Bobs Cordell's Super Gainclone LM3886 - trying to simplify

Member
Joined 2011
Paid Member
Hello all,

I am having this idea to simplify the original Cordell's Super Gainclone schematics. In particular, I want to get rid of servo circuit and add capacitor instead.

Attached are the original schematics from the book, my version, and LTSpice simulation file.

Any comments are welcome.
 

Attachments

  • sgc_from_book.jpg
    sgc_from_book.jpg
    49 KB · Views: 320
  • sch.PNG
    sch.PNG
    14.5 KB · Views: 291
  • LM3886-super-gainclone.asc
    LM3886-super-gainclone.asc
    5.3 KB · Views: 122
  • Model.zip
    Model.zip
    3.3 KB · Views: 129
  • ne5532.zip
    ne5532.zip
    745 bytes · Views: 121
You can put a ~22uF cap in series with R9 (1k) (R2 in simulation) and drop the servo (and drop U10 (U8 sim)). It's possible a ~20K to ground (+ cap?) on the positive input (pin 10) may improve the offset. There is a DIYA thread (~LTC Spice) about bad spice models of the LM3886. I think that model has a nasty phase inversion when overdriven but it's OK if you stay below clipping. C4 (C3 sim) worries me but whatever works?

Pushing the loop gain on chip-amps is the main reason they fail, so I'm not fond of the "super gain" idea. More than once, I have found that a chip-amp can sound very good if you back off the feedback.
 
Last edited: