Hi, I'm interested in building a 1 input 2 output (3.5mm) A/B switch. At first I was looking to purchase one, but all the small units like I need have reports of noise being added to the signal because of poor, or no shielding. I've found several instructables on building something I can use, but none mention shielding. Any suggestions or ideas on how to achieve this? I created the image as I imagine it would work?
Headphones are low impedance, so shielding should not be necessary,
but you can use a steel or aluminum enclosure. Connect it to the headphones
common ground wire.
but you can use a steel or aluminum enclosure. Connect it to the headphones
common ground wire.
You don't need a physical switch, nor even a box. If You use a switched jack when You insert the headphones the speakers are disconnected.
In the drawing, the 3.5mm is to powered speakers. All the ready made units I investigated had complaints of noise being added from the channel that was not used.
The purpose of a switched 1/8" phone jack is to turn the speaker off when you plug in the headphone. Or to turn off the internal cheap speaker when you plug in a better expensive speaker. So in post 1 the jack to the klipsch speaker doesn't need to be switched. The switch on the headphone jack would turn off the klipsch speaker.
Again, a steel box is adequate for shielding. Say, a steel altoids box?
Shielding is usually not used for speaker level wiring because the speaker shorts out the RF and doesn't respond to it. What can happen is the speaker picks up RF and injects it in the feedback line of the power amp, causing the power amp to turn that into audible signals. Real power amps have a coil near the speaker jack, to block the RF coming in from the feedback line with inductance. Laptops probably don't have such a coil. Inductor is usually the size of a AA battery, 11 to 14 turns. If your laptop starts picking up RF, put a 1' cable between it and a real power amp with such a device. You can't modify a laptop, there is no room.
I can't believe you are trying to run speakers with a laptop earphone jack. I have a pair of unpowered speakers made for that, 32 ohm, and they are so soft when trucks drive by on the road 80' away I can't hear the program. Or motorcycles or scooters with loud mufflers.
If your klipsch "speakers" are active, have internal amplifier, and pick up RF, then change to a passive speaker with the amp in the box with the switched headphone jack. A used Peavey amp will have internal RF blocking. I don't know about other brands, some are good, some are ****. Any active speaker that picks up RF from the audio cable is ****.
I just picked up a 150 W mono Peavey mixer amp MMA-8150 for $85 including shipping from Florida. My other Peavey mono mixer amp MMA-875 was $70 including shipping. Have all the RF blockers, internal speaker DC protection with a transformer. So I've got a power strip for two plugs, big problem. Class AB, leaded components, totally repairable with a $60 iron, no fan required. One will ride to gigs in my bicycle bag, the speaker , mikes & musical instrument in the other bicycle bag.
Again, a steel box is adequate for shielding. Say, a steel altoids box?
Shielding is usually not used for speaker level wiring because the speaker shorts out the RF and doesn't respond to it. What can happen is the speaker picks up RF and injects it in the feedback line of the power amp, causing the power amp to turn that into audible signals. Real power amps have a coil near the speaker jack, to block the RF coming in from the feedback line with inductance. Laptops probably don't have such a coil. Inductor is usually the size of a AA battery, 11 to 14 turns. If your laptop starts picking up RF, put a 1' cable between it and a real power amp with such a device. You can't modify a laptop, there is no room.
I can't believe you are trying to run speakers with a laptop earphone jack. I have a pair of unpowered speakers made for that, 32 ohm, and they are so soft when trucks drive by on the road 80' away I can't hear the program. Or motorcycles or scooters with loud mufflers.
If your klipsch "speakers" are active, have internal amplifier, and pick up RF, then change to a passive speaker with the amp in the box with the switched headphone jack. A used Peavey amp will have internal RF blocking. I don't know about other brands, some are good, some are ****. Any active speaker that picks up RF from the audio cable is ****.
I just picked up a 150 W mono Peavey mixer amp MMA-8150 for $85 including shipping from Florida. My other Peavey mono mixer amp MMA-875 was $70 including shipping. Have all the RF blockers, internal speaker DC protection with a transformer. So I've got a power strip for two plugs, big problem. Class AB, leaded components, totally repairable with a $60 iron, no fan required. One will ride to gigs in my bicycle bag, the speaker , mikes & musical instrument in the other bicycle bag.
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