OK, so some time ago I bought a Fiio E5. I've been using the E5 with a LOD on my 5.5G iPod mainly to add a bit of bass to my otherwise bass-shy Shure SCL4's. It does this very well, at the cost of a bit of muddyness in the upper sound registers.
Now, I had read about the "fudge" whereby you can slide the "bass boost" slider half-way between on and off and get a different sound out of this little amp. So I tried it last night for a while and really, really liked what I heard. Honestly, it made these IEM's sound perfect to me. Nice punchy bass and sparkly clear highs. A little less warm than the bass boost mode, for a more exciting, engaging sound.
That said, the fact that the phanton "middle position" of the bass boost switch also raises the volume leaves open the possiblity that the perceived qualitative differences to the sound are merely illusory. Could be that it just sounds better because it's louder, and when you bring the volume back down to where you had it before, you're still "locked" in that illusion of better sound.
I don't think so, though. I think the E5 is actually punching up the bass and sharpening up the high notes.
So I'm wondering what exactly is happening when you put the switch in the "middle position" and whether the unit can be modded
so that doing so is less of a fudge. I don't like the idea of leaving a two position switch "between" positions.
Hunting around in threads I found the following image of the E5's motherboard, which I've modified below to highlight the bass bosst switch:
Now, from that picture it's impossible to tell whether in the middle position is leaving all contacts unbridged or whether it is actually bridging all three contacts. My suspicion is the former, but I can't discount the latter. Any ideas?
Either way, it should be simple enough to modify the E5 so that its is permanently set to the "middle position." You either de-solder the switch and leave it at that, or de-solder the switch and solder in a permanent wire bridge. (You could even solder in an actual tree-position switch, but that is likely beyond my limited soldering skills given the size of the components).