The product is of a decent quality and definitely it is not a toy. I won't recommend it for everyone - I'd rather expose what it's been used for in my case:
I use it for sampling, due to a fact that I'm also using some great sounding oldschool A/D converter with Mic preamp and +48V Phantom power supply, which cannot take the feed from cheaper sounding high impedance instruments, such as keyboards and sequencers. The noise level before was greater, because of the higher input gain level on the preamp. Now I got some extra 10dB of headroom so the preamp produces less noise overall. Not only that, the stereo separation has been improved too. You can't however use this device on a busy mix which feeds the JPC input, unless it's a "mastered" laptop, AV, iPod sound. See, I use it for tracking individual sounds and each time I load more bass, I turn down the gain to avoid picking on the A/D. So as the high tones are recorded separately with a higher gain adjustment on my mixer. For recording situations this is OK, but when performing live, you don't want to fiddle around too much with the gain control each time you sweep through your instrument FX/EQ, then maybe you should automate and control your input's frequency content balance or just get another Radial Engineering product that fits your application.
I'm also using J+4 which sounds a little different and I do experiment with both for tracking. J+4 feeds my other converters which don't have a preamp.
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