>      Yes, there is a "tube sound". Is it better than a well designed solid
>     state amp? I don't necessarily buy into it. Between a properly designed
>     solid syate amp and a tube amp run within it's normal parameters, there
>     should be little if any difference. It is only when you are stressing
>     the amplifiers where you can detect major differences betwenn the two
>     amp types.
Jumping in here.  
Some of the effects boxes which are designed to add "tube" sound will 
run the tubes in a starved condition - the voltages fed to these tubes 
will be several times less than what they normally use for operation.
This is actually very clever on the part of the designer because it 
does not hurt the life of the tube but it does cause the tube to go
into distortion a lot sooner than otherwise and it allows more control 
over the sound.
A typical low-level amplifier ( 12AX7 ) runs at 150 to 300 volts  on 
the plate.  The PAIA design for tube pre-amp uses 45 volts.  Lots and 
lots of really nice warm tube sound!
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