Thanks guys, once I retire (meant to be end of this August) I have more free time and would like to learn a bit of analog electronics again. Believe it or not I have a Honors degree in electrical and electronic engineering and did all the transistor theory etc. a very long time ago when I was young. It will be worth a revisit so I can teach my boy at the same time.   Oh I nearly forgot one funny thing I noticed just a bit earlier when playing with a tone generator app is that one of the amps rotary encoder has a switch so you can push it in but the other one doesn't. They look identical but then that is AliExpress for you haha That said I do like the size of those amps as they sit nicely on the sides of the shoulder tucked away rather than a big box stuck some where.

The small amp is missing the LED display. With big home theatre amps have a LED display to show the volume setting to go with the infinite adjustment to the rotary encoder dial. Say minus 40dB to minus 20dB to 0dB setting. The finite adjustment to the B linear potentiometer is easier to follow. Say 25% to 50% to 100% setting. This is why I don't like the rotary encoder dials. It is just guess work, trying to work out the percentage of volume level when you have a dial that just endlessly goes round and round.

There's a 99% chance a fly will get stuck on it, too. So my advice is put a fly on it anyway and get it over & done with.

Thanks @DalekDucky! I have joined the DWS of Canada, but I'm afraid I'm not impressed. Aside from the fact that I appear to be the only member on this side of the country, the website has not been updated since covid, and the only way they want to stay in contact is through Facebook or Instagram. I cut off both of those last year. I still have an email, old man that I am, and am weirdly happy about it not sending any more info about me to Mark Zuckerberg... So, the upshot is that I paid my dues, got a nice laminated membership card, and a printed letter inviting me to connect on Facebook, and "click the link" if I wanted more info. Click the link. On the sheet of paper. The trailer goes on the long list, I guess. I recently opted NOT to push for promotion at work, putting quality of life ahead of upward mobility (besides, I'm a middle-aged white guy. No one wants more of them in management!) so, until one of my plays hits the big time, it's not going to materialise any time soon. But thanks for the information - always welcome!