I normally use one of my many, very good linear lab supplies. I was readying a 2nd QMX I bought to lend to an old USAF diddybopper living in a memory care facility. An adjustable lab supply was not a practical PSU in his situation, particularly as I'd have no way of preventing the voltage from being changed by accident.
So I thought a wall wart would do as all I needed was 100 mA for Rcvr operation. Bill was not going to get on the air. Sadly, I never got a radio to Bill he could use before he passed away. The FRG-7 was too complicated and he didn't stay up late enough. I found a 12 V 1 A wall wart, so I thought it made sense. I'm generally used to them being *below* rated output. I'm also used to seeing 176 V on the ground lead on 2 wire mains powered T&M kit from China e.g. the F***Tech FY6800.
There is an old proverb among the Unix greybeards. "Be tolerant of what you accept and strict about what you produce." I see no reason that should not apply to power inputs for QRP kit.
Have Fun!
Reg
