Hi! In an echo unit i made, two of the pots (the dry & wet) make a dusty noise. But there is no dust.. I replaced them with new ones, and have the same issue. The power supply is a transformer audio power supply so there is no noise from threre. the chassis is also grounded. Also test the unit in a guitar amp and to a monitor speaker, results are the same. Any ideas?
Not sure from your words what the circuit is? What is "dusty" noise?!
However, if there is rustling noise generated when the pot is turned, the most obvious cause is DC flowing through the pot.
You need to show the circuit you are using. A simple cure would be to ad a cap in series with one end of the pot (like 10uF ?!) but this may not work if the current is needed to bias something. This is just bad design!
Post the circuit!
EDIT: added that if there is already a series cap, it may be leaky!
However, if there is rustling noise generated when the pot is turned, the most obvious cause is DC flowing through the pot.
You need to show the circuit you are using. A simple cure would be to ad a cap in series with one end of the pot (like 10uF ?!) but this may not work if the current is needed to bias something. This is just bad design!
Post the circuit!
EDIT: added that if there is already a series cap, it may be leaky!
Last edited:
it's the same noise you get from pot with rust or dust inside. This is not the first time I make this circuit,but it's the first time I have this problem. It's almost the same circuit: http://www.valvewizard.co.uk/smalltimeschem.jpg
but i use also a pot to dry signal, and the wet pot (in link as "mix") it's not grounded it's 4.5V (vcc/2 voltage reference)
but i use also a pot to dry signal, and the wet pot (in link as "mix") it's not grounded it's 4.5V (vcc/2 voltage reference)
no don't rewire or jumper things. the 4.5V is considered ground AC ground./
use a handheld DMM on DC checking the potential across any pot. use one probe on fixed at 4.5V and using other probe check any pot terminals voltages greater than zero.
If the mentioned noise is only present while adjusting the potentiometer, is this correct.
In this case you must replace all electrolytic capacitors to the inputs of potentiometer by a foil version (e. g. WIMA MKS).
Yes. This is precisely the symptom you should expect from DC on a pot: noise when adjusting it. In addition, the pot is likely to age more quickly and get to the stage where it is noisy all the time as well.tiefbassuebertr said:
In non-critical situations an electrolytic is good enough. Low voltage circuit for a guitar amp etc. is a non-critical situation.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.