khunaus Posted January 14, 2020 Posted January 14, 2020 Hi, I recently purchased some Kef LS50W speakers and whilst connecting to various sources noted a hum when using the RCA connects. The speakers were /are connected from an AVR's pre outs. I have noted the hum is also present when I physically touch the right input RCA but not the left input (with nothing else other than power connected.) is this a normal occurrence? I can notice the low hum noise when there are quiet scenes in a TV show but my kids can hear a higher pitched sound all the time. Cheers
Guest Posted January 14, 2020 Posted January 14, 2020 to the forum. Suggest swapping left and right channels, swapping cables. If the hum moves between left and right, then likely to be AVR (what is make, model?). Also, can you try another input to LS50W?
khunaus Posted January 21, 2020 Author Posted January 21, 2020 Thanks for the welcome, been here for a while but first post With too much travel for work I just got to test this out... It seems the hum is when the KEF's volume is at around 75% (ish) or higher and when on RCA. this is present on all sources tested (2 receivers) Yamaha RX A3080, Onykyo NR818 (original one hum was noticed on) and also on my Mac and PC. the hum can be heard even when equipment is off (but is plugged in). I had the volume this high when testing, as it was connected to the left right channels of the home theatre which also doubles as a music area. is this a normal thing given the volume level or should I keep testing / be concerned. Cheers
Guest thathifiguy Posted January 21, 2020 Posted January 21, 2020 14 minutes ago, khunaus said: Thanks for the welcome, been here for a while but first post With too much travel for work I just got to test this out... It seems the hum is when the KEF's volume is at around 75% (ish) or higher and when on RCA. this is present on all sources tested (2 receivers) Yamaha RX A3080, Onykyo NR818 (original one hum was noticed on) and also on my Mac and PC. the hum can be heard even when equipment is off (but is plugged in). I had the volume this high when testing, as it was connected to the left right channels of the home theatre which also doubles as a music area. is this a normal thing given the volume level or should I keep testing / be concerned. Cheers I experienced something similar previously and I think you'll find it is due to how high the gain is having to be set on the AVR in order to accomodate volume matching on the LS50W.
Guest Posted February 1, 2020 Posted February 1, 2020 Tarkan is correct - this does seem to be a common theme in using AVRs and a secondary amp (in this case the in-built of the LS50W) where hum becomes present. Run your sources direct to the KEFs and the hum should disappear irrespective of volume.
khunaus Posted February 6, 2020 Author Posted February 6, 2020 thanks for the replies... as you say I can run USB, bluetooth and wireless without hum ad any volume, though as I wanted to have these as left and right channels in a 5.1 system and also as music speaker via the AVR the Hum is a problem, so not sure my next steps, as isolating just these channels via other means is not something I think I can do. Cheers
blybo Posted February 7, 2020 Posted February 7, 2020 41 minutes ago, khunaus said: as I wanted to have these as left and right channels in a 5.1 system I've heard the LS50 is not forgiving of being over driven so maybe not the greatest choice for a HT setup where dynamics can be huge. Others on here have reported technicians saying they are prone to cone damage when run at high volume.
khunaus Posted February 8, 2020 Author Posted February 8, 2020 On 07/02/2020 at 10:20 AM, blybo said: I've heard the LS50 is not forgiving of being over driven so maybe not the greatest choice for a HT setup where dynamics can be huge. Others on here have reported technicians saying they are prone to cone damage when run at high volume. interesting thanks... do you have any links? i've not noticed it on any of the KEF marketing material .
blybo Posted February 8, 2020 Posted February 8, 2020 1 hour ago, khunaus said: interesting thanks... do you have any links? i've not noticed it on any of the KEF marketing material . somewhere on this site but can't remember what thread. I've seen it mentioned a few times so I doubt think it's a massive secret or anything. Every product has pro's and con's. I'd love a set of LS50W or LSX's for my office, but not for my HT room.
khunaus Posted February 8, 2020 Author Posted February 8, 2020 ok thanks, coincidently these are currently being used in my office, but that is not what I purchased them for and I've still got the "hum" issue. I'll see if I can go to KEF direct to see what they say on the topic. Cheers
gwurb Posted February 9, 2020 Posted February 9, 2020 Have you tried using your phone or something else as an audio source with 3.5mm stereo to RCA cable? Are your cables double shielded?
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