So, I have been building this same circuit, a number of ways (see circuit here:https://www.electronicspoint.com/forums/threads/a-stretch.293212/

I used a LM741 op amp and it worked. Did the same circuit, this time incorporating an additional resistor as suggested by AudioGuru- and it worked.

Now I built it using the 4558D op amp. It worked but then when i tried it the next day, it did not. I found that the voltage was not being properly divided by the voltage divider. I found a faulty resistor and replaced it (one of the 10 K ones R33)

Tested it and it indeed dropped the voltage to roughly 4.5 volts. But minutes later, it went back to close to 9 volts. How can that be?

I used a LM741 op amp and it worked. Did the same circuit, this time incorporating an additional resistor as suggested by AudioGuru- and it worked.

Now I built it using the 4558D op amp. It worked but then when i tried it the next day, it did not. I found that the voltage was not being properly divided by the voltage divider. I found a faulty resistor and replaced it (one of the 10 K ones R33)

Tested it and it indeed dropped the voltage to roughly 4.5 volts. But minutes later, it went back to close to 9 volts. How can that be?

Last edited by a moderator: