Here are some pictures of my second prewar banjo. It is a 1923 “The Gibson” Five String Banjo. I converted it from a trapdoor type tenor to a modern-style 5 string resonator banjo. It features a ball bearing brass tone tube (which is hollow about 1/2 inch o/d). This tone tube has 59 holes in it located all around the lower inside of the tube. It is lightly plated with a silver like color that has little or no shine to it. A little buffing  in a small area showed that it has the yellow brass color underneath the plating although not as yellow as you might expect. I had the metal in this tone tube tested and the content is different from the normal red brasses that you see today. This alloy in this tone tube has a lot more zinc in it than the normal red brasses but not enough to be classified as white brass. From what I have read about brass alloys, I get the idea that a white brass would be too hard to bend into a circle without breaking. This tone tube rings like a bell when struck with a mallet. This tone tube sets on 20 steel ball bearings positioned all around the top of the shell. These ball bearings sit atop little washers that are in the bottom of the holes. These holes are shallow enough that these ball bearings stand proud of the top of the shell. Note that there are no springs under these ball bearings. This tone tube rests on top of these ball bearings and is secured with some little wire pieces that fit into some of the holes in the tone tube and in the shell. The whole banjo only weighs around 7 1/2 pounds. The absence of the 3 pound tone ring doesn’t seem to hinder it’s sound. It produces a pleasant tone with plenty of volume. I realize that a lot of banjo pickers will turn their nose up at this banjo, but they may do well to listen to it before they make fun of it. I think that this is a valid pot assembly design that Lloyd Loar was involved with until he left Gibson in 1924. In 1925 someone at Gibson decided to weld (or solder) 2 extra pieces to these tone tubes. One piece was welded to the lower outside of the tone tube and made the diameter 11 inches instead of 10 1/2 inches. The other piece was welded to the top inside of this tone tube and made it in effect the first archtop pot. They also added springs under the ball bearings. In my opinion these changes detracted from the sound of these banjos. I think that after Loar left Gibson, someone got off track and went in the wrong direction with these tone tube pots. After about 3 years of the ball bearing Mastertones (25 to 27) with the added hardware and springs, they removed the ball bearings and tone tube and added the 3 pound tone ring to these pots. I read somewhere that Vega was threatening to sue Gibson because they felt the ball bearing design infringed upon their scalloped tone ring idea. I don’t know if this is true but it could have been a factor in these changes also. I won’t argue with the success of the Mastertones, (both archtops and flatheads) but I think the first design of the ball bearing pots (without the springs and added pieces) was a good design. This pot is a 10 1/2 inch diameter. This one has a curly maple sunburst neck and resonator with a Cremona like color. I like the lighter weight of this banjo,too. This makes 2 pre-war tone tube Gibsons that I have. This one is definitely the best looking one.

Update, September, 2018:

This banjo now belongs to Charles Mann of Gadston, AL. I traded it to him for a 5 String Dobro. I still own the other 2 pre-war conversions listed on this site.