Wiring jacks - DC/DC Converters - multiple gnd

[tuckster]

Hi everyone,

is there a best practice when using a dc/dc converter like the Traco Tec-2 series when it comes to grounding the in and output jacks?
For example one provides +15/-15V and Com. Com as circuit ground.
When I look at the Aion build notes like for the TS-50 the PWR GND and GND are connected
https://aionfx.com/app/files/docs/ts50_bass_preamp_documentation.pdf
In the schematic there is only one GND mentioned.

Now is it best to put the jacks on GND or Com or connect GND and Com and mix it all together?

With a previous build I used Com for the jacks but the Aion wiring diagram made me curious.

[antonis]

You may consider power grounds Z1 Anode, C22 & C23 negative legs and DC/DC converter pin 1..
All the other GNDs should be considered circuit grounds (common)..

Then, follow page 12 wiring diagram..
(power ground directly to DC jack ground and circuit ground to DC jack ground via Input jack ground..)

[tuckster]

Then, follow page 12 wiring diagram..
(power ground directly to DC jack ground and circuit ground to DC jack ground via Input jack ground..)

Can you elaborate why it should be this way?

[antonis]

'Cause signal ground path(s) must carry the least possible current and be free of any noise/ripple..
Power supply (DC jack) ground should be considered mother of the grounds (DC or AC)..
(mains ground claims grandma's post..)

[MikeA]

Antonis, as a thought experiment, would your answer be different if the DC ground is floating (not earthed) and the earth ground is provided via the amp, by way of the pedal's output jack shield?

[antonis]

I can't get you Mike..

All full-wave rectified DC grounds are "floating"..
(in the mean of they are terminated to bridge diodes anodes..)

Could you plz post a draft schematic of what you mean..??

[MikeA]

Imagine a bench DC power supply with the negative strapped to chassis ground.

[anotherjim]

That would be cheating Mike. Out in the field, AC ground-isolated supplies are the norm. On my bench, everything is only grounded by my test amp. If it's not audio I either let the ground float or use the ground clip of my scope probe which is AC line grounded.

[antonis]

Imagine a bench DC power supply with the negative strapped to chassis ground.

Unfortunately, my imagination's margins are very narrow..
(especially when dealing with mains safety wiring..)