New error correction amp

[PMA]

Here are some new measurement results of the 'revived' PM-AB1 amplifier. Distortion is measured close to clipping, at 25W/4ohm.

 

[Bigun]

Wow, those results look really impressive. I may have to revive my thoughts on making a hubrid tube + buffer using this idea for a buffer - although the input impedance will need to be low enough.

 

[tiefbassuebertr]

Inspired by NP in a "Hawksford" thread, I have developed a new error correction circuit. The schematic of working amp is attached. I have been testing it for more than a month (both measuring and listening) and results seem to be promising.

Are there commercial amps, where this kind of error correction is in use ?

Hi, AKSA,

I found this arrangement of ML-33, it is advertised as a "non-turnoff" biasing scheme.

Is it really do not turn off?

There is a hard borderline between different load impedance concerning the THD+N character (fundamental notched out) - go to fig. 4 and 5 under
Mark Levinson No.33H monoblock power amplifier Measurements part 2 | Stereophile.com
8 ohms looks good, but after lowering the load impedance to 2 ohms and keeping the output voltage constant, resulting in 200W dissipation in the load, brought up both the level of second-harmonic distortion and the converting of character from sine wave to triangle/saw tooth character, as is shown in fig.5.