Can voltage regulators develop crackling noises?

[omarvolta]

I have a Danelectro Cool Cat DC-1 Chorus that has this crackling noise when it's on. I checked the jacks(broken, replaced but the noise still there.) and pots (checked with different ones too and the noise didn't go away either.) and they were fine. I started probing with an audio probe and I could hear the crackling noise in the audio signal. Accidentally I touched the rail from the voltage regulator and the crackling noise was a lot louder. I lifted the Vout of the regulator from the board and checked the Vout again, and the crackling was there. There is no noise from the power supply or anywhere before the voltage regulator. The output voltage from the regulator is 12.3V(TL7812), so it's doing what it's supposed to do. But like it says in the title, can they develop this kind of noise(which is finding it's way into the audio signal path)?

[petemoore]

   Since the + is lifted, inserting a battery for circuit power will allow grading the chip supply system, batteries make the best dc in town.
  9v should allow circuit 'function' [if no 12v around] signal passing through, if it's cleaned up then something 'north' of the + must be causing it.

[andymac1962]

7812 (all 78xx & 79xx) regulators have noise on their output (500uV). This can be filtered with a small resistor (10 ohm) and large capacitor, say over 220uF.
LM317 type variable regulators have much less noise on their output (120uV), but these need two resistors to set their output voltage.

That said, for a guitar pedal it shouldnt make a lot of difference. Sounds like you may have a bad connection to a power supply filter capacitor. Check the AC & DC voltages at the input & output of the regulator. A high AC voltage on the regulator output may indicate a capacitor needs to be added / replaced.
Check all the solder joints,   may be as simple as that.
Also, it is good pactice to add a 0.1uF on input & output of 7812 regulators, to help with stability.

Replace those broken jacks, and double check all the offboard wiring is soldered correctly

[omarvolta]

Thanks for the replies guys!

   Since the + is lifted, inserting a battery for circuit power will allow grading the chip supply system, batteries make the best dc in town.
  9v should allow circuit 'function' [if no 12v around] signal passing through, if it's cleaned up then something 'north' of the + must be causing it.

I tried this and it cleaned up. Noise completely gone. Let me just say that there no hiss or hum, it's a crackling sound like when a pot is scratchy.  I'll now follow andymac's instructions and see if that helps with the regulator installed. I'll try a new regulator tomorrow.

[omarvolta]

Measured voltages. At the input I got: 18.2Vdc and 39Vac, and at the output: 12vdc and 25Vac.

[omarvolta]

Added more filtering as suggested above and no go. Returned it to stock, replaced 7812 and noise is gone. Thanks for the help!