I've finished the electronics (Boozhound kit) and power supply (another Boozehound kit) for my phono pre amp. I should note that my skills in electronics are limited to soldering and following instructions. My true enjoyment comes from designing the enclosures or otherwise customizing the cosmetics, hence my questions.
I'm attempting a cool minimalist enclosure that's basically a block of black walnut with nothing but a thin strip of frosted Plexiglas embedded in it to indicate that it's powered on. i'm having a local CNC shop hollow it out to form separate chambers for the power supply and pre-amp and the holes needed to accommodate the connections.
I was hoping to incorporate a proximity switch that would sit just under the surface of the wood to be able to turn the unit on and off by touching the top.
My research shows inductive, capacitive and magnetic switches.
Of the three, the first two might work for "flesh" (ie a finger or hand) being placed on the box and the third opens up the interesting possibility of placing a metal ball-bearing or cube or even another piece of wood with metal inside it in a slight depression to turn the power on. Something which appeals to me in a kind of magical key fantasy way.
Does anyone know if these are viable options? Do they introduce noise? Are they too big for the planned 12 inch wide by 3 inch tall by 6 inch deep enclosure? i'm not averse to making a separate power supply and connecting the two with an umbilical if need be, but I would rather keep it simple.
I'm attempting a cool minimalist enclosure that's basically a block of black walnut with nothing but a thin strip of frosted Plexiglas embedded in it to indicate that it's powered on. i'm having a local CNC shop hollow it out to form separate chambers for the power supply and pre-amp and the holes needed to accommodate the connections.
I was hoping to incorporate a proximity switch that would sit just under the surface of the wood to be able to turn the unit on and off by touching the top.
My research shows inductive, capacitive and magnetic switches.
Of the three, the first two might work for "flesh" (ie a finger or hand) being placed on the box and the third opens up the interesting possibility of placing a metal ball-bearing or cube or even another piece of wood with metal inside it in a slight depression to turn the power on. Something which appeals to me in a kind of magical key fantasy way.
Does anyone know if these are viable options? Do they introduce noise? Are they too big for the planned 12 inch wide by 3 inch tall by 6 inch deep enclosure? i'm not averse to making a separate power supply and connecting the two with an umbilical if need be, but I would rather keep it simple.
Will your "cool minimalist enclosure" provide adequate cooling for the electronics? Wood is not a good conductor of heat so I trust you have incorporated some ventilation holes in your design?
Does someone make mains-rated proximity switches?
Does someone make mains-rated proximity switches?
Well yeah... it's a "cool" enclosure after all. 🙂
Ventilation is not a problem as the bottom will be open and the rear will have vents cut into it. Is there ENOUGH cooling? Well, that's what experimentation is all about.
Not that a pre-amp is going to get all that hot. Here is the link to the electronics involved.
https://boozhoundlabs.com/collections/all/products/deluxe-phono-peramplifier
https://boozhoundlabs.com/collections/all/products/power-supply-kit
My idea is to make it so that a finger or object placed on top will turn it on but I see that these switches emit EM fields and wonder if there will be noise. Also, are they small? Can they sense through a thin piece of wood?
Ventilation is not a problem as the bottom will be open and the rear will have vents cut into it. Is there ENOUGH cooling? Well, that's what experimentation is all about.
Not that a pre-amp is going to get all that hot. Here is the link to the electronics involved.
https://boozhoundlabs.com/collections/all/products/deluxe-phono-peramplifier
https://boozhoundlabs.com/collections/all/products/power-supply-kit
My idea is to make it so that a finger or object placed on top will turn it on but I see that these switches emit EM fields and wonder if there will be noise. Also, are they small? Can they sense through a thin piece of wood?
Are there mains-rated reed switches? If so, fine. If not, the reed switch will have to activate a relay.
What about placing the reed switch in line with the output of the power supply? The output is 18VDC. The main switch can be a traditional toggle that I hide on the back, and the reed can be in the phono section.
Is that a viable option?
Viable as what? It doesn't turn the supply off, just stops the preamp from working. As leaving the preamp running will do no harm I'm not sure what it will achieve apart from a huge click when you turn it on again.
First consider the power that "magical key" feature needs.
You'll need a second, standby power supply if You want to switch the preamp's mains with a secondary circuit. This needs room in Your enclosure.
After You have power, You can use a small signal reed relay (the glass house with metallic contacts) and a magnet to switch a transistor that drives the mains relays. It does not induce noise or such.
Using a capacitive sensor You need a sensing plate, a surface to touch. Practically some metal. Since some sensor IC is capable to output pulses or even act like a toggle switch, the transistor driver part can be the same.
Some things to consider: how can you set the sensitivity, and the IC package since these are not typically DIP socketable ICs.
If You like the magnetic idea, there are magnetic sensors too, like a compass, that is more sensitive than a reed relay, this can be more space (or wood) between.
You have plenty of options.
You'll need a second, standby power supply if You want to switch the preamp's mains with a secondary circuit. This needs room in Your enclosure.
After You have power, You can use a small signal reed relay (the glass house with metallic contacts) and a magnet to switch a transistor that drives the mains relays. It does not induce noise or such.
Using a capacitive sensor You need a sensing plate, a surface to touch. Practically some metal. Since some sensor IC is capable to output pulses or even act like a toggle switch, the transistor driver part can be the same.
Some things to consider: how can you set the sensitivity, and the IC package since these are not typically DIP socketable ICs.
If You like the magnetic idea, there are magnetic sensors too, like a compass, that is more sensitive than a reed relay, this can be more space (or wood) between.
You have plenty of options.
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