Hi,
i also did the same simulation (i wasn’t aware of geshsoft ones) as geshsoft but with TINA-TI (Texas Instruments). And looking at the simulations i came with the same conclusions. Getting rid of C9, C11 & C73 (or at least use lower capacities) will improve the circuit performance. Also the use of small valued resistors (i.e. 2,7k instead of 27k and keeping the same ratio for others) will also improve bandwith (but that’s a few small resistors -16- to solder).
That said, the only fact that disturbs me from simulation is that i didn’t find the strange channel behaviour venarim described. I suppose this is due to the stray capacitances not modelled in simulator. Sooo, it would be interesting to know how accurate are this simple simulations in order to tweak the circuit.
I leave the circuit as an attachment just in case someone wants to play with it.
QUAD.zip (7.86 KB)