digital amps? huh?

Originally posted by ohskigod
what is the difference between a digital amp and a solid state one.

The solid state one hasn't had its nutsac removed, and might actually sound good.

Use whatever preamp you like, tube, solid state, passive.

Cheers,
Russ

A digital amp actually does convert the incoming analog signal into a pulse width modulation (PWM) signal. The pwm signal is a digital signal that varies the "INTENSITY" of the signal (volume) by increasing the time domain of the wave. The longer the time domain, the louder the signal. It is important to remember that this signal is PWM and that the frequency of the signal is not determined by a sampleing frequency as it is in a PCM signal, the frequency is encoded in the signal by a switching factor. The more times that the signal turns on and off, the higher the frequency of the signal. In a digital amplifier the circuit board acts as a complex switching unit, the individual bits are carried through a complex of switches (transistors) that turn on and off very rapidly, this creates the gain (amplification) that the signal requires to drive a pair of speakers. At the end of this whole circuit is a DAC to reconvert the PWM signal into an analog signal. It is quite elegant when it is done correctly.

Are we talking about Class D amps?? If so, the following things need to be addressed:
-Class D is not digital. Its PWM (pulse width modulation... sorta like digital with 'offs' and 'on's, but not the same).
-Class D is switching, and generally switching amps or converters or whatever are quite efficient. Class D amps are generally 80-90% efficient instead of 50-60% efficiency of AB amps, or the 10% of less efficiency of Class A amps. Efficiency = doesn't get warm.
-therockman... all correct except for the DAC on the end... its actually a second order filter using an inductor and a cap. By filtering everything over a certain frequency, you can "shape" the digital looking signal into the nice audio signal.

Class D is a pretty cool thing, and has crazy potential, but although its been around since possibly the '50s, its only recently become popular with audio and has to have some kinks worked out of it.

Class T, as far as I have read/seen (which isn't much since Tripath is so hush-hush about their stuff), is only a digital feedback, and the rest of the circuit is analog just like Class D. I might be wrong on this, and I'd be more than willing to say I was wrong if someone could prove it either way.

All I know is the one channel I put together (so far) only has 1 (one) chip and about 5-10 other components (resistors, diodes, and such).

(to the tune of "C is for Cookie"): T is for Tripath...

Is there some confusion here between 'digital amps' and the quite-analog amp-on-a-chip a la the 47 Labs' "Gaincard" and the "Gainclones" thereof?

You can try a Tripath digital amp for $29 from Target:
http://www.target.com/gp/detail.html/sr=2_2/qid=1093281089/ref=sr_2_2/601-3442379-6041720?%5Fencoding=UTF8&asin=B00009W44B

You can build your own Gainclone.See, e.g.,
http://gainclone.com/phpBB2/viewforum.php?f=2

or,
http://www.mhennessy.f9.co.uk/gainclone/

or,
http://www.decdun.fsnet.co.uk/gainclone3.html

or,
http://www.euronet.nl/~mgw/diy/amps/uk_geenkloon_1.html

you get the idea...

Originally posted by mhardy6647
[BIs there some confusion here between 'digital amps' and the quite-analog amp-on-a-chip a la the 47 Labs' "Gaincard" and the "Gainclones" thereof?
[/B]

That appears to be the case. Atleast on my part.

I have been checking out PS Audio stuff and it "looks" good to me in silver. Still reading lot's about them. As long as they have the oomph of the many other amps on the market maybe it is a good choice. PS website not having them on sale anymore but there are online dealers with a good price. Just wish locally it could be heard.
...........aahhhhhh....fun to think about this stuff.
..........Pat