Black AMP gets better

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by BarryT, Jul 23, 2022.

  1. BarryT

    BarryT MOT: Austin Audio Works

    Pyrate
    Joined:
    Feb 8, 2021
    Likes Received:
    425
    Trophy Points:
    53
    Location:
    Austin, Texas
    Home Page:
    A short note on my work on the Black AMP. While working on the technology of auto-transformer based volume (level) controls and the philosophy of their operation along with resulting better performance than voltage dividing potentiometers I had an epiphany as to how this thinking could be applied to the Black AMP. Could I keep the feature of the volume control and bypass its sonic issues? This would directly apply to the higher power versions (if it works I will modify the prototype of the 50-watt Concept AMP built a while back.

    After a week of playing with simulations, searching my old and cluttered memory, and reading up more on current mirror theory I got an idea which last night I completed a working model of.

    It worked, I could alter the current gain-stage of the AMP creating an adjustable gain with a variable resistance with a range of +20 to -50 dB that did not alter the amplifier's performance. Distortion did not change with gain level (still had the same even-only harmonic distortion at all frequencies), bandwidth did not change, none of the properties of the amplifier changed but the gain. The gain could be changed without stability issues by one resistor, not two as in a voltage divider as used in feedback circuits. Thus there is no 'Information Entropy' as displayed in standard voltage dividing networks. I went to bed happy.

    I am now altering a Standard Black AMP into this new topology for listening and will run it by my helping 'ears' for critical evaluation before I decide to change more. I think I found a way to get auto-transformer performance without the auto-transformer.

    --
    Barry
     
    • Like Like x 9
    • Epic Epic x 3
    • List

Share This Page