You probably want to decrease the value of C41 - stock, it's 470pF, and it forms a lowpass filter with a corner freq of ~3.4KHz (encroaches on your treble a bit). I dropped it to 390pF, which moves the corner freq. up to 4KHz, which is kind of my upper-end preference for drive circuits that are intended to be on the gainier side (and lots of speakers for our purposes tend to start rolling off the treble around that freq. anyway). ...If you prefer more "air," and you'll be keeping the gain/drive low on the lead channel, you might want to make C41 even smaller. Using a value of 330pF will move the corner freq. up to ~4.8KHz. IMO, it's worth taking the time to tweak the value and corner freq., because there's a clipping circuit at this point (it's the second of two), so you can somewhat finesse the harmonic content "right at the source."