I actually spent some time listening to both of models actually. I'm trying to collate my thoughts, take pix, and write up proper impressions, etc. Briefly though I'm highly impressed with both of them. The TU-05b is really more of a desktop level quality. Big sound, big soundstage, fluid, smooth, and the distinct tube signature. Shikada-san though for some reason capped the bass off to around 30Hz but he says it could go lower if he mods it.
The TUR-06 OTOH, is no slouch either. It's a hybrid but still an unmistakeable tube signature. The sub bass of the TUR-06 runs _DEEP_. And it's good rich lush deep too. It has a slightly smaller soundstage but still a great performer.
The fun side of me like the TUR-06 for it's bass, but the purist side in me like the TU-05b for it's pure Class A amp. Despite being inefficient though, it doesn't really generate that much heat.
I am so grateful to you mate for your thoughts. Though I don't doubt my perceptions the thing that has worried me is that they have been just mine and I always like others who are interested in components to have other peoples thoughts to go on as well so your thoughts are wonderful and I am relieved that you are hearing what I am hearing with the 05'.
I agree, the bass does not go as deep as others but I found with different tubes the amp can go a good bit deeper. I find the 3s4 stage the best for underpinning the bass tube implementation and things like radiotechnique or even better, Mullard make a not insubstantial difference in that.
Likewise, for the best of all worlds Dutch made Phillips Miniwatt are a good choice for better depth of bass whilst retaining a nice tight feeling.
If you had the amps longer I would have sent you some different tubes to try with it.
Once again, thank you for these thoughts and I am so glad your hearing what I am hearing and I agree that this can easily be thought of as a desk top amp and even better, freed from mains electric noise.
In fact, though one can listen to this amp connected to mains electricity I would not recommend it as the sound becomes ever so slightly grainy.
German Guy. I listen with either Final Audio Design Piano Forte IX or Beyerdynamic T5P.