So you should be the one answering this topic
I suppose you're right.
When it comes to gain and overall voicing, the AD50 and Retro 50 are really quite similar. They're both capable of bold, gutsy cleans at low to moderate volume and and growly overdrive at higher volume levels. The differences in the EQ just allow for accentuating different frequencies.
The presence control on the AD50 allows for controlling the highest of the treble frequencies, and can come in handy if you want to get a sharper attack or dial out some sizzle. When the foot switch is engaged, the bass and treble controls of the AD50 are bypassed, but the presence control is not.
The middle control on the Retro 50 just allows for greater control of the overall EQ shape, specifically in regards to the relationship between the mids and the other frequencies. There is some overlap in the ranges of the controls, so they interact with one another. When the foot switch is engaged, all three EQ controls of the Retro 50 are bypassed.
The EQ controls on the AD50 and Retro 50 are passive. Each EQ knob on these amps is like a passive volume control for a particular band of frequencies. The EQ controls cannot boost the signal, but can only lower the level of their band of frequencies. When the foot switch is engaged, the EQ is bypassed, and the "boost" that occurs as a result is really just the result of re-routing the signal around what would "cut" certain frequencies.