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.
hehe, perhaps it's better idea to stick to your topology. There were some variations that used two diodes. I suppose it would be possible to add current-boosting transistor but dunno.
How would tlo71 be hooked with split supply? split supply is quite new for me, surprise....
that i know, artificial ground can be made with two resistors and opamp as buffer, and some more better topologies...
Why does your 'scope show one frequency but "says" two frequencies?
hmm, good point, haven't noticed that before, mostly i measure only one frequency so i really didn't notice that one before...But, i tested that again, and it has same frequency, around ~92hz for both, maybe single-shot blew it up somehow or then there was trigger issue. I'll try to keep an eye out for that one, thanks!
yeah, farnell and TME have quite difference in price for TLE214x, i'm not buying these, untils as last resort.....
Snow felled here too, first snow actually for this winter.....and 20cm, there were, still are quite many households without electricity.