I have spent the last few days trying to prototype a TL082 electret mic preamp (based on this schematic). I swapped the TL071 in the linked example with TL082 (which I understand to be more noise-prone but otherwise similar), made the appropriate changes to the wiring (VCC moved to Pin 8, signal output moved to Pin 1, etc.) and am using 50 Ohm resistors for the Voltage Divider (as opposed to the 62 Ohm used in the example schematic) but otherwise my circuit is identical (this was laid out in EAGLE and the PCB cut via CNC, BTW). See below for my schematic.
As far as I can tell the preamp is sort of working but I am struggling to test and diagnose it. For example: an LM386 power amp will not amplify the signal from this TL082 circuit. The LM386 circuit I use for most things will not amplify the signal from the pre at all (no sound comes out). No idea why, here's a schematic of that circuit below:
If I plug the TL082 into a different amplifier, say a honeytone (which uses the TDA7052A IC), I can kind of hear the signal, whereas I get nothing through the LM386.
Does anyone see anything wrong with my TL082 schematic? Should I not be using LM386 to amplify this preamplified signal? Would something else be better? Any suggestions or reccs would be greatly appreciated!
Best Answer
Figure 1. Inverting mode amplifier with no Ri.
Also R3 would normally be connected to ground to discharge C1 and prevent pops when plugging in. As it is it will maximise pops.