One thing, envelope filters are very different from pedal to pedal. Lot's of parameters in the circuit, lot's of design decisions the makers make and "bake in". One huge difference is band-pass vs low-pass, for example, although even two different low-pass filters can sound very different. So the QTron may be much better for your use, or maybe not, and other's experience will only be tangential because different basses, strings, EQ, amps, and playing styles all impact how an EF works for a given player.
I own quite a few different EFs and I have a hard time letting go of some of them because they have a sound the others can't cop. That said, I did sell my AW-3, and I held on to my QTron+.
I would say the Qtron may be something you like, but if at all possible try before you buy. Also, buy used if you can, you can probably pass along the one you favor less. Or maybe you'll be like me and want to keep them both for different sounds.
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Last edited by HolmeBass : 02-17-2014 at 01:37 PM.