But I didn't add another driver transistor unless you are referring to the use of the MJ11016 darlington output transistor. I did try the circuit with a 2N5668 and it had the same output problems. The original design used a 100uf cap at the output. Initially I thought this was too high and changed this to 10uf like the other design when I had oscillations I changed it back to 100uf, but now it seems I was heading in the wrong direction and need to change it back to 10uf. It seems having a slow output tranistor with a fast opamp can be an issue. So would using a faster power transistor help? If so, how do I choose a faster transistor from the data sheet, by the bandwidth product? a 2N3055 is listed at 6MHz, but a 2N3442G is listed at 80mHz. Would that help? I added a 100k resistor to the base of the MJ11016 power transistor and the oscillations did stop. I will change the 100uf cap back to 10uf . I didn't like the response on the current control and the setup with the led connected directly to the output of the opamp concerns me. It seems this indicator should be driven by a transistor. I noticed that when the inverting pin was higher than the non inverting pin the output voltage on Pin 6 would slowly decrease (over seconds) instead of nearly instant control. I may need to change C4 to 100pf instead of 220nf but I don't see that as a total fix becasue of how slow it is responding.