jackpollard Posted October 15, 2012 Share Posted October 15, 2012 Hello All; I changed out my caps about 3 weeks ago with the Crites kit in my Cornwalls. Did not have any issues. Today I notice a buzz in my right speaker. Swapped all cables, changed inputs, changed power cords, ect. The hum is in the right speaker regardless of source. So, could a cap cause a buzz? I will check them all tomorrow. Maybe my solder job was crappy. Jack Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted October 16, 2012 Share Posted October 16, 2012 Swapped all cables, changed inputs, changed power cords, ect. Try another amp before messing with the speakers again. Quote Link to comment Share on other sites More sharing options...
jackpollard Posted October 16, 2012 Author Share Posted October 16, 2012 Funny thing. I sold all my other audio equipment because I found audio nirvana. I will switch speakers. I have a pair of VR3s that were just too big to ship. I sure hope its not my amp. Thanks for suggestion. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted October 16, 2012 Share Posted October 16, 2012 you could swap crossovers to rule out the amp and see if the buzz follows the crossover, right? Quote Link to comment Share on other sites More sharing options...
jackpollard Posted October 16, 2012 Author Share Posted October 16, 2012 you could swap crossovers to rule out the amp and see if the buzz follows the crossover, right? I thought I had done that when I swapped the right and left inputs and nothing changed. But, that would not of shown right and left x-ovrs. So, I'm going to switch speakers when I get home. That should be pretty telling. If no sound, speaker, if hummmmm well amp. And, let me be clearer, it was more a hummmmm then a buzz really. A very deep low level hum. I'm hoping its not a tube. I will re-seat them all also. Thanks!! Quote Link to comment Share on other sites More sharing options...
garyrc Posted October 21, 2012 Share Posted October 21, 2012 And, let me be clearer, it was more a hummmmm then a buzz really. A very deep low level hum. I'm hoping its not a tube. I will re-seat them all also. Hmmm (couldn't resist). Is it a 60 Hz hum? That would sound moderately deep. I think 60 Hz is about the frequency of the second B up from the bottom on the piano (check online). In comparing, try to ignore the higher overtones of that B on the piano (zingy, twangy, richer, higher frequency sounds). Although hum usually sounds like a fundamental frequency only (60 Hz), sometimes a 60 Hz hum is mixed with one that is one octave higher (120 Hz), but no midrange or treble frequencies, in my experience. It could be a ground loop that you just acquired (search forum and internet for remedies). Are you in a different room with a different pattern of ac wiring, a different power strip, etc., than you were before you put in the new crossover? Turn everything off, and check to make sure all interconnects are intact and fitting tight. I tend to doubt that is the crossover. Good Luck. Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted October 21, 2012 Share Posted October 21, 2012 Have you possibly added any CFL's Compact Flourescents? Depending on the manufacturer, some can create static (Hum) to your system. Just a thought as most Power Company's are giving them away now....... Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted October 21, 2012 Share Posted October 21, 2012 Is the buzz coming from the SPEAKERS or the cabinet? Sometimes it is hard to tell... If it is coming from the cabinets, then maybe the crossover board is not snugly mounted, or maybe the speaker back is not completely secured...and sometimes the original coonector on the speaker back needs tightening, too! Just a thought! Buzz and hum are two different sounds, and hard to tell what your issue is without actually hearing it. Quote Link to comment Share on other sites More sharing options...
jackpollard Posted October 21, 2012 Author Share Posted October 21, 2012 Again thanks for all suggestions and thoughts. I swapped each tube with its opposite, changed left 300b with right, no change. I changed electric sockets and no change. I ruled out the speakers based on changing the IC's at the amp end only. It follows the right RCA plug, not speaker. I have a Radio Shack sound level meter that I pulled out. I sat down next to the speaker and used it. It is definitely emanating from the woofer. Now on the Hogan, there are 'hum' knobs. When I slowly turn them, I actually hit a sweet spot where the hum is lowest I put the meter on 60 and can get it to register 0, but that does not mean its noiseless. I'm not 100% sure what the 60 or numbers relate but I will look that up. The hum knobs are around 11:00, anything more or less brings more hum. What exactly do the hum knobs do? When I play music I don't seem to hear it. But when its quiet I do. I can live with it, but I sure want to know what it could be. Thanks!!! Quote Link to comment Share on other sites More sharing options...
