I’m holding an E4, then sweeping the filter:
osc 1 + 2 are set to none, filter cut is 0 to start/end, res is 0 for the first sweep, then 63 for the second.
Does it sound like I might have a cold joint on a ground connection somewhere, perhaps? I’ve checked the joints and they look okay to me (who knows what that means)
This is not normal. Try a different power supply, and to be on the safe side, a 9V battery connected with a battery clip.
This was discussed elsewhere but the only noise there should be is digital noise at ~ -68dB below the signal.
Two swapped resistor values on the filter board might explain the very low signal. If you have a scope check that the pp output level is at least above 500mA.