Solder was originally designed to be a conductor junction glue, and people who assembled electronics (tube stuff at the time) were reminded of that point. That ’metal to metal contact’ was the only real conductive pathway.
Solder evolved into being as a conduction interface, which was an advantage in some ways and a degradation in others.
With regard to AC power connectivity, the proper way to do things is to loop and lock the wire conductor to the terminal point, and then use solder as an anchor. You will see this done in properly made audio equipment and you will see it being done in all older tube gear in all connectivity junctions. It’s kinda the law of the land in that area of connectivity. Yet you see this critical safety point being volatilized all over the dang place. It’s why a raw AC connector will generally have a hole in the connection terminals in the inner chassis mount side of it. If one is not using pressure clip type connectivity for internal AC wiring and is using solder, they must use, must use ...ac connection terminals with the wire loop hole in said connector designs. And then loop that wire through the hole and then solder. An alarming amount of audio gear from various places violates this safety standard.
Circuit boards were a step up in ability to be mass produced for electronics in general, but circuit boards have been a sound quality degradation issue for quality audio equipment, overall.
Some people hear the noise created by these junctions and materials dissimilarity issues... and think and hear of it as an expanded base of micro detail, but they’ve never heard the difference of the exact same circuit assembled in free air with full sized components done in metal to metal contact methods --vs being done via circuit boards.
Mass assembled circuits based on solder and circuit boards was a price race to the bottom.
This most definitely happened in the world of audio as well.
In audio, the end result...was a industry wide loss of a higher plateau of sound quality and a near permanent mistake in how people listen and perceive, being introduced.
How does one walk into a factory, a show room or a trade show display room and say out loud, ’everything here could sound better but...now exists as a permanent step down in audio quality’.
You’d be be tossed out on yer butt, at the very least, as your astute comment makes 99% of all the audio business models non functional in sales, if they followed your moment of truth. Doing it right for some (surface mount digital and analog) is flat out impossible, and the others, the precious few remaining... might suffer a 25-50% to as high as a 100% retail price increase.
Its a thing.. a stinky thing.... dead and run over a long time ago.... that sits there in the middle of the audio road. There are ways of making audio gear sound better and this is one of them. Many (of these quality improvement methods) cost more than ’normal’ methods of design, in order to implement them. The sales department, accounting department... and general market viability - likes circuit boards.
Some extreme gear is built this way for this particular reason. It’s an important reason. (MFA Octal tube based preamp) Once you’ve heard and recognized such a revelation in audio, you likely won’t go back, even if it limits your purchases and you have to work harder and spend more to find them. It’s not a thing for fanatics, it’s a simple case of going back to what was originally better. It’s a norm in functionality trying to hold it’s ground...and is about sidestepping the modern downgrade.
