120pf will make it seem "worse". Also the resistor values only give a VAS current of around 5ma which isn't very much. I suspect that Q4 characteristics are playing a big part here (assuming the passives are all correct of course).
I found an MJE350 works better as Q4 in a P3a. One thing though that the original design doesnt have, is some large decoupling (at least 220uF) on the power supply rails. I found that was necessary to ensure stability.