LarryC Posted October 21, 2012 Share Posted October 21, 2012 I'm late to catching up with the reading party, but have you switched speakers and does it stay on the same side regardless? Does it fluctuate if you rotate the speaker? These questions are directed at the possibility that you have a strong external, nearby EMI field picked up by the speaker crossover coils or perhaps your electronics on that one side. Prelim question: is it still there when the amp is off? Quote Link to comment Share on other sites More sharing options...
jackpollard Posted October 21, 2012 Author Share Posted October 21, 2012 Thanks for asking the questions; I think I ruled out the speakers. When I change the amp end speaker cables, the hum moved with the cable. So I switched the right speaker cable at the amp end to the left and left to right. The hum moved to the left speaker. The hum goes away when the amp is off. I checked all electrical and all sockets seem ok. Thanks again!!! Quote Link to comment Share on other sites More sharing options...
Marvel Posted October 21, 2012 Share Posted October 21, 2012 Now on the Hogan, there are 'hum' knobs. Those are balance pots for the directly heated triode (300b). I have them on my Welborne Labs Moondog 2A3 amps. I have a little low level hum, but havestarted to adjust each time I power them up, after they have been on a few minutes. To be honest, once the music starts, I don't hear it at all... []Bruce Quote Link to comment Share on other sites More sharing options...
jackpollard Posted October 21, 2012 Author Share Posted October 21, 2012 ] Now on the Hogan, there are 'hum' knobs. Those are balance pots for the directly heated triode (300b). I have them on my Welborne Labs Moondog 2A3 amps. I have a little low level hum, but havestarted to adjust each time I power them up, after they have been on a few minutes. To be honest, once the music starts, I don't hear it at all... Bruce Bruce; Exactly what I have, low level hum and when the music plays I don't hear it. Thanks for explaining the hum pots. If you turn off the music after listening for awhile, do you still hear the hum? I'm OK with it, wish it was dead silent of course, but can live with it as long as it will not ruin the amp. Thanks again!!! Quote Link to comment Share on other sites More sharing options...
garyrc Posted October 21, 2012 Share Posted October 21, 2012 Bruce; Exactly what I have, low level hum and when the music plays I don't hear it. Thanks for explaining the hum pots. If you turn off the music after listening for awhile, do you still hear the hum? I'm OK with it, wish it was dead silent of course, but can live with it as long as it will not ruin the amp. Thanks again!!! Hum that measures 60 dB (reading 0 with the meter set for 60 dB) may be pretty loud, even if you don't hear it with the music on. Are you measuring the hum right at the speaker, or from listening position? If right at the speaker, it's probably O.K.. I think I remember that the hum from listening position, with the pre-amp volume control at music level with my old (McIntosh) tube amp measured about 35 dB with a wide range meter borrowed from SFSU. There was also audible hiss with both JBLs and Klipshorns. For hum, with the Radio Shack meter, you would read -10 (no needle deflection) when set for 60, for any level 50 or below. Back then, I noticed that the residual room noise, after turning the amp completely off was "20 something" dB. WIth my solid state gear (see below) and Khorns, there is virtually no hum, but a bit of hiss. My older NAD pre/pro hummed its head off, with the volume control all the way down, even though it met specs. They didn't expect spks as efficient as Khorns ... Quote Link to comment Share on other sites More sharing options...
jackpollard Posted October 22, 2012 Author Share Posted October 22, 2012 Garyrc; Interesting information, yes I measured with the Radio Shack meter basically touching the cover of the speaker. I will do a "seating" test, but I'm going to guess it won't even pick it up. When you move about 2-3' away its barely audible. But its such a low hum that you can tell when the amp is off. I'm beginning to think that the hum is somewhat normal for a SET amp. and I think I can live with it, as long as its not a sign of some major issues just waiting to drop. Jack Quote Link to comment Share on other sites More sharing options...
