I have seen several reviews here and on youtube about the John East P-Retro preamp for precision basses. Most reviews are very positive. On the other hand, I also see that many people on TB who installed one of these pre-amps put them up for sale a few months later. If this is true, there must be something about the pre that turns players off after a while. If you have owned the P-Retro in the past or currently use one, I would like your comments on why you decided to sell it or keep it. Thanks.