amp 'Class' question

[Dave Blount]

I see a lot of love here for the Crown amplifiers which I believe to be a Class I design. How does this differ from a Class D amp, are not both a 'switching' amplifier ? I was told (can't remember where) that the Class I design mirrors somewhat that of a Class B ........ true ? if so wouldn't there be linearity issues in such a 'push-pull' device ?

 

[lovinthehd]

Crown calls them class D (at least the XLS Drivecore series).

 

[Dave Blount]

Crown calls them class D (at least the XLS Drivecore series).

Gotcha, so I'm still trying to understand the difference between the two ........

 

[WaynePflughaupt]

No expert, but AFAIK Class D is a relatively new type characterized by its light weight. As far as the others, here is a tutorial.

http://www.electronics-tutorials.ws/amplifier/amplifier-classes.html

Regards,
Wayne A. Pflughaupt

 

[ski2xblack]

Here's another (also covers class D, and others):
http://sound.whsites.net/articles/amp-classes.htm

Just don't get wrapped up in class A marketing hype.

 

[M Code]

Crown amplifiers are Class D using a custom TI processor/modulator chip.. However note now the amplifiers are assembled in China not Indiana..

Just my $0.02...

 

[M Code]

1 more note..
Be sure to get a model that has switchable input sensitivity so it can better match various preamp/processors..

Note that a few years back, 1 project we had when supporting Harman was to design a high-end AVR with 11 channels of Crown amplification..
(3) prototypes were assembled but then Harman top management pulled the plug...

Just my $0.02...

 

[Dave Blount]

Crown amplifiers are Class D using a custom TI processor/modulator chip.. However note now the amplifiers are assembled in China not Indiana..

Just my $0.02...

Not all Class D, at least according to their website. That's part of my question about differences between Class D and I, it appears that I is somewhat of a 'variant' of Class D.

IMO one of the advantages of push - pull tube amps is their ability to 'soften' some distortion, make it more euphoric if you will as opposed to transistor amps operating in Class D that I've heard to date that can be somewhat irritating.

I have not listened to anything Crown outside of the PA / Pro arena so I guess I need to delve further .......

 

[M Code]

My suggestion is that U go and listen to a Crown amplifier using your processor and loudspeakers...
Different amplifiers can/will sound differently depending upon the reactive load on its output stage.
Early Class D amplifiers had multiple sonic issues, mainly in the high frequencies for the brick filter used to remove the switching frequency.

However in todays' audio applications including personal, home, auto, and pro audio systems Class D is becoming commonplace. In our consulting biz we have done alot of Class D technologies listening comparisons using a controlled blind-testing switching system with matched levels, with very positive results. Due to their smaller compact size, better power supply efficiency, higher output power and lastly more affordable cost Class D solutions will end up being the final solution for most audio applications.

Just my $0.02...

 

[Craygun]

Class A whenever the application will allow!!!!!

 

[Craygun]

Class A is always waiting for the signal. while others may have a smaller transformer, they will need gigantic capacitors to do a good job.

 

[highfigh]

Class A is always waiting for the signal. while others may have a smaller transformer, they will need gigantic capacitors to do a good job.

What does "Class A is always waiting for the signal." mean? All amps are waiting fr the signal until it arrives. Does this mean they're "faster" than other amps?

What do you do with the wasted energy from your Class A amp(s)?

 

[PENG]

What does "Class A is always waiting for the signal." mean? All amps are waiting fr the signal until it arrives. Does this mean they're "faster" than other amps?

What do you do with the wasted energy from your Class A amp(s)?

Warm your home, make coffee, can be very useful..

 

[lovinthehd]

Warm your home, make coffee, can be very useful..

Didn't someone put one to use with welding as well?

 

[Verdinut]

The old BGW Model 1500 amplifier was called the "Arc Welder Special" because you couldn't kill it. However, it's audio performance was questionable.

 

[PENG]

Didn't someone put one to use with welding as well?

haha, may be he/she meant soldering.

 

[lovinthehd]

haha, may be he/she meant soldering.

No, think it was arc welding and in an article in one of the old audio mags....one of the great big monster class a amps....forget which one. Maybe urban legend. Not an ideal source for the welder either

 

[PENG]

No, think it was arc welding and in an article in one of the old audio mags....one of the great big monster class a amps....forget which one. Maybe urban legend. Not an ideal source for the welder either

Sure, for small arcs, for any serious arc welding it will be silly to use a class A amp. Actually, anyone who would use any audio amp to weld is silly, but then I am stating the obvious.

 

[Dave Blount]

What does "Class A is always waiting for the signal." mean?

I wondered on that one too ........... I'm guessing he was referring to it's output devices always having current flowing through them.

What do you do with the wasted energy from your Class A amp(s)?

why sell it back to Al Gore of course !

on a serious note, I guess you guys don't like Class A ? I'm assuming just because of there inherent inefficiencies. How about Class A A/B where the first 10-30 watts operate in classA and then slide into an A/B configuration. Those that I've heard of this design I thought to be superb.

 

[highfigh]

I wondered on that one too ........... I'm guessing he was referring to it's output devices always having current flowing through them.



why sell it back to Al Gore of course !

on a serious note, I guess you guys don't like Class A ? I'm assuming just because of there inherent inefficiencies. How about Class A A/B where the first 10-30 watts operate in classA and then slide into an A/B configuration. Those that I've heard of this design I thought to be superb.

I have a Parasound A23 and it's Class A for the first few Watts, like many amplifiers. I don't know of anything that runs Class A up to 30W, but someone probably makes them.

More accurately, Class AB means it operates in Class A for the first few Watts and then goes to Class B.

I like it, a lot. I may be wrong, but I think output devices may be more efficient now because this amp doesn't run as hot as many amps I remember from the past.