Chicago_Pete Posted June 27, 2006 Share Posted June 27, 2006 I hope this isn't going to be too long but I want to post as much info that I can think of up front. My Klipschorns have had a hum since the day I purchased them. After swapping out numerous amps, solid state, tube, new and vintage amps, no improvement. Same thing goes for preamps. Cables, speaker and source did not help. ALK crossovers certainly helped the sound but not the hum issue. I disconnected the woofers and the hum disappears with just the tweeter and squawker playing. Time for some woofer service? Both channels were humming equally. Could both woofers need service? Is it just some Khorn thing that I have to live with? If thats the case, so be it. They still sound great! The best, Pete Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted June 27, 2006 Share Posted June 27, 2006 Ahh, the joys of high-efficiency speakers. If the hum is 60 cycle (or 120 or 180) then don't be too quick to blame the woofer. You are simply in its response region. Is the hum constant? Is the hum loud. What else is in the room? What else is on the circuit (this can include things out side the room? (A long extension cord from another circuit might help solve that) Since it is on both sides, it would be quite a coincidence that it was two bad speakers. It can be tracked down, just be methodical Good Luck, -Tom Quote Link to comment Share on other sites More sharing options...
LarryC Posted June 27, 2006 Share Posted June 27, 2006 Odd question, I know, but do the woofers still hum when you disconnect the speaker wires? Just curious, but it does happen in a strong EMI field, a puzzle of its own. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted June 27, 2006 Share Posted June 27, 2006 Under 2mV is enough to cause an audible hum on Khorns! Finding the reason can be maddening. I once fixed a source of hum in my systems by loosening, wiggling and retightening the connections on the whole house ground at the box and rod. Rick Quote Link to comment Share on other sites More sharing options...
Guest " " Posted June 27, 2006 Share Posted June 27, 2006 hum in both channels? Are we talking SS equipment or tube equipmnent? Have you had your electric service in that room checked? Need to check it on 2 fronts, one grounds and polarity, the other voltage drops. You can use one of those plug looking devices with the 3 led's on it to check you grounds and polarity. Voltage drops are tougher. In my case, I have a line conditioner that adds upto 11 volts to the power to get it to 120, it's on it's own service box, and my lines into the room are 30 amps. Power coming into the house in my area is bad. In your case, what else is on the power line you are using? Is there a power strip that could be suspect? You can also check you system with a multimeter. For the purposes of the test, have someone who is knowlegdeable with a multi meter and AC power check your amp for ground looping. One test is to put one lead of the AC volt meter on the metal chasis of your amp, ground screw would be perfect, place the other lead on the volt meter on a wire that runs out side to your cold water pipe. if you get a reading by doing this, you have a circut ground problem. very common in homes that use plastic insulated electrical runs as opposed to the metal coiled PBX cables. Before you go crazy hunting down grounds, circut faults, and looping issues, have you tried the amp in another room on a different circut, or at least can you run a long thick extenstion into that room and try to test with power from another room and different electrical run? Do you have another amp that can be used for testing? Quote Link to comment Share on other sites More sharing options...
SilverSport Posted June 27, 2006 Share Posted June 27, 2006 Pete, My 2005 AK-4 network with all new drivers/speakers K'Horn's have a hummmmm...I just thought it was Tubes...be they VRDs and BlueBerry or EICO HF-81... Bill Quote Link to comment Share on other sites More sharing options...
meagain Posted June 27, 2006 Share Posted June 27, 2006 The only hum problem I had was eliminated when Mark Deneen suggested to remove the grounds from the plugs on everything by using adaptors (for 2-prong). Didn't BS button have a long thread on hum? Do tubes hum also? I thought they just hissed. I have hiss but hum is gone. Quote Link to comment Share on other sites More sharing options...
RAPTORMAN Posted June 27, 2006 Share Posted June 27, 2006 Have you tried a cheater plug??? Easieist and cheapest solution for a ground loop hum. Home Depot's got them for $2. Quote Link to comment Share on other sites More sharing options...
J M O N Posted June 27, 2006 Share Posted June 27, 2006 Have you tried a cheater plug??? Easieist and cheapest solution for a ground loop hum. Home Depot's got them for $2. Kinda sounds like you might have a ground loop problem. Speakers don't hum, they just reproduce hums that are fed into them. Try the cheater plug suggestions. You would probably need to do this with all but one of your components. Quote Link to comment Share on other sites More sharing options...
Dale A B Posted June 27, 2006 Share Posted June 27, 2006 A friend of mine with Belle's had a hum that was traced to a dimmer switch on the same circuit. Did you try outlets on different circuits via an extension cord? Good Luck! NP - Govt Mule (Debut - 1995), via vintage Sansui S-930's Quote Link to comment Share on other sites More sharing options...
