Sovtek mig 100 too bright need more lows

[Modelmonster]

Hello
I just picked up a mig 100 and though it sounds really good it is very bright.
I clipped the bright cap on the low input (which helped a bit).
But still very bright (and not sure if this is the best way to add more bass)
Any ideas?
here is a link to schematic
https://music-electronics-forum.com/for ... ic-request
Thank you all in advance