dantan Posted October 27, 2010 Posted October 27, 2010 Hi guys, Firstly, apologies if this has been discussed before. The other night, I noticed some humming out of my Marantz PM-KI Pearl 2-channel Integrated Amplifier, while I was removing a Blu-ray Disc out of my Blu-ray Disc Player (which is placed in the shelf rack just below). It is fairly quiet but does get louder at times (usually when I've played material quite loudly and it's been pumping out a fair bit of power). I must stress that I cannot hear the humming unless I am within about 15 centimetres from the PM-KI Pearl unit itself. Most of the time, it's only a soft continuous hum that I can hear when 15cm or nearer to it. I was just wondering if humming is natural for amplifiers. Occasionally, the hum completely disappears but most of the time, it's a soft continuous hum. Dan.
dantan Posted October 27, 2010 Author Posted October 27, 2010 Transformer hum? or? Yes, mate. Certainly appears to be a transformer hum.
betty boop Posted October 27, 2010 Posted October 27, 2010 Transformer hum? or? Often the case. Dan more prevalent if frame type transformers are used rather than torroidals. Even with torroidals as get bigger very hard to get them round which can cause hum. Often it's the mounting of the transformer that allows it to vibrate. Might just need tightening up or better mounting method. Some brands encapsulate their power supplies for this reason. And better mounting methods for this reason.
myrantz Posted October 27, 2010 Posted October 27, 2010 (edited) Yes, mate. Certainly appears to be a transformer hum. Just a random google for a link on possible solutions: linky.. Not sure how true that is TBH (so you should google and see if there are other solutions).. For me I just move the equipment around a bit (stabilise/level it) and the hum just went away ... So far it works for me every time.. Transformers do make abit of audible noises though, so a tiny wee bit of noise is probably unavoidable (I think if you put your ears right up to a transformer u can hear and feel it buzz).. Just try ur best not to accentuate it, e.g. don't put transformers/gear with transformers in tight spaces. Since you're connecting to a BD player and then to a TV I assume your gear is grounded.. To test simply run your hand over the front of your KI amp (you shouldn't feel anything static like on ur fingers).. If you do feel a bit of static however, you prob need to earth your audio gear, and there's a slight possibility it may get rid of the hum.. Just some random thoughts, may or may not work. Esp the last part.. Also note i'm talking about mechanic hum and not electrical... Often the case. Dan more prevalent if frame type transformers are used rather than torroidals.Even with torroidals as get bigger very hard to get them round which can cause hum. Often it's the mounting of the transformer that allows it to vibrate. Might just need tightening up or better mounting method. Some brands encapsulate their power supplies for this reason. And better mounting methods for this reason. +1. Edited October 27, 2010 by treblid
dantan Posted October 27, 2010 Author Posted October 27, 2010 Thanks Treblid and Al. Thanks, too, for the suggestions, Treblid. Dan.
Tweet Posted October 28, 2010 Posted October 28, 2010 (edited) The laminations that make up the transformer core may be optimized for the 60 Hertz Mains frequency in the country of manufacture. Using it here in Australia with a 50 Hertz Mains frequency might mean that the magnetizing current flowing in the primary winding would be marginally higher than what was proposed ? This is nothing to worry about but what is known as Magnetostriction in magnetizable materials is what causes the noise. (You could clamp a ' E I ' transformer core in a vice and it would still hum on regardless.) Transformer cores are generally dipped in resin to minimize the vibration created by the alternating magnetic fields fluxing in the silicon steel laminations. As mentioned, Toroidal transformers are much quieter than the ' E I ' cores of traditional transformers. A beautiful amplifier with odd looks by the way. C.M Edited October 28, 2010 by Tweet
dantan Posted October 29, 2010 Author Posted October 29, 2010 Thanks Chicken Man. I heeded Treblid's suggestion and I did move the amplifier slightly and I also unplugged and replugged the main cable and it's improved dramatically. Thanks heaps, guys. Dan.
myrantz Posted October 29, 2010 Posted October 29, 2010 (edited) Thanks Chicken Man.I heeded Treblid's suggestion and I did move the amplifier slightly and I also unplugged and replugged the main cable and it's improved dramatically. Ideally it shouldn't hum at all (at least inaudible during daytime)... Really the only sounds you should hear is just the sound of the CD spinning when up close... Edit: Not sure if this will help.. But try a different power point? Plug the IA directly into the wall socket, or even try another cable? Edited October 29, 2010 by treblid
dantan Posted October 29, 2010 Author Posted October 29, 2010 Ideally it shouldn't hum at all (at least inaudible during daytime)... Really the only sounds you should hear is just the sound of the CD spinning when up close...Edit: Not sure if this will help.. But try a different power point? Plug the IA directly into the wall socket, or even try another cable? Thanks mate. I shall try these out on the weekend. My Marantz PM-KI Pearl when switched on but not playing any Disc, is absolutely dead-silent.
