[china]

I would like to find out about class "d" and class "t" amplifiers. What makes them so special or not so special and what is the difference be-
tween the two. What is the major advantage to these amplifiers. Thanks
for reading this. As always, all the best.

[Kevin Haskins]

There really is no such thing as Class T.  It is a marketing term used by Tripath to promote their Class D products.

The advantages of Class D are high efficiency and when properly implemented better sound quality.   They also tend to be very forgiving of loudspeaker loads.

[Steve]

Only thing that bothers me is the RF emissions that some seem to spew out, degrading the sonics. If the offenders can lick that problem, I say why not.

[Occam]

......The advantages of Class D are high efficiency and when properly implemented better sound quality.   They also tend to be very forgiving of loudspeaker loads.

Indeed, properly implemented switching amps do tend to sound far better than improperly implemented switching amps.

[JeffB]

The 'T' of course stands for Tripath.
Their marketing literature indicates that the output is analyzed to see how closely it matches the input, and the switching is adjusted to compensate.
Whether this is significant enough to distinguish it from class 'D', I'll leave to others to decide.

[Kevin Haskins]

......The advantages of Class D are high efficiency and when properly implemented better sound quality.   They also tend to be very forgiving of loudspeaker loads.

Indeed, properly implemented switching amps do tend to sound far better than improperly implemented switching amps.

    Make a general statement and you really open yourself up to abuse don't you?   

[Occam]

The 'T' of course stands for Tripath.
Their marketing literature indicates that the output is analyzed to see how closely it matches the input, and the switching is adjusted to compensate.
Whether this is significant enough to distinguish it from class 'D', I'll leave to others to decide.

Jeff,

As far as I know, all commercial switching amps use negative feedback (comparing input to output and making adjustments accordingly), which is exactly what you described. Nor is Tripath unique in adjusting its switching frequency. Class T is simply a name for their specific implementation of their switching amps. Gleaning technical understanding from marketing hypebole shouldn't be anyones preferred method.

[dwk]

Jeff,

As far as I know, all commercial switching amps use negative feedback (comparing input to output and making adjustments accordingly),

For completeness, the TI Equibit amps (Tact and the Panasonic XR receivers) do not employ negative feedback. The PCM->PWM conversion is direct and runs open-loop as there is no intermediate analog representation for comparison to the output. This has some advantages and some disadvantages, but as far as I know it's unique in the market.

[ctviggen]

I think one thing that's different is how they "sample" the incoming waveform in order to create a pulse width modulated output.  For instance, Nuforce uses a triangular sampling. Check out:

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6519167.PN.&OS=PN/6519167&RS=PN/6519167

I think the UcD modules operate in a different manner, though it's been a while since I've looked into that technology.