Hey all, I've had my Yamahiko single sensor pickup on for over a month now and just want to give my take on it.
It is not the holy grail, it is not MBOL, it will not radically change your world. At the end of the day it is just a piezo pickup. However, it's a damn good pickup.
It gives you plenty of everything: treble, mids, bass. The bass is not as exaggerated as with a realist so if you're used to one it might sound a tad thin. I came from a lifeline so that was my thought but then again with the lifeline I was always using the HPF and bass cut on my Acoustic Image Clarus S4 to tame the low end so now it just means I have a nice solid low end with the hpf off and the low set flat.
With a flat eq this thing does not have an amazing tone. However since it gives you so much of all the frequencies you can really "shape" the sound. With the lifeline, there's like no treble at all. With my AI head and EA Wizzy 10 I could boost the treble EQ all the way and cut all the way down with no noticeable difference. Not so with the yamahiko.
If it's a low volume gig, cut some mids and you have a really nice Realist-like sound (with adjustable treble). When the volume comes up or the crowd gets noisy uncut the mids and you get a really cutting tone that is great for hearing yourself with clarity on stage. And it helps you to hear yourself without having to turn up the volume too much.
The biggest thing I've noticed about the yamahiko is its ability to "thump", with the right acoustics it can actually sound like a microphone since it responds to dynamics. If I dig in, more comes out of the speaker just like more comes out of the bass.
Another thing I love about this pickup is how well ghost notes come out, those little eighth note and triplet accents in walking lines come out much better with this pickup.
The arco isn't the greatest but I'd say it's incredibly sensitive to your arco technique. While the tone isn't phenomenal I think arco heavy people will appreciate how well the pickup amplifies all the little nuances of your technique. In other words it will really put out what you put in, if your arco is working well acoustically it will be quite alright, if not, it's gonna sound terrible. So really it's a garbage in, garbage out scenario whereas I feel pickups like the realist can almost mask bad technique IMHO.