Hiraga wiring check - Another grounding question sorry

[doolybird]

Hi All,

Had a decent read of many posts and I think this is the correct way to wire my Hiraga build. Just a hobbyist so looking for confirmation this looks ok. My main query is in regards to the IEC safety and the circuit/star ground. Is there continuity between the two ? Hopefully picture comes through.

Thanks in advance

Richard

 

[JonSnell Electronic]

To comply with safety, is is a good idea to use a pair of diodes back to back as shown.
1n540* types are fine and the voltage rating doesn't matter as we are only talking a few milivolts, so 1n5401 - 8
Otherwise if the ground wires are 16 SWG/AWG all should be fine.

 

[russc]

Shouldn't the speaker negative go straight to the speaker negative terminal on the board which will be close to the output stage?
As drawn, the heavy fluctuating speaker currents are routed in a roundabout fashion.

 

[doolybird]

Thanks for the reply. The maker of the Amp board suggested suggested wiring the speaker negative to the central ground. Not sure ?

 

[hpro]

Shouldn't the speaker negative go straight to the speaker negative terminal on the board which will be close to the output stage?
As drawn, the heavy fluctuating speaker currents are routed in a roundabout fashion.

Exactly right,
Connect the Negative Speaker terminal to the board. would be the right choice in my point of view. As short as possible..

The way it is shown in your picture you could get easy a Ground Loop between Input terminals the speakers and the Star GND itself..

Easy to detect. Switch on the amp, do not connect Input source yet at amp side. Speaker connected. Now Plug in one CHANNELS RCA and listen for HUM or noise at the speakers. If there is none then Plug in the second Channel, if you get low hum or hiss noise then the AMP has a ground loop..

With low hum I mean you could barely hear it but it is there if you place your head almost in the Speaker itself. Same for hiss on the tweeters.. And or "pink noise" on Midrange.. if it disappears when pulling the one or other RCA, then this is a sign of GND LOOP.
Enjoy Sunday

 

[Zung]

This looks like the grounding problems I encountered while working on the JC2-HPA.

• Root cause: 2x2 externally sourced PCB which may or may not play nice together.
• Fix: before committing the wiring to a harness, play around a little: start with the basic connection, listen/measure, then change around to the suggested speaker(-) to the board, etc.

I used alligator clips to experiment, but that requires extra care. I know 🙂. But now it's quiet as a grave.

 

[doolybird]

Exactly right,
Connect the Negative Speaker terminal to the board. would be the right choice in my point of view. As short as possible..

The way it is shown in your picture you could get easy a Ground Loop between Input terminals the speakers and the Star GND itself..

Easy to detect. Switch on the amp, do not connect Input source yet at amp side. Speaker connected. Now Plug in one CHANNELS RCA and listen for HUM or noise at the speakers. If there is none then Plug in the second Channel, if you get low hum or hiss noise then the AMP has a ground loop..

With low hum I mean you could barely hear it but it is there if you place your head almost in the Speaker itself. Same for hiss on the tweeters.. And or "pink noise" on Midrange.. if it disappears when pulling the one or other RCA, then this is a sign of GND LOOP.
Enjoy Sunday

OK, thankyou both. I will connect the -ve speaker terminal to the board. The connection is just the same gound GND I have already shown from the board to the Star Ground so I wasnt sure therw would be any difference.

Cheers