Duocast Help! Crackling/static?

Dan0h

Well-known member
So I’ve had this issue since the completion of the build and it’s really “driving” me crazy, pretty much to the point were I stopped using the high gain side of the pedal which sucks because I like that sound as much as I like the low gain side. I’ll do my best to describe it. There is an almost static crackle broken speaker nasty overtone that happens when I really dig into the strings while on the high gain side of the Duocast only in 18v mode. I’ve turned down the trim gain lvl and it helps and when I roll my strat volume knob down to 8 or less it goes away completely but I really want to utilize the amazing sound of my volume at ten without having that overtone crackling occurring. Does anyone know what it could be? Maybe a bad transistor? But it sounds amazing at all the other settings. I also have heard this strange crackle static on the Coda Black hole build I did but it’s no where as prominent as my Duocast. Any thoughts would be highly appreciated. I have tried to record this noise and just can’t seem to capture it. It’s some what random but too often at the same time. HELP. I used all the build doc parts even paying up for the OC71.
 

Betty Wont

Active member
I luckily socketed them so I will give that a try. I have very limited pnps on hand but if the crackle goes away then that means the one I currently have installed is bad right?
Doesn't necessarily mean its bad, just that you don't care for it. Germaniums often benefit from auditioning. Your BC549 could affect your issue as well.
 

Dan0h

Well-known member
Doesn't necessarily mean its bad, just that you don't care for it. Germaniums often benefit from auditioning. Your BC549 could affect your issue as well.
Makes sense. I really hesitate to swap them because the sound I get is absolute magic. It’s just the top end of the gain is no good. I’ll give it a try tonight and see what happens.
 

mikealbert

New member
Were you ever able to get this sorted out? I'm hearing a similar response with my Duocast build I just completed. I have Q1 (BC549) and Q2 (AC128) socketed and thinking I might try swapping them out.
 

Dan0h

Well-known member
Were you ever able to get this sorted out? I'm hearing a similar response with my Duocast build I just completed. I have Q1 (BC549) and Q2 (AC128) socketed and thinking I might try swapping them out.
I recently swapped out my bc549 and it sounds better. But the crackle is still there on the heavy channel. I’m pretty sure it’s the oc71 when high gain is applied to it. I have contemplated ordering another one but that $10 price is nuts. I wish I had some friends in the UK because they seem to be more available over there.
 

Dan0h

Well-known member
Were you ever able to get this sorted out? I'm hearing a similar response with my Duocast build I just completed. I have Q1 (BC549) and Q2 (AC128) socketed and thinking I might try swapping them out.

BC407B is what I swapped the 459 for. Sounds delicious.​

 

Dan0h

Well-known member
After trying multiple combos I have come to the realization that the oc71 is the magic sound I want in this pedal but I may just have a funky one ( the crackle at high gain) so I bit the bullet and ordered a couple more to try out. I also wanted to try my luck at bread boarding a pedal taking my favorite sections of pedals I really like and trying to meld them into one perfect, for me, pedal. The extra oc71 will be a part of that.
 

Dan0h

Well-known member
Well this is a bummer, I picked up two additional OC71's tried them both and the crackle is still there. So Its not coming from the transistors could a crackle come from the transformer, a diode, a cap? This is going to drive me crazy trying to find this crackle. I love this pedal so much I just want to be able to crank the drive without the crackle. Any thoughts?

I guess the good news is now I have two really cool sounding OC71's to find a build for.
 

caiofilipini

Well-known member
Well this is a bummer, I picked up two additional OC71's tried them both and the crackle is still there. So Its not coming from the transistors could a crackle come from the transformer, a diode, a cap? This is going to drive me crazy trying to find this crackle. I love this pedal so much I just want to be able to crank the drive without the crackle. Any thoughts?

I guess the good news is now I have two really cool sounding OC71's to find a build for.
I used two OC71s in a Tone Bender MKI I breadboarded earlier this week and it sounded killer!
 

music6000

Well-known member
Well this is a bummer, I picked up two additional OC71's tried them both and the crackle is still there. So Its not coming from the transistors could a crackle come from the transformer, a diode, a cap? This is going to drive me crazy trying to find this crackle. I love this pedal so much I just want to be able to crank the drive without the crackle. Any thoughts?

I guess the good news is now I have two really cool sounding OC71's to find a build for.
Have you got some Contact Cleaner, lift the Dust cap off Level 2 Pot & spray while rotating to see if there maybe debris on the wiper that is causing
your Issue. You may have a bad Pot!
Also check your Level 2 Footswitch wiring for bad joint!
 

PJS

Member
Crackle can indicate a bad/cold solder joint. Can be a bad connection between a component and a socket also. Check all your solder. Try an audio probe and see if you can find where the crackle originates.
 

Dan0h

Well-known member
Have you got some Contact Cleaner, lift the Dust cap off Level 2 Pot & spray while rotating to see if there maybe debris on the wiper that is causing
your Issue. You may have a bad Pot!
Also check your Level 2 Footswitch wiring for bad joint!
Very cool. Did not think about these and will do them.
 

Dan0h

Well-known member
Crackle can indicate a bad/cold solder joint. Can be a bad connection between a component and a socket also. Check all your solder. Try an audio probe and see if you can find where the crackle originates.
Thank you. I will do that.
 
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