Older receivers with class A

I collect older units, wondering is their any difference between Denons non switching class A, from the earlier 80s, and their later Optical class A, from the late 80s early 90s, Thanks.
Not an Audiophile, just a dude who loves music, and decent gear to hear it with.

Comments

  • invalid
    invalid Posts: 1,373
    Optical class a is a variable bias, plain old class a bias is biased at full tilt no matter if no signal is going into the amplifier. These bias schemes were designed to use less energy and produce less heat if you weren't listening loud. Some people claim that they don't sound quite as good.
  • JayMX
    JayMX Posts: 446
    I picked up a like new condition Denon PMA-980R a while back and it really surprised me. An excellent unit with the “optical class A” circuitry under the hood. It is very, very good.
    A couple photos with comments here:
    https://forum.polkaudio.com/discussion/191620/denon-pma-980r-anyone-have-experience
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (4x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.