tube amps sounding like solid state and vv

Tube Audio Design makes a ss amp (Hibachi) for those who like the TAD sound but don't want to deal with the perceived hassles (hot surfaces, maintenance, reliabiluty, etc) of tubes. The Hibachis also offer more output. The company claims that their ss designs sound similar to their tube units with modest feedback applied. IMHO, the Hibachis indeed sound more "tubelike" than many tube amps I've heard.

Marty

THe answer is probably marketing....and the need to continuously offer something a little bit different.

FWIW the underlying mechanism here is called negative loop feedback. It is a design device that is often used to reduce distortion. The problem is that in doing so, it is not perfect and actually *enhances* certain odd-ordered harmonics that the ear uses as loudness cues.

These artificial loudness cues are detected as 'hardness', 'harshness', 'brightness' and the like. Negative feedback can be used by both tube and transistor preamps. Those tube preamps that use it to excess will likely get a reputation for sounding 'solid state' whereas the careful transistor preamp designer can get his preamp to sound 'tube like' by limiting the use of feedback.

Component choice can affect things too, so its tricky to ascribe things entirely to one source. But in general you will find that feedback has a high collerlation with 'transistor sound'.

Typical tube circuits have very few components in the signal path, and are therefore much more transparent than SS designs. Victor Khomenko of Balanced Audio Technology has simplified the circuits of BAT's SS units, re-thought/re-designed their power supplies and helped them achieve a level of transparency/liquidity equaling that of some of the best tube designs. Well worth the audition. I'm a die-hard tube lover, and using his VK-D5 CD player, but- still a fan of his SS design philosophy.