Lead Solder Buzz
- Thread starter jimilee
- Start date
comradehoser
Well-known member
I know it's dumb, but make sure they are the right parts in the right places? I was totally stumped on a really complicated build until I realized that I had used TL071 instead of TL022. Also *convinced* that Q3 in my failed marigold build was PNP... it was not. The correct NPN substitution unfailed it well.
jimilee
Well-known member
Yep, I had my resistor calculator out and everything.
jimilee
Well-known member
Stompbox parts. I tried some known good 4558s also. Same noise.
comradehoser
Well-known member
Help me, audio probe kenobi, you're my only hope
andrewsrea
New member
It sounds to me like the charge pump (IC4) could be the culprit. I've experiences similar effects before. Make sure C101, C100 and C102 are all oriented correctly (cathode negative facing the switch). Also, note that not all 1044's or 7660's are the same. The last few letters make a difference and some buzz like that. I use ICL7660CPAZ which are affordably available, reliable and don't leave 'switching supply chatter' artifacts.
If you have access to an oscilloscope, check pin 8 of IC4 (VCC) for a saw tooth oscillation in the 90Hz range. If you socket your ICs, pull IC4 and see if it goes away (you will still have 9V at VCC, but the other IC's will be unbalanced and may not sound good, as this design does not us a V ref). Check all components for orientation (IC's and electrolytic caps).
Additionally, mine like other builders who commented, had annoying hiss and oscillations (like 200Hz to 500Hz 'whistles'). Fixed by changing C8 to 220pF and R10 to 510K, which you can read about here: https://forum.pedalpcb.com/threads/lead-solder-overdrive.20717/page-2#post-278621.
Hope this resolves your problem.
If you have access to an oscilloscope, check pin 8 of IC4 (VCC) for a saw tooth oscillation in the 90Hz range. If you socket your ICs, pull IC4 and see if it goes away (you will still have 9V at VCC, but the other IC's will be unbalanced and may not sound good, as this design does not us a V ref). Check all components for orientation (IC's and electrolytic caps).
Additionally, mine like other builders who commented, had annoying hiss and oscillations (like 200Hz to 500Hz 'whistles'). Fixed by changing C8 to 220pF and R10 to 510K, which you can read about here: https://forum.pedalpcb.com/threads/lead-solder-overdrive.20717/page-2#post-278621.
Hope this resolves your problem.
