It's class AB from Nelson Pass

[omishra]

Guys! Many wondered Mr NP always designed amps burning power to produce heat in fascination of class A amps. But environmentalist be happy, there is one class AB too.

Look at this - AB100 Class AB Power Amplifier - diyAudio

This look straight forward and I am not building one now.

 

[doors666]

you making boards?

 

[baswamin]

Oh boy, I have not even finished F5 V2 and now this shows up. I dont think I have any space left at home.

 

[longshanks]

Nelson Pass has been designing class AB amplifiers for many years.

 

[kroyin]

Actually the most logical thing to build after the V2T will be a 40-50 Watt Aleph X
(OM & Sachin ,I know I'm evil )
We can reuse the chassis Om can design the 4 fet PCB with same mounting specs as F5T

Well I have built and heard the F5 and Aleph J & like most NP followers me thinks AJ sounds better

 

[omishra]

Oh boy, I have not even finished F5 V2 and now this shows up. I dont think I have any space left at home.

I forgot to see bold - I am not building it now. If I take another amp job soon after F5T then I would be chased in woods.

 

[sann]

I am not building it now.

It would be interesting to see, how long you can hold yourself back Om.
Regards, sann

 

[anilva]

Nelson Pass has been designing class AB amplifiers for many years.

Why do you say that? He has always built class A Amps which work in Class AB after certain levels of power. His biasing has been in Class A. This is his first pure Class AB amp.

 

[longshanks]

Why do you say that? He has always built class A Amps which work in Class AB after certain levels of power.

I always thought an amplifier which works in class AB when it goes beyond its class A power region is supposed to be class AB amplifier and not class A amplifier, i could be wrong.

AFAIK, pass product catalog has always had the X series which are Class AB,XA series which are Class A up to 4 ohms loads, and the new XS series which they say is an improvement over XA.

For example lets say an amplifier works in Class A say till 25 watts but its rated output is 75 watts @ 8 ohm, when this amp is connected to a speaker the power delivery is very dynamic depending upon the speaker efficiency,the music being played and Impedance drop.Considering this fact these Class A design which switches to Class AB wont work in Class A most of the times unless it is a true class A design like the ones made by gryphon and a few other manufacturer where the power doubles in Class A up to .5 ohms.

Again i am not an expert, in fact i know nothing much about how these amplifiers work but this is what i understand from certain people and by reading,if there is a different explanation then do let me know and i shall learn.