Audio Systems: Shure SM58 Mic Volume, xlr connections, channel volume

Question
I have an older SM58 (has the 1/4" phone jack plug with a screw on adaptor for the mic end). I recently used the mic for a live performance and it was much lower in volume when compared with other, newer mics with xlr connections. Even with the channel volume maxxed I couldn't compete with the others. Looking to find out if I need a new mic or can an accessory like a DI or preamp help out.

Answer
I've been working in pro sound for a very long time and can't tell you when I've seen an SM58 with a 1/4" plug instead of an XLR. Tell me something is the 1/4" TR or TRS? If it's TR it's unbalanced. There have been vast improvements in the 58 in it's 30 plus years on the market. Just in the last few years they've made it more sensitive, given it a better frequency response and created filters that make it easier to use in live application. I say if you can afford it get a new one.