Thanks Wilkie I’ve learnt something I was trying to figure out why Colin was getting 66K resistance between pins 6 and 7 using the schematic I thought those 22Ks R12, 13 and 14 aren’t in parallel so why’s it 66K? Paralell connections always throw me
I’ve just looked again and see R13 is actually a 68K in reality, so the 66K is about right
I did read the notes honest!
Colin you can use any dual op amp to test 4558, NE5532 etc doesn’t need to be a TL072 to test it