Class D Amplifier

[SAPSEC]

What is Class D amplifier ? Better than class A or B ?

[dr bud]

it is a very efficient amp.it is still relitively new.not many people have bought in 2 this concept yet.i have not heard one myself.rotel has some class d amps out.they are getting good reviews.class d amps are what you usually find in powered subs.it is argued that they cannot do a good job providing a clean even sound through the 20 to 20htz range.i'm old school and have a hard time believing a 18lb amp can deliver 500watts a channel.

[Mr Peabody]

This link may be what you need, the actual definitions of the various classes are down on the page a bit

http://en.wikipedia.org/wiki/Electro...es_and_systems

More to the point: http://sound.westhost.com/articles/pwm.htm

I have a Class V which is similar to Class D, it is only 11 lbs and does 125x5. It definitely delivers the goods on power. Keep in mind most of an amps weight is the power supply and heat sinks, you take that away your amp is pretty light. So introduce a switching power supply and virtually no heat and there you go.

[O'Shag]

Class D refers to the use of Pulse Width Modulation, hence the reason why class D amps are generally referred to as Digital Switching Amps. Class A and Class B are the more 'traditional' ways of generating power, and you can easily find information on both on the internet. Most of the best amps run in enriched Class AB. Pure Class A operation does not automatically mean better performance all round, although it is generally associated with a more natural, true-to-life sound especially with respect to solid state. It is however, highly inefficient, with most potential power being wasted as heat, is far less reliable, and components such as tranistors, capacitors etc tend have a much shorter lifespan due to being suffering much higher stress loads, especially heat. Pure Class A amps will generally out-perform Class B amps in some important respects, but I have found that enriched Class AB to offer the best of all worlds. Class D is a different animal altogether in terms of power and signal modulation. The Class D circuit is MUCH more efficient, with 80% of the potential power being useable instead of wasted as heat. Class D runs cool.

I own the Spectron 1KW (1000 watts) serial #2 (built by John Ulrich himself). I also own the Spectron Model 10 preamp (serial #1 also hand built by John Ulrich) - a truly incredible component built to the highest specification using the finest parts (like Golmund or Burmester).

I own many amps of different sorts tubes and solid state from Audio Research to Mark Levinson.

You may have read that Class D is not as good by highest end standards as the more traditional topologies. An extended article was included in the Absolute Sound, where the consensus of opinion seemed to be that Class D was not ready for prime-time. In my opinion, this is not completely accurate.

I've listened to several Class D amps and some I don't like overall, but some I do like a lot. I owned the NuForce reference 9s briefly and did not like them as they seemed to be rather cold and clinical overall - missing 'that elusive organic life' quality. I liked the Jeff Rowland I heard, and especially liked the Spectron Musician 3. The older model 1KW I now own also sounds spectacularly good much of the time, especially when paired with the Model 10.

One thing that really grabs your attention right from the get-go, is the incredible speed/PRaT/rythmic drive of the 1KW. When I listen to my other amps after the 1KW, they sound, well, slower.

I think the most compelling aspect of Class D is that it can offer excellent all-round performance for the money (Spectron Musician 3). However, I still think that the most realistic sound one can have ie the sound of real life is best reproduced by high quality/high power tube amps (generally hybrid). Just my opinion. -but the best Class D comes close in some respects.

[Mike Anderson]

I have four ICEpower modules in my audio setup up (two 1000ASP modules and two 500ASP modules):

http://www.icepower.bang-olufsen.com...ter/ASP_SERIES

These are the same modules used in the Jeff Rowland amps.

They're driving Magnepan 3.6Rs through an active crossover. The 1000ASP modules go to the bass panels (for 1000 watts per channel) and the 500ASP modules power the mid/treble panels (500 watts per channel).

These things are a miracle. Hard to believe something so light, cool, and non-power-hungry could put out so much power at such a high sound quality, but they do.

Review:

http://www.6moons.com/industryfeatur.../icepower.html

[O'Shag]

Your right Mike, Class D technology is something of a revolution. Most commercial audio applications in areas such as automotive and TV audio have now pretty much universally adopted Class D. ICE power - the Bang & Olufsen product, is very good indeed. An alternative to ICE power is Tripath. My Spectron Class D amp is not small or light, but most of the latest commmerical versions of class d amps, are.

[topspeed]

Excellent post, O'Shag.

Switching amps are the wave of the future. Most of the switching amps I've heard (Rowland, ARC, PS Audio, BelCanto, Spectron) do a very good job of melding the attack and depth of great SS amps (big Krells) with the liquidity and sweetness of tubes (ARC). If there is one thing they do better than either however, it's transient response. Backgrounds are inky black and because of the huge contrast, transients are lightening quick. This is likely the "pace" that O'Shag was referring to, and I concur wholeheartedly!