Hello!
I recently built a silicon Tonebender MkII circuit: http://tagboardeffects.blogspot.com/2013/07/npn-si-tonebender-mkii.html (http://tagboardeffects.blogspot.com/2013/07/npn-si-tonebender-mkii.html) Transistors are three 2N2369's measuring 60-70 hFE. The only changes I made to the circuit were to the diode (1N4002 instead of 1N5817) and a 10K linear bias pot instead of the 5.6k resistor on Q3. For the offboard wiring I used this layout: http://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html (http://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html)
The fuzz works beautifully, but I'm getting a lot of background noise when it's plugged into AC adapters. My single cord adapter yields a consistent hum, while my cheap daisy chain adapter creates a siren sound. The siren noise increases frequency when I connect other pedals to the daisy chain. It gets louder with more volume and gain (naturally). Changing the bias doesn't affect the noise.
Here's a clip of the siren noise: https://www.aronnelson.com/DIYFiles/up/2021_06_21_10_34_52.mp3
Below are a few pics of the build for reference. My wiring connections appear to be OK (albeit messy) and I don't have any solder bridges on the vero board. When I disconnect the power cord and run it off a battery, the background noise goes away.
Since I'm new to this, I'm not sure how to start troubleshooting. Are there specific issues that I should look for, or possibly mods to the circuit that will fix the noise issue? Any help would be greatly appreciated.
Thanks!
(https://i.postimg.cc/dZB22d2q/IMG-20210621-103716045-HDR.jpg) (https://postimg.cc/dZB22d2q)
(https://i.postimg.cc/2V0JmLsR/IMG-20210610-001110875.jpg) (https://postimg.cc/2V0JmLsR)
(https://i.postimg.cc/Sn5vYFQg/IMG-20210610-001123738.jpg) (https://postimg.cc/Sn5vYFQg)
without a circuit diagram ..... I'd say easiest thing to try is to lift the K end of D1 from the board and solder a resistor - 100R ~ 470R - from the K to the hole it vacated. this will form an RC supply filter, might knock out some hash.
Thanks! To confirm, you're talking about this end of the diode, right?
(https://i.postimg.cc/bdm93Zss/Tonebender-MKII-Si-NPN-Verified.png) (https://postimg.cc/bdm93Zss)
ahh yes sir, 100% that is exactly what I am talking aboot. consider this confirmation.