spritzer Posted November 14, 2020 Report Share Posted November 14, 2020 If you have some transformers floating around, it would be simple enough to make a cheap linear supply to try out. Add some beefy caps in a CRC or CLC setup... 1 Quote Link to comment Share on other sites More sharing options...
themystical Posted December 28, 2020 Report Share Posted December 28, 2020 https://flic.kr/p/2kmuC9i https://flic.kr/p/2kmqddS I have used the holiday period to build this amp but I am unfortunately having a mains hum similar to some other builds. Not having used SMPS before, am I missing a trick? Is there some sort of filter that I need to insert to make it hum free? 1 Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 28, 2020 Author Report Share Posted December 28, 2020 wire the headphone grounds directly to the amp boards, not the power supply Quote Link to comment Share on other sites More sharing options...
themystical Posted December 28, 2020 Report Share Posted December 28, 2020 5 minutes ago, kevin gilmore said: wire the headphone grounds directly to the amp boards, not the power supply Thanks Kevin. That is what I have done. I have balanced inputs so the signal/chassis ground is isolated from the smps and amp board grounds. In other words the smps power ground and output signal negative is floating and not tied down. I probably need to do a bit more experiments to try and identify the issue I.e. whether it is conducted noise from the SMPS, EMI pick up, earth loop etc. I was just wondering whether there was some standard EMI suppression filter required with SMPS? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 28, 2020 Author Report Share Posted December 28, 2020 this is not a balanced input amplifier Quote Link to comment Share on other sites More sharing options...
jp11801 Posted February 15, 2021 Report Share Posted February 15, 2021 has anyone fully built his amp up and would be willing to put together a second one for someone that is totally inept with a soldering iron and schematics, asking for a friend 🙂 2 Quote Link to comment Share on other sites More sharing options...
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