myrantz Posted October 29, 2010 Posted October 29, 2010 Thanks mate. I shall try these out on the weekend.My Marantz PM-KI Pearl when switched on but not playing any Disc, is absolutely dead-silent. Yup.. It should be dead silent... Do try out anything u can (checking that the unit is stable, etc).. And if you still hear a hum, have a talk to simply hifi?
dantan Posted October 29, 2010 Author Posted October 29, 2010 Thanks mate. The first thing I tried was to ensure that it was stable, and it certainly was (and is still). I shall have a play-around with it this weekend, and see how I go. Dan.
dantan Posted November 6, 2010 Author Posted November 6, 2010 (edited) I took my Marantz PM-KI Pearl integrated amplifier to Simply Hi Fi today, and just as I guessed, not a whisper at all from it. I could not get it to hum whatsoever. I took it home and Pierre kindly lent to me a Cow King (no, really, it's called "Cow King") digital voltage readout. I plugged everything back in and yes, the hum was still there - very softly but still there. I plugged in the Cow King and it was showing about 241-244V. I went out earlier and came home, and put my ear close to my amplifier and it was humming louder than during the day. I plugged in the Cow King, and it was reading 250! I plugged it into another power outlet at another location in my home, and it also read 250! Dan. Edited November 6, 2010 by dantan
cwt Posted November 6, 2010 Posted November 6, 2010 I took my Marantz PM-KI Pearl integrated amplifier to Simply Hi Fi today, and just as I guessed, not a whisper at all from it. I could not get it to hum whatsoever.I took it home and Pierre kindly lent to me a Cow King (no, really, it's called "Cow King") digital voltage readout. I plugged everything back in and yes, the hum was still there - very softly but still there. I plugged in the Cow King and it was showing about 241-244V. I went out earlier and came home, and put my ear close to my amplifier and it was humming louder than during the day. I plugged in the Cow King, and it was reading 250! I plugged it into another power outlet at another location in my home, and it also read 250! Dan. Found this at whirlpool [posted october 16] Dan ; its your power supplier to blame ; WA is a special case it seems As I've mentioned a couple of times in other threads, this is the Australian Standard but does not hold true in WA yet where Western Power has advised it may take a few years to reach the 230v +10/-6/. In the meantime we continue to produce within the parameters of the Electricity Act 1945 – 240v +/-6%.Although 240v is the standard, mine, in a normal Perth suburb, has ranged between 248-251 recently. In some regional areas it can be up to 260v. As the OP is in Perth, I thought they might be interested as the system voltage here could be up to 30v higher than SA, and will almost certainly be at least 20v higher.
CCRider Posted November 7, 2010 Posted November 7, 2010 (edited) Hi guys,Firstly, apologies if this has been discussed before. The other night, I noticed some humming out of my Marantz PM-KI Pearl 2-channel Integrated Amplifier, while I was removing a Blu-ray Disc out of my Blu-ray Disc Player (which is placed in the shelf rack just below). It is fairly quiet but does get louder at times (usually when I've played material quite loudly and it's been pumping out a fair bit of power). I must stress that I cannot hear the humming unless I am within about 15 centimetres from the PM-KI Pearl unit itself. Most of the time, it's only a soft continuous hum that I can hear when 15cm or nearer to it. I was just wondering if humming is natural for amplifiers. Occasionally, the hum completely disappears but most of the time, it's a soft continuous hum. Dan. DeJa Vu I am experiencing the same with my Cambridge Audio 840C CDP. Very low level hum sourced from toroidal transformer. I emailed CAMBRIDGE AND WAS TOLD IT IS NORMAL (hit caps accidently) for the transformer to have a slight low level hum. Anyway given it is still under warranty I am having it replaced. The Elektra which has a massive toroidal transformer is dead silent and is on the same AC power run. The other thing to be mindful of is that even if it appears to be quiet at the retailers premises the ambient noise will probably never be as silent as it is at home. Background noise levels are deceiving. I found that out at my place. At say 2am in the morning the humming sounded relatively louder than it did than when it was "silent" during the day where it was almost inaudible. Edited November 7, 2010 by CC Rider
myrantz Posted November 7, 2010 Posted November 7, 2010 I took my Marantz PM-KI Pearl integrated amplifier to Simply Hi Fi today, and just as I guessed, not a whisper at all from it. I could not get it to hum whatsoever.I took it home and Pierre kindly lent to me a Cow King (no, really, it's called "Cow King") digital voltage readout. I plugged everything back in and yes, the hum was still there - very softly but still there. I plugged in the Cow King and it was showing about 241-244V. I went out earlier and came home, and put my ear close to my amplifier and it was humming louder than during the day. I plugged in the Cow King, and it was reading 250! I plugged it into another power outlet at another location in my home, and it also read 250! Cow King......... Bear in mind domestic meters could be inaccurate (no calibrated and all).... The problem I suspect is not the voltage output (after all, more = better, as long as it's not too much )... I'm guessing the power is probably not "clean" enough, may have a DC in there somehow.... Western Power just gave themselves pay raises, f**k the network, and raised our bills... Nothing we can do about it I gues, but maybe a Thor PS 10 or Belkin PF thingy may help? Another option (which I'm thinking for myself also) is to add in a new line from the meter box...
