I just wanted to kick around some ideas for construction of tube amp projects. I have nearly always used metal chassis/boxes, but I am thinking of other materials, like wood, but then, how would I shield the circuitry?
One idea I have seen used, is to line the wooden case with aluminium foil, all glued on. Works, but is messy and can be damaged if scraped. Metallised cardboard would be nice, but I don't know where to get any.
I once used aluminium seet metal to construct and inner metal half-shell, inside a nice looking plastic instrument case. That works but is a lot of effort.
What about conductive paint? I seem to recall it's fairly expensive. Any cheap alternatives?
How about blank one-sided copper-clad circuit board? You could easily punch holes through it for tube sockets, and you could solder tag strips etc, directly to it on the copper side, then do point to point wiring from the tube socket to the tagstrips. The circuit board would make a good ground plane / shield.
One idea I have seen used, is to line the wooden case with aluminium foil, all glued on. Works, but is messy and can be damaged if scraped. Metallised cardboard would be nice, but I don't know where to get any.
I once used aluminium seet metal to construct and inner metal half-shell, inside a nice looking plastic instrument case. That works but is a lot of effort.
What about conductive paint? I seem to recall it's fairly expensive. Any cheap alternatives?
How about blank one-sided copper-clad circuit board? You could easily punch holes through it for tube sockets, and you could solder tag strips etc, directly to it on the copper side, then do point to point wiring from the tube socket to the tagstrips. The circuit board would make a good ground plane / shield.
McMaster Carr sells copper tape, various widths and lengths. Sticks pretty well to wood in my experience.
Does it work? Not sure, but in theory there is more shielding.
Does it work? Not sure, but in theory there is more shielding.
hotbottle said:
This is exactly the idea I have been kicking around myself, and if you used double-sided boards you could use the sides on the inside of the amp for the ground plain and the sides on the outside would be shielding.
-Justin
If you want to get really fancy, you could get some mu-metal to shield the inside from magnetic fields. It would be significantly more expensive (probably around $30 vs. $5-$10 for copper tape), but you do get the added benefit of magnetic shielding.
Well, the aluminium chassis I have used don't do much magnetic shielding,and they work OK, so it probably isn't necessary.
I have been looking around, and although copper tape isn't so easy to get, I have found lot's of aluminium tape. It's used for insulation, lagging, ductwork, sheet metal repair etc. and comes in rolls with good width. I think it may be a good choice.
I have been looking around, and although copper tape isn't so easy to get, I have found lot's of aluminium tape. It's used for insulation, lagging, ductwork, sheet metal repair etc. and comes in rolls with good width. I think it may be a good choice.
How about aluminium kitchen foil? It's readily available in a variety of widths. Either use aluminium solder to make your earth connection, or a solder tag.
Copper screens available at home centers work also. If all edges overlap it forms a Faraday cage. Ain't no stuff gettin' through that!
BTW American Science and Surplus sells rolls of aluminum tape at good prices and I've found copper tape on eBay in various widths.
BTW American Science and Surplus sells rolls of aluminum tape at good prices and I've found copper tape on eBay in various widths.
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