Cornet 2 shielding/grounding

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cyto

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Cornet 2 shielding/grounding
« on: 2 Jul 2013, 05:18 pm »
I received the parts for my Cornet 2 build, I am using this case (it met the WAF):

http://datasheets.globalspec.com/ds/968/DigiKey/36256CD9-C947-4E87-818D-A03F70C45606

I made a bottom plate from 16ga steel and am making a back plate to mount the ac power inlet, rca jacks (I am using the gold rca jacks from AES) and ground lug. I was planning to run a wire from the top and bottom plates to the ground lug on the back.

Should I shield the front and sides too?

I did a search and seen that some did and some did not.

thanks,   :D

David

poty

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Re: Cornet 2 shielding/grounding
« Reply #1 on: 3 Jul 2013, 06:13 am »
Should I shield the front and sides too?
What front and sides? As far as I can see - there is only a walnut frame, not metal.

hagtech

Re: Cornet 2 shielding/grounding
« Reply #2 on: 3 Jul 2013, 07:07 am »
You can try what you think will work first.  If the environment is too noisy, you can always glue in some aluminum foil later on.  It is a bit of work to shield a wooden chassis.

jh

jtwrace

Re: Cornet 2 shielding/grounding
« Reply #3 on: 3 Jul 2013, 11:12 am »

Speedskater

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  • Kevin
Re: Cornet 2 shielding/grounding
« Reply #4 on: 3 Jul 2013, 02:03 pm »
ERS Cloth?

Look's like it's optimized for the rather high radio range (MHz-GHz).
Also look's like it's difficult to work with.

hagtech

Re: Cornet 2 shielding/grounding
« Reply #5 on: 4 Jul 2013, 09:04 am »
Yeah, ERS is for RF.  And be careful with the cut edges, as I think they may be able to short things out.  Simple metal will suffice for low frequency electric fields.  Aluminum foil, copper tape, etc...

jh

cyto

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Re: Cornet 2 shielding/grounding
« Reply #6 on: 4 Jul 2013, 05:29 pm »
Thanks for the replies, I am using some thin aluminum sheeting left over from something else.

Everything is going well so far, the case is almost done and the board is 1/2 done.   :green:

lssalmin

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Re: Cornet 2 shielding/grounding
« Reply #7 on: 8 Jul 2013, 02:31 pm »
A bit OT, but I'm building the bugle with the power supply in to a case (aluminium Hammond enclosure). How should i make the grounding(s)? I have panel mounted RCA-jacks, should they be insulated?

I also have this:



I'm planning on  using both the fuse and switch, so what are the proper connections?

Thanks
Lauri

poty

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Re: Cornet 2 shielding/grounding
« Reply #8 on: 9 Jul 2013, 08:29 am »
There is already mains "line" input connected to the fuse. From another end of the fuse and from the "neutral" input - to the switch in the same module. From the switch - to the primary coil of the power supply. The "ground" input - to the ground binding post bolted to the case (no insulation!!!). Outputs of the power supply should be connected to batteries holes, the switch on the Bugle PCB should be wired in the "on" position permanently.
The RCAs should be insulated (do not touch the chassis in any way) and connected by twisted pair or shielded cable to the inputs of the Bugle PCB. Keep the wires short! The same consideration should be good for outputs.
The "ground" of the Bugle PCB should be connected to the abovementioned binding post. That is all about connections.

Speedskater

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  • Kevin
Re: Cornet 2 shielding/grounding
« Reply #9 on: 9 Jul 2013, 01:00 pm »
The AC power Safety Ground (EGC/PE) of the above IEC module should have a short Green wire bonded to the chassis. Bonded means, make a very secure connection.  Note that the audio circuit connects to the chassis near the Input/Output jacks.

lssalmin

  • Newbie
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Re: Cornet 2 shielding/grounding
« Reply #10 on: 14 Jul 2013, 11:43 am »
Okay great thanks!  One more question though: how do I connect this one correct  http://fi.farnell.com/multicomp/mcfm50-15/transformer-mini-5va-2-x-15v/dp/9531530?Ntt=9531530

(230Vac)

poty

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Re: Cornet 2 shielding/grounding
« Reply #11 on: 14 Jul 2013, 12:36 pm »
OK, just forgot you mean Bugle. :)
I can't find exact layout of wires' colors, but in reality, according to the datasheet:
- there should be 3 wires grouped together. The 2 with highest resistance are for primary for 230V
- 2 other groups (2 wires in each) should have near the same resistance (low). Find the wires by using the ohmmeter and then try to connect one of the wire from the first 15V group to on of the wire from the second 15V group. Connect the primary to an AC source and measure voltage across the free (not connected) leds. If the reading is around zero - then you connected the secondaries in wrong phase. Exchange the wires in one of the group and check again. There should be around 30V across the free leds.Then the primary should go to outer holes from the input side of the power supply (or connect them directly to IEC inlet), the secondaries should go in the order they connected during testing to the holes from the low-voltage side of the power supply PCB.