non metal casework

Bibio

Member
2009-03-08 3:36 am
i'm planning on building my casework from Ash hardwood and Acrylic so there would be no place for the mains ground/earth. i'm in the UK so mains are 230vac

is this wise or would i be better to make at least the bottom out of Stainless steel?
 
Wood is fine, provided all external metalwork is grounded. Preferably, major items of internal metalwork too, such as mains transformer frames. Check that if the live mains lead became free the unit would still be safe, whatever the mains touched.

You will have to take more care over screening/shielding with no metal case to keep out interference. A large piece of grounded metal inside will help.
 
Wood is fine, provided all external metalwork is grounded. Preferably, major items of internal metalwork too, such as mains transformer frames. Check that if the live mains lead became free the unit would still be safe, whatever the mains touched.

You will have to take more care over screening/shielding with no metal case to keep out interference. A large piece of grounded metal inside will help.

Also aluminium foil normally used in kitchen will give RF interference screening.
 

Bibio

Member
2009-03-08 3:36 am
i'm using 4x 120va 2x12va toroidal transformers coupled to 8x rectifiers that have no ground lead for the unregulated powers supply in one case then an umbilical to the component case which will house the phono stage and headphone amp. the cases will be roughly 6 inches apart.
 

Mihkus

Member
2012-07-22 8:01 pm
If your device has to be shielded from external devices you need to shield your device.

Why stainless...

It would work out if sensitive devices inside are shielded.

If your device is grounded and mains is not connected to case of metal your totally fine.
 

Robert Kesh

Member
2012-10-28 3:20 pm
You can buy copper foil sticky backed sheeting to line the inside of the wood if you feel it's necessary. It's fairly cheap. I've used it to line the cavity of electric guitars, it works well for the 10s of mV signal they develop. Might not be necessary for line level.
 

Bibio

Member
2009-03-08 3:36 am
why stainless? as i get it made for free.

thanks people. i suppose when i build them and populate them and i get interference then i'll have to line them.

TBH i was more concerned about the possibility of electrocution but every live wire will be insulated with heat shrink and the only thing that will be live to touch are two bus bars and i suppose i could put a cover over those (not that anyone will be sticking their fingers in it apart from me :)
 

Dave R

Member
2006-08-09 5:30 am
I appreciate the beauty of wood myself. For my tube amp, I compromised with a wood frame with an aluminum top plate.

One trade-off was that I had to lean on a friend with metal cutting tools. :D
 

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Bibio

Member
2009-03-08 3:36 am
One trade-off was that I had to lean on a friend with metal cutting tools. :D

i have access to a full sheet guillotine, CNC turret punch press and a CNC 80ton press, tig etc.etc and the workshop specialises in making stainless steel boxes but by the time its all drawn out in Radan and change of punches in the turret i would have drilled and assembled the top and bottom in Acrylic. if push comes to shove i'll make a liner of copper sheet.

that wooden casework is lovvverly :)
 

Bibio

Member
2009-03-08 3:36 am
i was toying with the idea of Mother Of Pearl inlay splashes here and there on the front of the cases but i don't have the skill for that. but i would really love to do it or even add guitar herringbone edging as i love musical instruments that have had inlay work done.