as an example, I have always preferred the sound of a tube based guitar amp over transistor amps without being able to say why

I'll tell you why, and give a specific technical reason. And also why the reason for this preference is totally unrelated to consumer audio equipment.

Electric guitar amplifiers are often overdriven, to create a deliberately distorted rock sound. When you clip a peak on a tube amplifier, the very nature of the technology causes those clipped peaks to become rounded off at the corners, producing a smoother, and yes, warmer tone to the distortion. There is a very distinct difference between the sound of a tube overdrive and a solid-state overdrive. This difference can be clearly heard, even by non-audiophiles.

If you don't overdrive the amplifier (say, for instance, you're trying to get a clean, Mark-Knopfler-esque kind of a sound), then this doesn't enter the equation, and there's little advantage to a tube amplifier. In fact, I've got a rather advanced rack-mount effects unit for my guitar, and it employs the 12ax7 tubes only for its overdrive circuit, and runs completely digital and solid-state for all its other functions.

The reason this doesn't apply to consumer audio gear is because, if you're using the gear properly, you aren't pushing it into overdrive. The only time consumer audio gear should clip is if you're pushing it beyond its specs.

Now, this is not to say that tube gear isn't better for consumer audio. I haven't personally compared tube and solid-state gear in the consumer audio domain. There are probably advantages to consumer tube gear. I just wanted to tell you why you always preferred a tube guitar amp.

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Tony Fabris