March 25Mar 25 Bought these in Amazon: 1. Amazon.com: 3.5mm Stereo Audio Switch Audio Switcher Passive Speaker Headphone Manual Selector Splitter Box Audio Sharing : Electronics 2. Amazon.com: NC XQIN 2 Pack Aux Cord 6.6 ft/2m - 3.5mm Audio Cable Aux Cable for Car,Nylon Braided Audio Cable 3.5mm Male to Male for Headphone, Speaker, Phone, Car Stereo : Electronics For this old speaker set: Amazon.com: Klipsch ProMedia 2.1 THX Certified Computer Speaker System (Black) : Electronics and this old Sennheiser HD500 A headphone purchased way back when for 100s of U$. I have just about given up trying to use these without hum or static in both speaker or in the headphone. Are there better ones which will not have sound or background hum issues?
March 25Mar 25 Sounds like you have a ground loop between the two audio sources, which happens when the two PC chassis grounds are at slightly different potentials, causing a tiny current to flow across their common ground leads. In a very low voltage circuit like the line-level inputs to a powered speaker system, that's enough to produce a very noticeable hum. The solution is to put an isolation transformer between one of the audio sources and the switch box. There are commercially-available hum eliminators designed for electric musical instruments (e.g. the $17 Pyle-Pro PHE300 on Amazon) that would probably do the trick. It would also entail using adapter plugs or cables to convert the 3.5mm PC stereo audio plug to/from the 1/4" TRS plugs used by instruments. Bob Scott | President and CEO, AVSIM Inc ATP Gulfstream II-III-IV-V Sys1 (MSFS20+24/XPlane12+11): AMD 9800X3D, water 2x240mm, MSI MPG X670E Carbon, 64GB GSkill 6000/30, nVidia RTX4090FE Alienware AW3821DW 38" 21:9 GSync, 2x4TB Crucial T705 PCIe5 + 2x2TB Samsung 990 SSD, EVGA 1000P2 PSU, 12.9" iPad Pro Thrustmaster TCA Boeing Yoke, TCA Airbus Sidestick, Twin TCA Airbus Throttle quads, PFC Cirrus Pedals, Coolermaster HAF932 case Sys2 (P3Dv5/v4): i9-13900KS, water 2x360mm, ASUS Z790 Hero, 32GB GSkill 7800MHz CAS36, ASUS RTX4090 Samsung 55" JS8500 4K TV@60Hz, 3x 2TB WD SN850X 1x 4TB Crucial P3 M.2 NVME SSD, EVGA 1600T2 PSU Fiber link to Yamaha RX-V467 Home Theater Receiver, Polk/Klipsch 6" bookshelf speakers, Polk 12" subwoofer, 12.9" iPad Pro PFC yoke/throttle quad/pedals with custom Hall sensor retrofit, Thermaltake View 71 case, Stream Deck XL button box Sys3 (DCS/P3Dv4/ATS/ETS): AMD 7800X3D, MSI MPG X870E Carbon, Noctua NH-D15S, 64GB GSkill 6000/30, EVGA RTX3090 Alienware AW3420DW 34" 21:9 GSync, Corsair HX1000i PSU, 4TB Crucial T705 PCIe5 + 2TB Samsung 970Evo Plus, TM TCA Officer Pack, Saitek combat pedals, TM Warthog, TM RS300 FF wheel/pedals, Coolermaster HAF XB case
March 28Mar 28 Author On 3/24/2026 at 9:35 PM, Bob Scott said: Sounds like you have a ground loop between the two audio sources, which happens when the two PC chassis grounds are at slightly different potentials, causing a tiny current to flow across their common ground leads. In a very low voltage circuit like the line-level inputs to a powered speaker system, that's enough to produce a very noticeable hum. The solution is to put an isolation transformer between one of the audio sources and the switch box. There are commercially-available hum eliminators designed for electric musical instruments (e.g. the $17 Pyle-Pro PHE300 on Amazon) that would probably do the trick. It would also entail using adapter plugs or cables to convert the 3.5mm PC stereo audio plug to/from the 1/4" TRS plugs used by instruments. Thank you. Thank you! Your reply made me check and I found the perfect solution. Fixed the sucker... Amazon.com: ZIOCOM Ground Loop Noise Isolator, Noise Filter, Eliminate The Buzzing Noise for Your Car Audio System/Home Stereo with Jack 3.5mm Audio Cable (1 Pack) : Electronics
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