voltage variance you have due to seasonal/major appliance use and how much is due to your gear.

@mintakax Are you the individual who purchased a PA 3100 HV locally in CO? If so, I work with the previous owner from time to time as well.

FWIW, the optional PS 3000 HV power supply should be on your consideration set for down the road. It significantly improves the performance of the unit in terms of coherence, soundstaging, and control. 

@blisshifi --Thank you. Nice to know about the 10A fuses. This is really an amazing amp and I look forward to using a decent PC. 

@mintakax The only benefit you will get from plugging it into a 20A circuit is that likely that circuit would be a dedicated line, so it would be isolated from other noisy electronics on the same circuit. 

I am an authorized T+A dealer, and I can tell you that the most powerful fuse in the unit is 10A, so it for sure never draws more than 15A. If anything, it actually only uses less than 5A continuously.

Actually for both my own T+A A 3000 HV and PS 3000 HV, I replaced the 20A IEC with 15A ones. This opened up my ability to choose from many more available power cables with 15A connectors.

And in case you ask, no, a 20A cable does not deliver more current than a 15A cable if it is not needed. Quality high current cables (e.g. 10AWG conductors) can do wonders to help that amp sing. 

Congrats on your purchase of a fantastic amp.