Hi Tom,
Got it!
OK, I understand better now the experience. The hum you mention sounds normal to me, in the sense that my PS-2 also sounds like this. I know this comes down a lot to personal opinions and expectations about how gear should work. The reason why this does not bother me is that when I’m playing guitar, I cannot hear that. It’s similar to the hum that you might hear from a tube amp when it is on but not being played.
The other sound on the recording, the intermittent crackling, does indicate something is not working right. We have seen with certain tubes that this goes away over time; particularly Sovtek 6550s can crackle initially and then settle down. However, your PS-2A has a 12AX7 and two 6L6s.
- Do you have a spare 12AX7? You could start by swapping that out and to see if the crackle goes away?
- Do you have a spare set of 6L6s? That would be the next thing to try.
See here for how to open the unit and swap tubes, How do I change the tubes and fuses in the Power Station
As this is new, Fryette warranties tubes for 90 days, so you should be able to speak with the distributor to get those swapped out for free. Does that sound a reasonable way forward?