chepo61 Posted February 18, 2003 Share Posted February 18, 2003 Well I finally set up my new H/K 520 in a 6.1 configuration using a spare yamaha amplifier I had for the surround back channel. The only problem I have is that I'm getting noise through the yamaha amp, you can clearly hear a radio station coming through. I've changed the interconects and still the same problem. I've plugged the amp to an ac line filter I have and still the problem persists. I'm about to pull the hairs out of my head because of this, it is very annoying. Any suggestions ????? Thanks, Jose. Quote Link to comment Share on other sites More sharing options...
dougdrake Posted February 18, 2003 Share Posted February 18, 2003 Do you hear the noise when there is no input source connected to the Yamaha amp? Is it a dedicated amp, or is it a receiver or integrated amp? DD Quote Link to comment Share on other sites More sharing options...
chepo61 Posted February 18, 2003 Author Share Posted February 18, 2003 It is a stand alone dedicated amp. Since the H/K 520 has only 5 channels, I have it's pre outs, which give it a 6.1/7.1 configuration, connected to the yamaha so there is no source components connected to it, just the speakers for the surround back channel. Jose. Quote Link to comment Share on other sites More sharing options...
dougdrake Posted February 18, 2003 Share Posted February 18, 2003 In your case, then the source for the amp is the HK. Does it make the noise/sound when the HK is disconnected from the amp? Doug Quote Link to comment Share on other sites More sharing options...
chepo61 Posted February 18, 2003 Author Share Posted February 18, 2003 I'll have to check that when I get home today. I'll get back to you on it. And I really appreciate your feedback on this this issue. Jose. Quote Link to comment Share on other sites More sharing options...
chepo61 Posted February 18, 2003 Author Share Posted February 18, 2003 dougdrake, I just disconnected the yamaha amp from the H/K and the noise is still coming through, I can still hear that darn radio station. Any thoughts ? Quote Link to comment Share on other sites More sharing options...
Vladi Posted February 19, 2003 Share Posted February 19, 2003 Yes, some of your interconnects is not shielded properly. I had a similar situation, a radio station was coming thru my speakers, and found out that the interconnects comming from my PC into my receiver were the cause. Found that by unpluging in turn all interconnects. Of course the interconnects from the PC were el-cheapo! However, you might have a different problem. Quote Link to comment Share on other sites More sharing options...
WMcD Posted February 19, 2003 Share Posted February 19, 2003 1) I infer that the Yamaha was previously used in some application, and there was not a problem. Is that correct? 2) Now, just sitting there, powered up, with just the speakers connected, you hear the station through the speakers connected to the Yamaha. My guess this is an AM station with transmitter close to your location. 3) Try to get to condition 2) and let us know how things are going. If there are no input jacks connected to anything, then perhaps the radio signal is getting into the Yamaha through the speaker wires. I'm guessing that a change from 1) is that you added some longer speaker wires to make the run to the surrounds. Just a guess. 3.1) Sometimes, radio frequency waves can get into the amp via the speaker wires. It is my understanding that the negative feedback circuit is part of the path. 4) If I had the problem I'd try to diagnose the "speaker wires as antennae" theory buy plugging some headphones into the Yamaha with the speakers attached. This would work as a test if it possible to listen on the headphones and the speakers. I don't know if your amp allows that. It might be that the act of plugging in the headphones disconnects the speakers. 5) Let's assume the radio station can be heard on the headphones with the speaker wires attached. See if the radio station goes away when the speaker wires are disconnected. I'm assuming that the wires to the headphones are not an effective antenna. 6) If you determine that the speaker wires are the effective receiving antennae, the issue becomes what to do about it. 7) I would buy some 0.1 uF or 0.047 uF ceramic disk capacitors from RS. They used to carry these, anyway. Connect them across the speaker outputs of the Yamaha. They go in parallel with the speaker wires. 8) The disk capacitors should short out any RF at about 1 megahertz getting back into the amp. They have no effect at audio frequencies. Let us know. Gil Quote Link to comment Share on other sites More sharing options...
