johnny_fever Posted March 20, 2009 Share Posted March 20, 2009 Hi, My new to me K Horns seem to have a slight hum at idle. I can hear this coming from the tweeter & mid. Is this normal? I'm using a Sansui Ba-5000 Amp & Ca 3000 Pre Amp. I had the Sansui hooked up to a pair of AR-9's that are dead silent at idle. The dc offset is 3 MV on both channels. The unit is plugged in to a dedicated circuit. It gets worse If I ground the amp. I reversed the power plug & no difference. I tried turning off all lights & no difference. I guess these speakers were built in 1995. Any help would be great. Thanks Rick Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted March 20, 2009 Share Posted March 20, 2009 K-horns are high efficiency speakers. They are very sensitive speakers. If you have a TV signal hooked up to your sound system that could cause a hum. It could also be other things. Search the forum for "hum" and I'm sure all kinds of great ideas for hunting it down will come your way. Quote Link to comment Share on other sites More sharing options...
twistedcrankcammer Posted March 20, 2009 Share Posted March 20, 2009 Hi,My new to me K Horns seem to have a slight hum at idle. I can hear this coming from the tweeter & mid. Is this normal? I'm using a Sansui Ba-5000 Amp & Ca 3000 Pre Amp. I had the Sansui hooked up to a pair of AR-9's that are dead silent at idle. The dc offset is 3 MV on both channels. The unit is plugged in to a dedicated circuit. It gets worse If I ground the amp. I reversed the power plug & no difference. I tried turning off all lights & no difference. I guess these speakers were built in 1995. Any help would be great. Thanks Rick Your Corner Horns are not creating the hum, it is in the system somewhere. Another possibility is to check if you have your speaker wire laying across or close to your interconnects. The K-Horns will also pick up on any amp problems you may be starting to have, before other speakers will. If they don't have a good signal going in, they will show that a problem exists, that is exactly what they are doing. Roger Quote Link to comment Share on other sites More sharing options...
johnny_fever Posted March 21, 2009 Author Share Posted March 21, 2009 Thanks Guys, I will look at it again in the AM. The speaker wires run behind 1 of them. Thanks Rick Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted March 21, 2009 Share Posted March 21, 2009 Do the speakers make a slight "pop" when the BA/CA is turned on with volume down to the "-70"? And is it both speakers or just one. There could be a number of reasons. What is odd is that when you ground the amp (using the phono grounding jack screw?) it gets worse. Try changing the phono pre-amp setting (move that switch from 50k to 100k, etc.) and see if the hum gets better or worse. It could be in the phono section. When was the last time you had the BA & CA serviced? I have a bunch of AU-11000's and after 30+ years, I ended up replacing resistors, caps, DC offset adjusted, seriously cleaned and all pots lubed, etc. etc., etc. Work was all done by a www.sansui.us recommended tech "guru". Results were phenomenal and pretty much ended some pesky idiosyncracies that the amps had developed over the years. Like hums, hisses, pops, crackles, drop out when using tone controls, etc..Now they are dead silent at an idle. Quote Link to comment Share on other sites More sharing options...
johnny_fever Posted March 21, 2009 Author Share Posted March 21, 2009 Thanks for the reply. The Slight hum is on both channels. DC Offset is 3 MV on both channels. The unit has never been serviced. I posted this ? on the Sansui / AudioKarma site. The hum is there weather the pre amp is on/off connected or disconnected. I will try the phono adj next. thanks Rick Quote Link to comment Share on other sites More sharing options...
russ69 Posted March 21, 2009 Share Posted March 21, 2009 Some amps will have some hum, you probably didn't hear it with the AR-9's. Good luck. Thanx, Russ Quote Link to comment Share on other sites More sharing options...
johnny_fever Posted March 21, 2009 Author Share Posted March 21, 2009 The hum is faint but there. Might not be a problem at all. I just could not elimanate it with some basic tests. The problem is moving this heavy stuff for testing. Thanks Rick Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted March 21, 2009 Share Posted March 21, 2009 I have a very slight hiss from the tweeter and mid range, but I practically have to have my ear right up against the grille. At a couple of feet away, I can't hear it. So, no worries. Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted March 21, 2009 Share Posted March 21, 2009 Rick, If they have never been serviced, you might want to seriously consider having a competent tech do a service and general cleaning. The BA/CA are rare as hens teeth and if you are going to keep that combo, it would be well worth it to have both components gone through. I have two sources that I can refer you to for Sansui integrated amps. tim@bristolnj.com Bristol Electronics wbendler@sbcglobal.net Bendler Electronics Both do superb work. Quote Link to comment Share on other sites More sharing options...
