Super A - New Class A - Non Switching..

[Robert]

In the 70s and 80s many of the big Jap companies had amps using some form of sliding bias to give claimed class A perforance.

Was this simple spec chasing (0.001 % distortion etc etc) or do these systems have any real value in improving what we hear?

Seems every big amp used this trick in the output stage at one time and then it vanished. I used a number of big Technics amps with New Class A circuits and they performed well, but ran rather hot if I remember. The old Pioneer I have uses a variation on this theme and also runs very warm at low power.

Are there any sonic drawbacks with sliding bias?

Rob.

 

[prowla]

I thought class A was supposed to be technically better than class B.
However, Naim amps are class B and there's not much to beat them.
Hmmm...

 

[ghost123uk]

I'm glad someone has brought this up.
I use a pair of Tannoy Cheviots (HPD315 drivers)
They are very efficient speakers, which, of course, means that much of the time they are producing normal SPLs with only a watt or two of drive.
Now, a more usual AB type amp has a small percentage of crossover distortion at it's rated output.
However as the output is reduced in level, this percentage increases.
So with a pair of speakers requiring 45W, the crossover distortion is a very small percentage, but at point five of a Watt it is much higher.
SO - I spent some time trying lots of different amps (tho no were "hi end")
Result =
Most of the "AB" amps sounded fine at higher levels but grainy at lower levels.
Most of the "A" amps sounded much sweeter at lower levels.
A Technics SUV5 ("super A ?") sounded the best of the ones I had available to try, tho a JVC "A" was also very good.

Just my thoughts & findings.
Using the SUV5 for now.
Now where can I get a big pure "A" amp for hardly any money .....

JB - N.W. - UK