Fractal Audio has a total of 3 Brownface Fender amps : a 6G12 Concert, a 6G4 Super, and a 6G11 VibroLux!!
https://wiki.fractalaudio.com/wiki/index.php?title=Amplifier_models_list
Clearly the Quad Cortex NEEDS AT LEAST ONE friggin Brownface, ok?!
Can you please add a profile of a Blonde Showman (6G14-A) to the Quad Cortex? Any other Brownface/Blonde amp with two, or four, 6L6’s will do but it MUST have a “Presence” knob!!! The “Bright” channel on the Vibroverb has wayyy too much presence/brightness in my opinion; I really think a “presence” knob is needed to reign in the brightness on these. Also, if you have a choice between tube rectifier or solid state rectifier, I would prefer that you model an amp with a solid state rectifier.
Please and thank you!
Be cautious, sometimes old things that are pristine are that way because they were never used. Might be a good idea to understand why.
Presence on Fender amps cut highs from the negative feedback loop around the power amp which increase brightness in the power amp. That is, presence can’t cut highs in a Fender amp, only increase them.
That’s not the case with a Mesa Boogie Lone Star though, that Presence control is a high cut (or low pass) filter between the preamp and power amp that is used to cut spikes from the preamp distortion. This presence control does operate as you described.
Best option is to turn that bright switch off. Some Fender amps have the bright cap hard-wired without a switch. A common mod is to clip the cap to tame the brightness, especially when using the amp with pedals.