Just looking at my V divider of 2 x 47k strung across -/+.
My measurement from ground to divider junction indicates 4.42v from Gnd. the, battery measures 8.94v.
Connecting a 1m resistor to that brings it to about 1/4 supply voltage, or 2.02v.
This Is a new board I built yesterday, and have been debugging ever since I shelved the Dist+ with the LM386 Vdivider.
The 'LM386 supplied' Dist+ also has 2.02v shown on opamp pin 3.
I bought some more lm741's. the readings from one opamp to the next vary only slightly.
I added a 470k to the 1meg, in paralled this brings the voltage up to 3.3v, still not optimally biased.
I don't believe it but expect you to, I'm only showing the exact experiment repeated, repeated earlier experiments with many DIST+'s and the "LM386 Supplied" one that decided to exhibit the odd behavior.
I posted earlier the voltages, they are all quite nice enough for govt. work, ~1/2v are at the opamps _input and output, Gnd. is 0v at pin4, pin7 is V+
1
2 2.02v
3 4.24v
4 0v
5
6 4.36v
7 8.94.
8
Everything is connected correcly except my spelling on correctly, :icon_redface: two builds in a row prove this wrong.
Why do 1megs directly from, and only from 1/2v convert to 1/4v ?
It's likely that your measurement meter is loading down the voltage through the 1K.
It is common for this to be a problem.
I'm not sure I understand, the DIST+ has no 1k.
This would be the first for not being able to use voltage measurements of OA pins to debug, also the circuit isn't functioning.
Sorry - I meant the 1M bias resistor.
This is strange sound to me, I remember being able to bias [IIRC] Dist+'s and read the voltages on the pins.
And it seems this pin is where the signal isn't 'going in', as there is no 'click' on pin 3, pin 2 has an 'amplified a little' click, and the output has a click similar to farther toward output of the circuit/the amps plug tip.
So although I can understand how a 1meg could 'screw' with the meter, [not how that would] and show a false reading, I'll go mess with it again and make sure if it's not working.
It is working just fine.
I messed about for times, then tried the Ohter new Opamp, good thing I bought two, fired right up. Wierd as anything. I guess my little DMM doesn't like reading voltages through big resistors, otherwise the opamp sounds biased, I guess you Cant always trust the DMM.
A slight increase to .022uf input cap, also 1uf [instead of 10] output, seemed bassy enough, .1uf though 'starved' it a bit.