Grounding techniques

[flester]

This is amp.  https://imgur.com/gallery/0DvnHiX

Works fine with this ps. not much noise using pedals on battery. https://imgur.com/gallery/49d8gK3

The noise comes in when I use this.
http://imgur.com/gallery/02LCUTt

Works well with a friend's  amp and



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[flester]

Problem solved. I changed the mains adaptor supplying the pedal power supply. Noise now much at unacceptable level. Thanks again for your input. it stopped me going off om a fruitless and maybe expensive tangent! All for the price of four 9v batteries.

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[flester]

The mains adapter that worked has now died. Any tips on how to buy a new one that is not noisy?

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[electrucio]

Hi everyone,

I'm new here, pleased to join this forum! I'm picking my audio electronics hobby back up again after putting it aside for a really long time.

https://electrucio.substack.com/p/ground-loops

I would like to share a compilation of ideas I did about this topic, I hope it is useful for someone.

[aquataur]

Hi,
thanks for the great write-up.
I particularly like the section on ground planes, because people splash ground planes over all PCBs, thinking that this relieves them from a thoughtful routing.

For balanced inputs (and many other hum related subjects), there is a paper by Bill Whitlock from Jensen Transformers called Design of High-Performance Balanced Audio Interfaces, hosted by Rod Elliott. He explains in depth that the balance does not mean symmetric signals, but balanced impedances.
It would nicely fit your write-up.

You may also be interested in:

• Power and Grounding for Audio and Video Systems
  A White Paper for the Real World – International Version, Jim Brown, Audio Systems Group, Inc.
• TUTORIAL 5450 (Maxim) Successful PCB Grounding with Mixed-Signal Chips -
  Follow the Path of Least Impedance, By: Mark Fortunato
• A practical guide to high speed printed-circuit-board layout, by John Ardizzoni (Analog.com)

If anybody thinks - I only do audio stuff, that does not concern me... let me correct that: audio amplifiers love to oscillate in the MHz region. Once at least.
It is really a rabbit hole you are opening up here, but for serious design, it is inevitable to dive into.
I guess all amp designers did so.