What are the advantages to a Class A amp & what are the trade offs?

A big advantage of Class A amps is that by the standards of any AB amp they have a hugely overbuilt power supply and they can drive low impedance loads without faltering.

One of my systems has a pair of Class A monoblocs that put out 45 watts a channel in stereo configuration, but 500 watts bridged into a 1 ohm load.  Hard for AB amps to match that.  They are also large and heavy, if that matters to you - mine are over 100 lbs. each.

If you don't run difficult loads, then the choice comes down to sound vs. power usage and heat production.  I really like the sound and still own 4 Class A amps, but I use an AB tube amp to run my main system which has quite efficient speakers.(92dB)

@viridian4, The Krell KSA amps are true Class A. They have a feature called "Sustained Plateau Biasing." where they have a sliding bias feature that anticipates the loudest signal and then biases the amp into more Class A wattage before the signal is amplified. There are 4 bias levels and when a higher bias level is triggered it stays at that bias level as long as the signal strength justifies it. All the signal going through the unit is amplified in true Class A but if you are playing quiet music it only uses the lowest bias level. This is why the amp runs hotter when it's played loud. But it's important to note that at no time does the amp run in Class A/B.

Some amps run in pure Class a for a few watts then switch to Class B. The Krell does not do this - it only runs in Class A.

There are a couple other companies that use a similar Class A biasing feature in their modern Class A amps. They, like the Krell series, only run in Class A but don't consume their full power unless demanded by the input signal.

@sfischer1 I own a Baratza Forté coffee grinder, a smart scale, and a programmable kettle. My coffee is pretty consistent from day to day. I watch my coffee to water ratio, you know. I use the Kalita pour over system, it’s simple and it works well. An app on my iPhone that pairs with the scale leads me through the steps and provides a timer.

Every office I’ve ever worked in has had atrocious coffee. I used to bring in my own beans and a little French press to make a fresh cup so I didn’t have to drink burned coffee or that awful Keurig stuff.

I don’t think a shared stereo works in the work environment. The most obnoxious people will blast crap all the time. Music is a personal choice, not a group one. I worked in one place where they blasted horrible dance music or Stevie Wonder. Stevie is cool, but every day, all day? I used to unplug that stupid speaker whenever I had the chance. We were all trying to listen to our own headphones anyway, nobody cared to listen to the house music. 

The Gryphon Colosseum allows me to select from three bias levels but it does not slide between one or the other automatically. Medium bias is 70w Class A. I think vocals sound absolutely amazing on this amp. 

We live in good times. We’ve got great gear options and an easy way to stream a huge amount of music. 

@larrykell 

Coffee is another area that the masses could care less about. Give em Dunkin Donuts and they think they have the best. I used to take my own coffee on vacation & when we went to see family. I'm sure They thought I was a coffee snob. I'd offer them some but they just didn't get it since it didn't taste like theirs. I never did get into the expresso though. I don't really know enough about it

A big advantage of Class A amps is that by the standards of any AB amp they have a hugely overbuilt power supply and they can drive low impedance loads without faltering.

Yes they should have, but not all have, I’ve seen them with supplies that are close to saturation in the Class-A idle state, which means there’s nothing left for any Class-B transients, so they sound like a limp ****.

This amp I have here can do 3-100w user adjustable of pure Class-A, then to 180w Class-B, and it has the power supply to back it up, 5kva transformer with 300,000uf of supply caps. But it also weighs close to 60kg
https://ibb.co/Yp956yN
https://ibb.co/qW4qSc8
https://ibb.co/rdKwDgc

Cheers George