I bought a Dr.J effects Sparrow Driver & DI for bass because I wanted a DI option, an OD/eq option for my passive bass and a fuzz/OD option. I looked at stuff from MXR, but didn't particularly like the sound clips or the way they worked. I looked at lots of DI preamps, but they are expensive - I did order up a Mesa Boogie DI/preamp, but the sneaky bastards didn't actually have it in stock, so I cancelled and decided to try something cheap. Dr.J seem to be the 'high-end' part of Joyo. The pedal came today (took a week from China to Korea) and is well made. It looks fine to me; simple, well put together and solid. They could've put a battery in it, but at $65 delivered... The light is very bright. First impressions are good. Plugged in (using it on a battery): it doesn't have massive and/or wild range, just quite narrow but usable. With the drive down low or upto half the pedal is silent; as the gain goes up it gets noisier as you'd expect, not bad. The volume works with the drive knob and can get good volume, so you can use the pedal as a boost if you want - that might be useful. The OD/gain is just a light fuzzy boost, quite nice - could be used as an always on thickener or on more dynamic settings as a crunch channel. The mix does exactly as you'd imagine, but with the mix above halfway you start to loose note definition which'd be fine for some styles of music (when I'm doing punkier stuff). I kept the mix at about quarter way while practicing stuff for the band which the lead singer calls 'power pop' - and yes, I hate that name/genre too, so I might have to punk up my playing style a bit in subtle ways... The low and high knobs are eq knobs, but they don't seem to be centered exactly, so I set them both at 1 O'clock which seemed to give me parity with the pedal off settings. The low full on is very farty, but usable for three quarters of the range. The high brings in highs and might be useful to cut into the mix - nice to have these eq options. The harmonies knob: I've read that it's a presence knob, but I'm not sure how to explain that! I'm open to education here by you folks. Anyways, it sounds nice, kinda adds sweetness, a bit of balance between notes. For example, I was playing root/5ths through an E D C G progression, and it adds something nice and musical; an improvement over the standard tone for sure, but I can't really explain it - it kinda sweetens the alternate second notes (5th). I like this knob halfway. The DI: I haven't tried it yet. These are the settings I've found nice for the songs I was playing today - power pop! Here's a short video review: I like it. Cheap. Decent quality. Various uses. Small and will fit in a gigbag.