Your new peak detector has its output reference voltage at half the supply voltage which is not compatible with the LM3915 that needs it at ground.
It does not have the current-boosting transistor at the output of the opamp so it might not charge the capacitor fast enough for high frequencies.
The output of the opamp will suddenly go as low as it can for each negative half-cycle of the input and the delay for it to come back up to normal ruins it at high frequencies, it is missing a second diode to prevent its output from going too low. The 100k at the output should be 330k for good low frequency detection.
Why does your 'scope show one frequency but "says" two frequencies?
It does not have the current-boosting transistor at the output of the opamp so it might not charge the capacitor fast enough for high frequencies.
The output of the opamp will suddenly go as low as it can for each negative half-cycle of the input and the delay for it to come back up to normal ruins it at high frequencies, it is missing a second diode to prevent its output from going too low. The 100k at the output should be 330k for good low frequency detection.
Why does your 'scope show one frequency but "says" two frequencies?