Chicago_Pete Posted June 28, 2006 Author Share Posted June 28, 2006 Hum update and more info. Thanks to all for the quick responses and suggestions. I tried a heavy duty extension cord in every outlet within 50 feet of my gear with and without a cheater plug. Hum is still present. I swapped out RCA and speaker cables, Monster, Audioquest, Kimber PBJ, and Radio Shack, no luck. Tried 5 different preamps, McIntosh C22, JM Blueberry, SAE Mark 1(solid state), and a pair of Philly Audios, no luck. Tried 5 different power amps, McIntosh MC30s, 2 ST70s, SAE Mark 3CM (solid state) and a McIntosh 2105, still humming. I even swapped out the ALKs for my 40 year old original crossovers without success. All of this gear cannot be equally bad. My vintage JBL speakers do not hum but they are way less efficient even though they have horns. The hum is pretty annoying at ide or between songs. The thing that really burns me is that I had an electrician run a dedicated line while I was building this room for 2 channel listening. Guess I need to get sparky back out here to test the power. Pete Quote Link to comment Share on other sites More sharing options...
tychicum Posted June 28, 2006 Share Posted June 28, 2006 er ... does anybody else besides you hear this hum?... have you tried making yourself a tinfoil hat ...? [6] Seriously it does sound like it might be environmental. It sounds like you have tried everything imaginable except ... maybe ... dragging the thing next door and trying it in a different environment. Quote Link to comment Share on other sites More sharing options...
meagain Posted June 28, 2006 Share Posted June 28, 2006 Say you have a power strip and all the gadgets running the speakers are plugged into that... Did you put adaptors on every plug in the power strip? Quote Link to comment Share on other sites More sharing options...
LarryC Posted June 28, 2006 Share Posted June 28, 2006 Is TV or cable in on this in any way? If so, you might need an isolation device. Quote Link to comment Share on other sites More sharing options...
edwinr Posted June 28, 2006 Share Posted June 28, 2006 As has been said before, speakers don't hum by themselves, so you can pretty much eliminate the Klipschorns as the culprit. One other suggestion is to check whether a power cable or even speaker cables are close to or lying on an interconnect. This will definitely cause hum. What's in your next room? Have you a refridgerator or something similar? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 28, 2006 Share Posted June 28, 2006 Do this.... Attach just the Khorn's to what ever amp floats your boat. Does it hum with just an amplifier? Just to be clear do not attach a preamp to the amplifier at all. Actually its best to make some RCA shorting jacks to short the input to the amplifier for this test since they could pickup stray noise in the room with nothing plugged into them. Report back what you find. Craig Quote Link to comment Share on other sites More sharing options...
Chicago_Pete Posted June 28, 2006 Author Share Posted June 28, 2006 In an act of desperation I took a ride to the local Radio Shack and dropped a quick hundred on a Monster Cable power strip. It did nothing to my surprise considering that the 17 year old who sold it to me assured me that it would cure my hum issue. Clean power he stressed! The Matrix will look great. Whatever that is? So per Craigs suggestion, I connected only my Mac 30s to the speakers without a pre. Ever so slight hum in the left channel, and non-existent in the right. The plot thickens. Quote Link to comment Share on other sites More sharing options...
tychicum Posted June 28, 2006 Share Posted June 28, 2006 In an act of desperation I took a ride to the local Radio Shack and dropped a quick hundred on a Monster Cable power strip. ... Hmmmm ... the old "Monster Cable" hummer ... Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 28, 2006 Share Posted June 28, 2006 In an act of desperation I took a ride to the local Radio Shack and dropped a quick hundred on a Monster Cable power strip. It did nothing to my surprise considering that the 17 year old who sold it to me assured me that it would cure my hum issue. Clean power he stressed! The Matrix will look great. Whatever that is? So per Craigs suggestion, I connected only my Mac 30s to the speakers without a pre. Ever so slight hum in the left channel, and non-existent in the right. The plot thickens. So is this ever so slight hum in just one channel way less or different then the hum out of both when the entire system is hooked up? If so do as Mark suggested and just attach your preamp to your amp with no sources then add each source until the real hum shows up. When it shows up you found the problem. I bet this is a ground loop problem or as suggested Cable TV or Satilite. Craig Quote Link to comment Share on other sites More sharing options...
D-MAN Posted June 28, 2006 Share Posted June 28, 2006 I agree - you need to float your ground - or go to a 2 prong adaptor on your amp. Quote Link to comment Share on other sites More sharing options...
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