On Mon, 27 Apr 2009 13:20:59 -0400, me > wrote:
>On Wed, 22 Apr 2009 13:19:01 -0500,
>(Matthew Russotto) wrote:
>
>>In article > ,
>>Clams Canino > wrote:
>>>
>>>That's one of the applications I had in mind.
>>>It always seemed to me that if you overdrive an amplifier into a "class C"
>>>condition that the resultant distortion outta be the same distortion for the
>>>same paramaters. None the less, there is a difference that guitarists can
>>>hear, and if they try hard enough to teach us - the normal ear as well.
>>
>>A transistor amp will typically behave linearly until you saturate it,
>>then it clips. A tube amp will compress first, long before it clips.
>
>I confess to being only marginally familiar with the specifics, but
>the only (guitar) distortion device I ever built with solid state
>components intentionally clipped the waves. I've never heard a solid
>state amp that would clip in any kind of a desirable way (sound) even
>when cranked hard, and at that point you seemed to be just beating the
>snot out of it.
>
>A tube amp seems to long to be cranked all the way and responds
>gracefully (Perhaps that's the compression you are talking about).
"Class C" refers to the bias point, not the amount of drive. There
are 3 major classes of bias on tube and transistor amps, Class A,
Class B and Class C. There are several sub-class of bias Class AB for
example. I won't go into details but Class C is never used in an
audio amplifier, only RF amps.
Class A biases the device in the middle of the liner portion of it's
operating curve. Class B sets the bias at cutoff and Class C sets the
bias way beyond cutoff. Class AB sets the bias before cutoff at the
bottom end of the liner portion of the curve. Class A and B are never
driven into saturation if you desire a liner output. Class C is
always driven into saturation.
Class A is the only class that will give a liner output when a
single-ended power amp is use. Class A, AB and B can be used with a
push-pull output and AB and B will give greater efficiency than Class
A but can only give a liner output when used in a push-pull circuit.
Comparing transistors to tubes is like comparing apples to oranges.
Both apples and oranges are fruits but they look, taste, feel and
smell different. Tube amps and transistor amps both amplify the
applied signal but they do it differently. Tubes are voltage
amplifiers while transistors are current amplifiers.
Different devices behave differently when driven into either cutoff or
saturation. Even different types of transistors have different
operating curves.
End of Electronics 101.
To the best of my knowledge, Toyota has not used tube amplifiers in
their cars for at least 50 years. Why was this posted to a Toyota
newsgroup? Mistake?
Jack j