SOLVED Angry Andy's hisssssss?
- Thread starter pgodfrin
- Start date
chongmagic
Well-known member
Can you post some pics of the front and back of the board? And also the offboard wiring.
Chuck D. Bones
Circuit Wizard
And do it on the Troubleshooting forum. This is Build Reports.
chongmagic
Well-known member
Yeah didn't notice that, you'll get more help there.
Nostradoomus
Well-known member
Shorten up your wiring as much as you can to start with. If you have enough lead try twisting the two wires from your DC jack together. I’d also sand down the paint where your in/out jacks make contact on the inside of the enclosure.
Is it only hissing with a battery or power supply as well? How much hiss are we talking? It is a gain pedal after all
Is it only hissing with a battery or power supply as well? How much hiss are we talking? It is a gain pedal after all
Chuck D. Bones
Circuit Wizard
Nostradoomus beat me to the punch. Sand off some of the paint around the jacks, switches and pot holes (on the inside of the box). All of those parts should be making electrical contact with the chassis.
What you are hearing as hiss may be ultrasonic squealing. Long wires on the pots can cause problems. You really should be using board-mounted pots.
You also need to clean the board. Am I right in thinking this is your first build?
What you are hearing as hiss may be ultrasonic squealing. Long wires on the pots can cause problems. You really should be using board-mounted pots.
You also need to clean the board. Am I right in thinking this is your first build?
pgodfrin
Member
Yeah so it hisses on battery and power supply (albeit a crappy one). And hisses with the guitar pots up and down. But I did clean the pcb with IPA (it hissed before and after cleaning) and this is not my first build. I don't like using pcb mounted pots as I like to put the pots wherever I want to. The leads from the 9mm pots are about 1.5 inches of 24 awg. None of my other builds hissed like this, which is definitely p-hissing me off (lol!). I'm curious about sanding the contacts on the enclosure - never needed to do that before - I'll definitely look closer at that...
Chuck D. Bones
Circuit Wizard
That would kill the signal at the input, which affects the signal/noise ratio, but should not be the cause of the hiss. JHS copied the M I Audio Crunch Box and added a diode switch. I have a cheap Chinese knock-off of the Crunch Box (Joyo Deluxe Crunch) and it is very quiet. With the DRIVE dimed and VOLUME at unity (about 9:00), the hiss is barely audible and it's way below the pickup hum. Once you get those resistors changed, see if the hiss is still there. I'll bet it is. You probably have a noisy component. This pedal has 80dB of gain when DRIVE is all the way up, so even a little noise in the first stage gets magnified 10,000x. You can try swapping opamps. LM833s are supposed to be quiet. My money is on C3 & C6. Disk ceramic caps are known to be noisy and microphonic. You'd be better off with film, MLCC or my favorite: silver mica.
