This might seem a dumb question... I'm building a Tiny Giant amp into a simple cab (an upside down Ikea "Rast", see pic!), with a couple of Jensen Mod 8" speakers... The space at the top of the Rast is exactly 2RU 19" rack panel size. I can mount knobs etc onto the rack panel with the Tiny Giant PCB behind it... My question is, does the amp PCB require an aluminium enclosure to shield against RF/hum etc? In which case, can I still have wires coming out of the enclosure to connect with the pots & switch etc on the front rack panel?
My confusion comes from seeing some DIY amps fully enclosed, others half-enclosed, others not at all, etc etc...?
I hope I'm making sense here lol.
(Rast unit below - imagine it upside down!)
(http://www.ikea.com/au/en/images/products/rast-bedside-table__22234_PE094189_S4.JPG)
Short answer is YES,, you need a chassis otherwise you go mad trying to run coax cable all over the place. build it all in a rack case and be done with it.
Phil.
Thanks I'll look fr a 19" aluminium rack case then
You could flip that thing upside-down and build a metal chassis on the "bottom", screwed to the sides. Then just use two wooden planks for the front and back and voilá!
Simply drill a hole in the midde of the bottom (now your top) piece to run the wires for the speakers. That way you can have a better closed area for the speakers.
Like this (quickly done in paint, sorry!) :
(https://40.media.tumblr.com/f619e742a2d26f540ce7f5cc688e82ee/tumblr_nrpvoltxeO1r4gqjso1_500.png)
Attached it just in case tumblr decides to delete the image.
Agree and add: does the OP have access to a friendly sheet metal shop?
Not necessarily a monster factory punching out car doors or fridge cabinets, but maybe a small/neighbourhood type , all you need is access to a shear and a simple folder, in fact some car body repair shops have them to make simple parts.
If so, they will be able to cut and fold a simple "U" shaped chassis for peanuts.
This is one I made in 1972, housing a then impressive 200W RMS amplifier, out of 2 mm aluminum sheet .
(http://farm2.staticflickr.com/1161/729090782_3241825d35_o.jpg)
By the way, it's still working every weekend until now, 44 years later 8|
Now I cut and punch my own, but way back them I visited some "tin shop" , those who make custom rain gutters, air conditioning conduits, stove chimneys, etc. and asked the guys for some help.
They didn't even want to charge me, but I always carried with me, "just by chance" , a couple "longnecks" (wine somewhat better than their usual one) and "forgot" them over the counter.
I was *always* welcome ;)
And really, cutting a rectangular piece of aluminum and folding it twice takes a couple minutes, but of course the machines must be free and not in the middle of a production run.
I left the aluminum and the bottles and came back next day :)
Last detail: being surrounded on 3 sides by grounded metal is almost always enough, but if needed, you can glue to the wooden side closing your cabinet a sheet of kitchen type aluminum foil and ground it, a very common trick, used even by Fender and Marshall, go figure.
Quote from: blackcorvo on July 19, 2015, 12:05:13 AMYou could flip that thing upside-down and build a metal chassis on the "bottom", screwed to the sides. Then just use two wooden planks for the front and back and voilá!
Simply drill a hole in the midde of the bottom (now your top) piece to run the wires for the speakers. That way you can have a better closed area for the speakers.
Thanks blackcorvo! Yes I plan to use the cab upside-down (as I mentioned in my first post heh) ;) This unit is actually a perfect size for a couple of 8"s, solid pine too, and next-to-nothing costwise.
Quote from: J M Fahey on July 19, 2015, 05:22:04 AMbeing surrounded on 3 sides by grounded metal is almost always enough, but if needed, you can glue to the wooden side closing your cabinet a sheet of kitchen type aluminum foil and ground it, a very common trick, used even by Fender and Marshall, go figure.
Ah thanks Mr Fahey! That's what I was wondering! Well, as it happens, I did find an enclosed 19" aluminium rack case online for a good price that will fit into the "top" section (actually "bottom") very nicely. Nice to know about the aluminium foil trick, thanks.
This is a labour of love that's been dragging along too long now, I'm gonna step it up a notch & post results when I can.