There was a time in the early 1970s when the only banana plugs I could find in the Toronto area were the solderable type (I still have some speaker cables with those plugs attached.)

It certainly isn't necessary, given the significant voltage/amperage of high-level audio signals from a power amplifier. If you were talking about the tiny output from a moving-magnet or moving-coil phono cartridge (a few millivolts--thousandths of a volt), then losses might be significant.

I haven't bothered soldering banana plugs for years. You could take this to ludicrous extremes, the way some tweaks are prone to do--and solder the entire signal path from the amplifier output terminals to the crossover board inside the speaker, but there's no significant--or audible--loss with high-level signals and typical speaker posts and banana plugs so don't worry about it.

- Alan

Should you add solder to bare wire before inserting them?

no

I wondered.
I hadn't heard of anyone doing it before until about two months ago when out of the blue two different people told me they had done it and both said they noticed better SQ.

one was my mom.....I'll never live this post down...

These Radio Shack banana plugs let the wire hang down to reduce that problem. I also like that I know that when the wire exits the bottom, they are oriented with the proper polarity, so I don't have to squint to try to determine "red or black". The knurled knob in the back of them tightens down on the wire. They also accept the 12 gauge wire I'm using.

I love banana plug discussions.

Nice plugs, Mark! And I agree that it's always important to let your wire hang down. . .

--Alan

At least in public.
What makes your wire point up is no one else's business.

Ha, ha! My first LOL of the day. . .

-Alan

all this reminds me of the song i hear on Galaxie sometimes:
The Big Bamboo, by Mighty Sparrow.