My only extensive experience is with simaudio's p-5 preamp, which is fully balanced. Unfortunately though it only has one balanced input, but it is an excellent preamp no doubt. No listener fatigue, except maybe when played too loud but that could be said with most other preamps or components. I whole heartily recommend it, just consider matching of components is critical at this level of performance. Now I am using the atma-sphere m60 amps, before i was using sim's w-5 power amp, and I could see using a tube preamp would serve me well with the m60's.