Marvel Posted October 22, 2012 Share Posted October 22, 2012 You could switch to DC for the heaters, but you would increase the complexity of the amp and 'may' change the sound. Depends on how much room is in the chassis, too. I pulled this off of a thread on the DIYAudio forums... If you do not wish to tolerate too much noise the choice is DC. Then design and voice the Amp to work well with DC. You can get as low as <0.3mV noise levels out of a sensibly implemented DC heated 300B Amp, or > 80db below 1 Watt.If a hum level around 50-60db below 1 Watt (which is the best achievable with AC Heating and non-extreme hum cancellation circuits) is acceptable to you (the average for AC Heated SE Amp's with 2A3 and 300B is around 3-5mV) then go AC and voice the Amplifier to work well with AC. Bruce Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted October 22, 2012 Share Posted October 22, 2012 Many years ago, a friend who had replaced the woofer in one of the Heresys he had bought called me up and told me that there was a buzz in that speaker and we went through all the steps to isolate the source of it over the phone. He called me back later that nite and said he had done everything and it still appeared the problem was gonna be the woofer he had just installed. But, he was too tired to remove the back and he would do that the next evening. I called him the next evening and he said he still had the buzz, but it was not as loud and happened less often...and he would look inside the next morning (Saturday was the next day). I was in that area the next day, so I swung by his house and visited for a few minutes. He had not listened to the speakers since the previous evening, and still had not removed the speaker back to take the percieved bad woofer out. So we hooked everything up and listened to the Heresys for a few minutes...and the buzz started back up. He said "the buzz is still there, hear it?" I told him I did. Then he said "yep, that's what I was talking about on the phone the other night...but it is nowhere near as loud as it was then." I told him, "Let's look inside the cabinet." So we turned everything off, unhooked the speaker wires, and I laid the Heresy face down on the carpet to take off the speaker back and the buzzing started up again for a few seconds. Well, my curiosity was piqued, now, so I quickly removed the screws and as I lifted out the speaker back, a big horsefly charged out the back of the cabinet and almost hit me in the head making its escape! [^o)] Quote Link to comment Share on other sites More sharing options...
jackpollard Posted October 22, 2012 Author Share Posted October 22, 2012 Many years ago, a friend who had replaced the woofer in one of the Heresys he had bought called me up and told me that there was a buzz in that speaker and we went through all the steps to isolate the source of it over the phone. He called me back later that nite and said he had done everything and it still appeared the problem was gonna be the woofer he had just installed. But, he was too tired to remove the back and he would do that the next evening. I called him the next evening and he said he still had the buzz, but it was not as loud and happened less often...and he would look inside the next morning (Saturday was the next day). I was in that area the next day, so I swung by his house and visited for a few minutes. He had not listened to the speakers since the previous evening, and still had not removed the speaker back to take the percieved bad woofer out. So we hooked everything up and listened to the Heresys for a few minutes...and the buzz started back up. He said "the buzz is still there, hear it?" I told him I did. Then he said "yep, that's what I was talking about on the phone the other night...but it is nowhere near as loud as it was then." I told him, "Let's look inside the cabinet." So we turned everything off, unhooked the speaker wires, and I laid the Heresy face down on the carpet to take off the speaker back and the buzzing started up again for a few seconds. Well, my curiosity was piqued, now, so I quickly removed the screws and as I lifted out the speaker back, a big horsefly charged out the back of the cabinet and almost hit me in the head making its escape! LOL, Must be where the word "Debug" came from !!!! Quote Link to comment Share on other sites More sharing options...
garyrc Posted October 23, 2012 Share Posted October 23, 2012 Well, my curiosity was piqued, now, so I quickly removed the screws and as I lifted out the speaker back, a big horsefly charged out the back of the cabinet and almost hit me in the head making its escape! Which is why Klipsch has those little bug screens in the throats of some horns. I'm assuming the horsefly was deaf by the time it was released. See if the hum goes away when your refrigerator goes off (try unplugging it) ... same with florescent lights, non-HT dimmers, etc. Quote Link to comment Share on other sites More sharing options...
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