ANALOG SEEKrets (DC to daylight) is a text book for senior under-graduate electronics designers and final-year physics students taking an electronics option. It will also be useful to recent graduates who seek increased skill in the field of electronics design. Even seasoned “digital engineers” will benefit from the analog insights presented in this book.
It is common to use a potentiometer in the feedback loop of an opamp to adjust the gain of a booster or distortion pedal. The Rat and TS-808 types (and many others) use this method of adjusting the gain (or drive) to control the amount of distortion.
The LM4562 is an excellent dual opamp with very low noise and distortion. Its performance is tough to beat for audio use.
However, it appears that the chip is easily damaged. I have blown up 2 of them in the past few months, and prior to that, it has been more than 25 years since I last trashed a bipolar or jfet opamp. Also, I have had reports from a few project builders using my pc boards that have tried the LM4562 and also ended up with fried opamps.
You must not apply reverse power voltage or it is toast. Don’t short the output. Also, handle with care, as you would a mosfet chip. Observe these few precautions and you should have good luck with the chip. I use one in my DIY function generator with excellent results, and another for its low noise/distortion in a brickwall filter.
If you are using the LM4562, and your project is not working, sub in a TL072 or 4558 temporarily and see if that fixes it. If so, you might be better off using a 5532 or a fresh LM4562 that has been carefully handled.