We all have been in trouble once in a while.
I can’t help you with everything (“What’s the meaning of life?“), but if it comes to switching and routing signals, LEHLE is a good address to start.
E.g. I get an inquiry from a customer with the subject “HELP!!!“ and in the message the customer tries to explain the signal path he’s/she’s struggling with or that there’s a hum or high pitched noise he/she can’t get rid of.

Often there are confusions because a customer writes: “connected my amp to the pedal and then into the guitar“. Really? I didn’t know the amp is sending a signal? Or “As suggested I disconnected everything and only the effects board is running“. I’m very sorry, but there are way too many connections for me to find out if pedal XYZ is the reason for a problem.
I’d like to give you some tips in how to start if you’re struggling with a problem:

• Disconnect everything. Really. Everything. No-one can find a humming needle in a haystack. There are way too many connections which could cause interferences. Start with your instrument, your cable and the amp and add the pedals one by one.
• If you suppose that your LEHLE pedal is humming, just use the LEHLE pedal. If you suppose your delay is buzzing, just use the delay.
• Power supplies. Totally underrated. Please don’t use your cell phone charger to power your $ 300 boutique pedal. Spend some money in a high-quality power supply, which can safe you from a serious hum at the next gig.
• Follow the white rabbit! Your signal is going out of the guitar into a pedal and out of the pedal into an amp. Not vice versa. Think of trains and rails. No-one wants to go by train from the destination backwards. If you’re troubleshooting, the direction of the signal is everything. If you aren’t sure which direction your signal goes, you don’t need to start searching at all.
• Physics and Electronics are not magic! If wished we can help you understanding the basics, which can be helpful for your setup. Although sometimes it seems like it’s magic.
• The earth is flat! No, it isn’t, or? Choose wisely between the information you get, but at the end of the day simply trust your ears and of course tastes matter too.
• Cables. I know that your beloved cable has worked for years now. But please check, replace or test it with another cable. Sometimes we miss the obvious things.

• Sketch the signal flow. If you have a huge pedalboard or rig, it’s possible that we lose track. Make yourself a coffee or tea, take paper and pencil and draw your pedals, cables, power supplies and their connections, amps and instruments. Use little arrows for the start, signal flow and destination and maybe use colored pencils for the different kinds of signals: audio, midi, power, speaker signal, switching signal, etc. It helps a lot and you will laugh about, how you could have connected the amp’s send to the out of a pedal.
• By the way: the answer is “42“.