push pull Vs single ended class A amp

[space2000]

hi,

i have read about class A amp. i undestand that single ended class A amp have less efficiency then Push pull class A.

which sound more sonic? Push pull or single ended?

thank you
michael

[Workhorse]

Go for Balanced single ended with active current source loading Class-A using mosfets.

[lineup]

Originally posted by Workhorse
Go for Balanced single ended with active current source loading Class-A using mosfets.

I would go for class A push-pull mosfet ( like IRFP240 / IRFP9240 )

If we look at Nelson Pass ... the mosfet guru of this forum
he started out with Single Ended resistor loaded MOSFETs ( balanced )

But later on, he has frequently used PUSH-PULL Class-A.
Like for example in his F4 amplifier,
which is a schoolbook example how to make a very good Class A output

http://www.firstwatt.com/products/f4.htm

F4 ... A Power Buffer:

Like everything else from www.firstwatt.com it is a unique amplifier.

It has
- no feedback and
- no voltage gain,
- only current gain.

[Workhorse]

I have my own taste of balanced single ended in class-A using all N-channel mosfets[no p-channel crap]I dont like complementary mosfets, because they are not complementary in reality due to vast difference in specs.

Even all my class-AB and Class-H amps also feature All N-channel output stage only

[Wavebourn]

Push-pull is the way to save an electricity.

[Workhorse]

If you really want to save the energy then go for Class-D.

[djk]

Why not try push-pull class A from ±12V rails and run class G with ±50V rails?

[Wavebourn]

Originally posted by Workhorse
If you really want to save the energy then go for Class-D.

A+C+C is close to class D, and is the best compromise between power consumption and sound quality I ever found. Imagine 5-bit D/A converter where each bit is also analog...

[Workhorse]

Originally posted by djk
Why not try push-pull class A from ±12V rails and run class G with ±50V rails?

Great........

[djk]

"A+C+C is close to class D, and is the best compromise between power consumption and sound quality I ever found. "

I would tend to agree, what I am calling A+G is what you would call A+C.

AB+C+C is how the original Carver Cube (M400) ran; ±25V, ±50V, ±80V. The lowest voltage and size of the heatsink (none!) prevented higher than AB bias. Efficiency on a resistive load was about 87.5% (as analyzed by Hsu when he was at MIT), and improved driving a reactive load line.

Most people don't need 80V rails, 50V rails may be adequate for all but the largest rooms or most inefficient speakers (it is only about 3dB less in any event).

±12V biased to about 1A would allow about 10W in class A (6R nominal) before transitioning to the higher rails. For average listening the amplifier may never leave class A, and would still have 10dB of headroom for demanding program material.

The 25W of bias would require about a 1°C heatsink for low temperatures, but this is no worse than what a typical 100W class AB would need (and 25W is what the 100W Hafler DH200 ran for bias, but only would deliver 0.5W/6R in class A).