dantan Posted November 7, 2010 Author Posted November 7, 2010 Found this at whirlpool [posted october 16] Dan ; its your power supplier to blame ; WA is a special case it seems Thanks mate. Unfortunately, in WA, we lose out in every case, it seems. Always last to implement standards.
dantan Posted November 7, 2010 Author Posted November 7, 2010 DeJa VuI am experiencing the same with my Cambridge Audio 840C CDP. Very low level hum sourced from toroidal transformer. I emailed CAMBRIDGE AND WAS TOLD IT IS NORMAL (hit caps accidently) for the transformer to have a slight low level hum. Anyway given it is still under warranty I am having it replaced. The Elektra which has a massive toroidal transformer is dead silent and is on the same AC power run. The other thing to be mindful of is that even if it appears to be quiet at the retailers premises the ambient noise will probably never be as silent as it is at home. Background noise levels are deceiving. I found that out at my place. At say 2am in the morning the humming sounded relatively louder than it did than when it was "silent" during the day where it was almost inaudible. Thanks Crist. I suppose that it is a good idea to have it replaced, anyway, if nothing else, for a peace of mind. I certainly have been extremely happy with the performance of the unit. It is obviously inaudible when playing any material. I suppose it is just an annoyance for me, that's all.
dantan Posted November 7, 2010 Author Posted November 7, 2010 Cow King......... Bear in mind domestic meters could be inaccurate (no calibrated and all).... The problem I suspect is not the voltage output (after all, more = better, as long as it's not too much )... I'm guessing the power is probably not "clean" enough, may have a DC in there somehow.... Western Power just gave themselves pay raises, f**k the network, and raised our bills... Nothing we can do about it I gues, but maybe a Thor PS 10 or Belkin PF thingy may help? Another option (which I'm thinking for myself also) is to add in a new line from the meter box... Thanks mate. I shall certainly consider a few things, including a power conditioner. Or I might just live with the hum. It certainly doesn't seem to affect audio performance, whatsoever.
dantan Posted November 8, 2010 Author Posted November 8, 2010 Below is an excerpt from Plinius' web-site: MECHANICAL NOISE: Some items of equipment can directly radiate a mechanical hum or buzz. This mechanical noise almost always originates from the device's power transformer. Place your ear close to each component of your system and listen. If you hear a hum or buzz coming from within your equipment, then the noise is mechanical. 'Lamination rattle' occurs in all transformers to some degree, related to the quality of the transformer and the quality of the line voltage. If the noise intensity varies depending on the time of day, sometimes even the time of month, then it is due to the quality of the AC supply voltage in your area. In this case you're at the mercy of your energy provider. Well, looks as though I am "at the mercy of my energy provider", then. D'oh!
betty boop Posted November 8, 2010 Posted November 8, 2010 Dan as mentioned, Anthony michaelson of musical fidelity when interviewed by aus hifi and asked what the challenges are with the Aussie market. He said one thing. The power of western Australia. He said it's too high and too dirty ! Like any manufacturer I suppose they can make something to handle variations to standard. But a bit hard if the power company can't keep to the standards !
myrantz Posted November 8, 2010 Posted November 8, 2010 Below is an excerpt from Plinius' web-site: From what I understood (may well be misinterpreted), it'd need to be a DC in the line for the transformer to hum? BTW, did ur old NAD and Marantz pre hum in the past?
dantan Posted November 9, 2010 Author Posted November 9, 2010 From what I understood (may well be misinterpreted), it'd need to be a DC in the line for the transformer to hum? BTW, did ur old NAD and Marantz pre hum in the past? No, mate, I certainly never noticed any humming from my Marantz AV8003 Surround Processor/Pre-amplifier or NAD M25 7-channel Power Amplifier.
dantan Posted November 9, 2010 Author Posted November 9, 2010 Dan as mentioned, Anthony michaelson of musical fidelity when interviewed by aus hifi and asked what the challenges are with the Aussie market. He said one thing.The power of western Australia. He said it's too high and too dirty ! Like any manufacturer I suppose they can make something to handle variations to standard. But a bit hard if the power company can't keep to the standards ! Thanks Al. I think I shall just have to accept that in Western Australia, we will always be behind and lose out to the rest of the country!
myrantz Posted November 9, 2010 Posted November 9, 2010 No, mate, I certainly never noticed any humming from my Marantz AV8003 Surround Processor/Pre-amplifier or NAD M25 7-channel Power Amplifier. Since you have found a power point that wouldn't hum, why not use that as a source instead? Too far? Thanks Al. I think I shall just have to accept that in Western Australia, we will always be behind and lose out to the rest of the country! Try the world... Ironically that's what I like about WA really... Isolated, slow, laid back, relaxed .
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