Yes you are right, I missed that bit..... The signal across R1 can be quite distorted, but the signal at J1's gate is always quite good. There is the problem though that it is only about 0.17V peak-peak. Perhaps the mod below would develop more output swing off J1's gate.
,---------------------------------------+--- 9V | | \ \ /2k /1k5 \ \ _|_ 0.15mA approx, | \_/ +--