chepo61 Posted February 19, 2003 Author Share Posted February 19, 2003 ---------------- On 2/19/2003 8:59:17 PM William F. Gil McDermott wrote: 1) I infer that the Yamaha was previously used in some application, and there was not a problem. Is that correct? Before I bought the H/K I was using a yamaha RX-v2092 receiver. The stand alone amplifier was being used to passively bi-amp my RF3 II's having the stand alone feed the woofers and the receivers amp feed the tweeters. With this setup the problem was always present but given the fact that the stand amp alone was feeding the woofers of the RF 3II's the noise was not that noticable. 2) Now, just sitting there, powered up, with just the speakers connected, you hear the station through the speakers connected to the Yamaha. My guess this is an AM station with transmitter close to your location. I do have a radio station in the area about a couple of miles away but why didn't my previous yamaha receiver or my current H/K have/has this problem ? If indeed the radio station was being fed through the speaker wires wouldn't this type of situation be present with my current receiver ? 3) Try to get to condition 2) and let us know how things are going. If there are no input jacks connected to anything, then perhaps the radio signal is getting into the Yamaha through the speaker wires. I'm guessing that a change from 1) is that you added some longer speaker wires to make the run to the surrounds. Just a guess. My speakers runs were much shorter when I was using the stand alone amp in the bi-amping configuration. 3.1) Sometimes, radio frequency waves can get into the amp via the speaker wires. It is my understanding that the negative feedback circuit is part of the path. 4) If I had the problem I'd try to diagnose the "speaker wires as antennae" theory buy plugging some headphones into the Yamaha with the speakers attached. This would work as a test if it possible to listen on the headphones and the speakers. I don't know if your amp allows that. It might be that the act of plugging in the headphones disconnects the speakers. Unfortunatley my yamaha amp does not have a headphone jack. Would it be worth while buying the capacitors you mention and give it a try ? I have a RS in the area. I really appreciate your feedback on this matter. Jose. 5) Let's assume the radio station can be heard on the headphones with the speaker wires attached. See if the radio station goes away when the speaker wires are disconnected. I'm assuming that the wires to the headphones are not an effective antenna. 6) If you determine that the speaker wires are the effective receiving antennae, the issue becomes what to do about it. 7) I would buy some 0.1 uF or 0.047 uF ceramic disk capacitors from RS. They used to carry these, anyway. Connect them across the speaker outputs of the Yamaha. They go in parallel with the speaker wires. 8) The disk capacitors should short out any RF at about 1 megahertz getting back into the amp. They have no effect at audio frequencies. Let us know. Gil ---------------- Quote Link to comment Share on other sites More sharing options...
WMcD Posted February 20, 2003 Share Posted February 20, 2003 It would be interesting to confirm whether the local station is the source of the problem. You can probably figure it out by checking its broadcast frequency and listening on a radio to see if that program is, indeed, what is getting into the hi fi. What we're talking about is not too uncommon in the ham radio community. The ham, or even (yuck) CB transmissions would get into amps, phone lines, etc. I really should order an ARRL (ham society) book which addresses problems with radio frequency interference. It is not just real radio transmitters causing a problem. People have problems like a pop when the furnace motor turns on. There is a lot more RF hash and noise around the house than ever before. For example, you may have found that your computer or monitor makes so much noise that AM radio reception is impossible. Light dimmers, and flourescent lamps are other sources of problems. Some of the noise is on the a.c. line, some of it is radiation. I did have an intermittent problem with my audio installation when I lived close to a main street in Chicago. Cab drivers would communicate with each other via CB's. Every once in a while I'd hear the equivalent of "That a big 10-4 good buddy" in some language from the old country. It was not a consistent enough problem to make me work on it. Yes, I think the caps would be a worthwhile experiment. They cost about a buck a piece, maybe $2 at worse. The investment in the experiment is therefore a matter of a few dollars, and minutes. Naturally I can't guarantee anything. I'll check the local RS at lunch time to see what they stock. This varies from store to store. I may be able to find a standard stock number for you. At worst, they can be ordered. You may know that Nelson Pass makes some of the most well respected MOSFET amps in the industry. He also has published many projects for home construction. I noticed that he puts a 0.047 uF cap across the a.c. line in one project to keep out noise. Gil Quote Link to comment Share on other sites More sharing options...
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