I don't want to beat a dead horse here - but this post is an update "in the interest of science." When I made my original post about the Fireball, Richard Hunter, whose opinion I respect deeply, suggested I try the newer model with better bass response and get back to him. So I bought a Fireball-V, brand new. Here are my impressions.
It is a beautifully made mic, and it actually sounds pretty good though my Sonny Jr. I like its fundamental tone quality just fine - and this is in contrast to the original Fireball. But I doubt I'll use it much.
I started playing it through a Kalamazoo, where it simply doesn't have enough bass. I was pleasantly surprised when I switched to my Sonny Jr. 410, which of course has great bass response. Here, the new Fireball DOES have enough bass and I actually liked its tone through this amp. But I also found the downside of this was that it was overly sensitive to hand-holding noises - very easy to get it to deliver a thump, to the point where I actually had to turn the bass down on the amp to make it tolerable.
I compared it to some other mics. It is probably most similar to my Shure Beta 58, which is what I sing through now and therefore what I have to play through when I'm playing acoustically. Compared to the 58 (and every other one I tried) the output of the Fireball is quite low (and this makes me wonder if some of the "superior feedback rejection" claims don't stem from it simply being quieter at the same amp setting.) If I didn't have to sing and play through the same mic when I want to go through the PA, I would probably like the Fireball better than the Shure. But it isn't as good for vocals, which is the main goal of that mic in my setup.
As a pure and simple harp-mic I compared to a low-impedance 545 a customer sent me to eliminate the impedance matching transformer as a variable. The 545 has much more output and a warmer/fatter (and if desired, dirtier) tone.
I also compared it to a high impedance Shure CM bullet, which is my mic of choice - and found the bullet gives me much, much more dynamic and tonal range in response to cupping technique. The Fireball sounds almost as loud and almost the same tone cupped or not. If you like to "wah" - you don't want a Fireball.
So to me - the Fireball is nice but very one-dimensional. I realize some others like it - that's fine - everyone has their own style and gets to make up their own mind. But I don't want our beginning and intermediate players to get the wrong idea about this mic - it is not a substitute for a good bullet if vintage tone is what you want.
It does have a nice smooth flat response and it tolerates very high SPL's without distortion. That means it might be a good choice for recording or to mic an amp on stage.) I used it this way to record the sound of one of my Kalamazoo amps for my web site (playing through a custom bullet) and I think it did a good job of the recording.
/Greg http://www.blowsmeaway.com