i know, i know, expensible mains cables etc are all a big con

but

i just bought a new setup – wharfedale lintons and leak stereo 130 amp. i was enjoying the sound but i started noticing a strange hum, fading in and out, easily audible at least 5m away.

turns out it was coming from the transformer of the amp itself. that is, audible even with no speakers attached.

i tried reproducing in the morning – nothing (unless pressing my ear up to it). but the next evening it came back.

i have a battery backed ups/apc thing. so i added that. yes i am a nerd.

powering the amp via ups via mains (ie just surge protection) the issue is still present.

switching off at mains and unplugging has same effect (and i am in the uk, there is an earth pin) – the hum stops phasing in and out and changes to an entirely consistent, quite quiet, and more buzzy hum (and the ups beeps obviously, which is annoying).

SO

should i buy some snake oil product, assume my amp is faulty and replace it like-for-like, get a different amp, stick it in a cupboard, learn to love it, or something else?

plan a is to at least hold my ear up to replacement one in the shop, and if it is audibly different up close then go from there, but i am thinking this might be inherent to the product…

  • thegarbz@alien.topBEnglish
    1·
    10 months ago

    Potential problems and solutions:

    • Transformer winding has come loose due to poor manufacturing QC, does happen, need to get it fixed.
    • Downstream component failing (failing capacitor can cause uneven current draw, as can failing diodes). Sometimes this problem is thermal related and changes with how long the amp has been on. Sometimes it’s load related. need to get it fixed.
    • DC on the mains. Some designs are crap and don’t tolerate AC on the mains. If this is the issue the noise will vary with time of day and activity in the house (i.e. does it only hum while the wife is using her hair dryer on low?). Ideally throw out your garbage equipment and buy something designed by someone who understands how mains electricity works, or buy a DC blocker to work around their incompetence.
  • spartree@alien.topBEnglish
    1·
    10 months ago

    I’m currently experiencing a similar problem with a tube preamp and a tube DAC. Both were originally wired for 220V and were dead silent when running on said voltage in Europe. They also worked fine via at step-up transformer after I moved myself and them to Canada. They have since been converted to 120V operation via the manufacturer’s instructions with work performed by an authorized shop, and now they both buzz like crazy from their transformers. And it does seem to cycle between a loud buzz to a relatively quiet one over several minutes, perhaps similar to what you are experiencing.

    I’ve tried a DC blocker (Ava Humdinger) and an isolation transformer (Decware ZLC), but neither one helped. I will try a UPS next just to completely rule out any issues with the mains supply/household wiring. Otherwise it’s back to the shop with them…

    Hope you get yours sorted. Please be sure to report back if you do.

  • yolobastard1337@alien.topOPBEnglish
    1·
    10 months ago

    update: i got an audiolab dc block, and have finally tested it.

    it… helps. a lot. but it does not solve it completely – certainly up close. i’ll give it some use and see how i feel.