About Dual Bananas…

Or… “Sometimes the simplest things are the most perplexing.”

It all started when I decided to replace the ancient and annoying speaker screw terminals on my Dynaco ST-70 amp. I found some pretty dual banana terminals on amazon, ordered them, and went to install them. Straightforward, no?


Here’s a pic of the jacks I got.

Looks fancy with gold plating. But cheap materials!

Look nice. Even includes a second nut to clamp the ring lug with, nice again!
Little did I know the horrors that awaited me…

Cheap plug, disassembled.
  1. These are very poorly made. The material is some soft pot metal that is badly threaded and thinly gold plated.
  2. The threaded post metal is so soft I stripped two of them while trying to tighten it enough to keep the terminal from spinning. (see pic)
  3. The alignment keyway is quite small and the plastic shoulder mount is so soft, it too stripped immediately. That means the post wire hole isn’t vertical any more. Also, the stripped keyway means the finger-grip is just as likely to spin the post as it is to loosen or tighten on a wire.
  4. Lastly, the lack of electrical ratings should have tipped me off, as they were non-existent. (One similar looking jack was only rated at a wimpy 30V, 5 amp.)
Cheapo post, threads stripped.

These are the jacks I’ve used for years.

And should have stayed with, Pomona 6883 jacks.
These are used in electronics labs everywhere. Although they superficially look similar, the much higher quality materials and construction are obvious.

Pomona 6883 dual banana binding post

These are much more sturdy, the threads don’t strip, the post locking keyway actually works, and they’re rated at a solid 30A/60V.
Also note the shoulder right below the wire hole. That allows it to securely grip the wire, unlike the cheap jack which just presses against the plastic shoulder mount with a washer.

And get the matching Pomona banana Plugs in black and red, # 1330-0 and #1330-2 respectively, rated at 15 amps.

Quality plugs: Pomona 1330

The spring tension on these hold up for years, unlike the cheap but “pretty” ones. They have a strain relief hole and will accept up to 12 gauge wire.
Plus, you can stack them, very handy.

Last Updated on 2021-07-07 by Daev Roehr