Hey! And Happy Friday to you all :-)
I also play a bit of Mandolin on the side, and know another banjo player in town who also plays the mando. I'm curious if there are many banjo players doing this, and how most tenor banjo players feel about the mandolin.
Of course, they say Barney himself was originally going to play mandolin but took a banjo because of the cost of it, so there's a relationship between the two instruments right from the start :)
I play mandolin because I have a pretty quiet electric mandolin which I can use for practice late at night, when my neighbors don't want the treat of my banjo playing quite so much. Also, I have a to travel a lot, so I have a small, inexpensive mandolin-type instrument which I take with me so I can get my playing in.
So basically for me, the mandolin is a back up for when I can't play my banjo - I think it's important to play a bit every day.
I play mandolin exclusively, but am toying with the idea of getting a banjo so I can be heard at sessions, so here I am. I see a fair amount of cross overs from tenor banjo to mandolin and vice versa.
Having ridiculously small hands, the mandolin is ideal for me. A friend is going to lend me a tenor banjo for a bit to see if my hands can adjust.
Is this about the volume of the instruments, or the tone? I keep the back off my banj so that's it's not too frightfully loud. It's lovely and soft sounding - I don't think I'm competing head-on for volume with the fiddle and pipe players, but acoustically it's in a different place so that you can pick it out quite nicely. I can see how this could be a problem for the mandolin, the tone does tend to hide itself a bit.....
I think that the neck on my banjo is a little bit deeper than on my mandolin, but it's not something you'll need big guitarist hands for.
Good luck, and welcome to the tenor banjo!