johnny_fever Posted March 21, 2009 Author Share Posted March 21, 2009 Thanks for your time. I got this amp in Sep along with the CA-3000 & TU-9900 tunner. All in mint condition. I was told by many to recap the amp (Audio Karma) I don't want to ship this 108lb amp. I was going to look into some Chicago tech's. Thanks Rick Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted March 21, 2009 Share Posted March 21, 2009 Warren is in South Euclid, Ohio (near Cleveland I-90). 5 hours away? Quote Link to comment Share on other sites More sharing options...
johnny_fever Posted March 21, 2009 Author Share Posted March 21, 2009 Warren as in DR*Audio? Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted March 22, 2009 Share Posted March 22, 2009 No, it's Warren Bendler (See www.sansui.us) , Bendler Electronics. He specializes in vintage Sansui. Quote Link to comment Share on other sites More sharing options...
johnny_fever Posted March 22, 2009 Author Share Posted March 22, 2009 Thanks for the info. Later Rick Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 22, 2009 Share Posted March 22, 2009 an amusing view on the hum buzz subject http://www.videomaker.com/article/8070/ Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 27, 2009 Share Posted March 27, 2009 Try this. Disconect everything except amp, preamp, plus 1 source such as a CD player. Plug everything into a single powerstrip and use 3 to 2 prong cheater plugs on every component.........as a test only. The hum may be gone if a ground loop is involved. The 3 to 2 prong cheater plugs could be unsafe if you are not using a GFI outlet and are suggested only as a temporary test to lift grounds between components. I am not familiar with your driving equipment. You mention the DC offset. Are these tube units? Khorns are very efficient. The hum has always been there, you just couldn't hear it through your less efficient speakers. Welcome to Klipsch. They will either get you to clean up your system........, you'll accept noise, or you'll find you are not a Klipsch guy. I am a noise freak. I hate hum, buzz, hiss, and have chased that stuff out rather than use lesser speakers..............for the last 31 years. So get going........ Quote Link to comment Share on other sites More sharing options...
johnny_fever Posted March 28, 2009 Author Share Posted March 28, 2009 Thanks for your time. The amp alone (No Input) makes the hum, The 1975 Sansui Amp has a 2 prong plug. The hum gets worse when I ground the unit. The guys on Audiokarma belive the problem is a bad power supply cap. Here is a link with pics & specs of the Sansui Ba-5000 Amp. Thanks Rickhttp://www.classicaudio.com/forsale/san/BA5000.html Quote Link to comment Share on other sites More sharing options...
mark1101 Posted March 28, 2009 Share Posted March 28, 2009 Well that would explain it. Glad you have it figured out. Quote Link to comment Share on other sites More sharing options...
garyrc Posted March 29, 2009 Share Posted March 29, 2009 Hope you find a way to decrease the hum, and you are getting what sounds to me to be good advice. With any set of electronics at idle, the Klipschorns would potentially reveal much more hum and hiss than the AR9s, but if the hum / hiss is far below audibility on the AR9s, it might be just barely audible -- up close -- on the Klipschorns. I think I remember that the AR9s have a sensitivity of somwhere between 87 and 90 dB, and the Klipschorns have been rated very, very conservatively by some reviewers at 98 dB, and are speced by Klipsch at 104 or 105 dB (depending on the year) when in a trihedral corner -- where they need to be. So at a minimum, you would get about 8 dB more hum/hiss from Klipschorns, and probably more like 14 dB more. That doesn't mean that objectionable hum/hiss is inevitable, though. My history with my Klipschorns looks like this, at amplifier idle: With McIntosh 40 wt tube amp and McIntosh c 28 preamp: some hum / hiss, but ignorable. With Luxman L 580: no problem unless I stood right in front of -- a few inches away from -- one of the Khorns. The preamp section of the L 580 and a Yamaha 135 wt power amp: only a problem when within a few inches. With a NAD T 163 home theater type preamp control center and NAD 272 power amp: considerable hum, and they hissed like puff adders in heat. The power amp was totally quiet -- all the noise came from the T163, from between the volume control and the preamp output, which meant that turning up and down the volume made no difference. The T163 was checked out at the factory and pronounced normal. The solution was to turn down the input pot on the power amp by about 6 dB, which suppressed the noise of the post volume control sections of the T163, and then I turned up the preamp control center. Now there is a barely perceptible level of noise at idle -- which some (young, healthy eared) guests can't hear until it is pointed out to them -- at any volume control setting that would not knock down the house when the music starts. Evidently a 6 dB difference in hum / hiss is quite a lot when dealing with thresholds or near thresholds! Having had Klipschorns, other Klipsch speakers, JBLs, ARs, Infinities, BBC specials (name?) and a few others that didn't stay long, I can say that Klipschorns seem to be the most revealing of anything fed into them. The JBLs came in second. With good recordings and properly functioning electronics, revealing is a good thing. But the warts do show. Quote Link to comment Share on other sites More sharing options...
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