Pronounced low freq sag

[will]

Hi,

One of my favorite distortion circuits has a pronounced sag at full gain when I hit a low frequency note/chord. Noticeable below A on the E string with my strat at full volume. I’m wondering if it caused by temporarily re-biasing the input. The circuit does limit the bias current for the gain transistors. The circuit does take about 10 seconds to stabilize for full volume once turned on. Similar to a tube circuit. I suspect if I use a smaller input cap to roll off more bass on input. It would reduce this effect.

Just wondering if this is what happens with a tube rectifier?

Is this normal for a compressor?  

Comments?

Regards,
Will