No, I did not get that done. The city however has told me they will not do anything about the hum problem as I do not have a voltage problem as far as they're concerned. I thought the iso tranny would help kill any noise coming from the main transformer? Any ideas? |
I guess I could use some help clearing my head:-). What should I do next? The iso tranny didn't work, the electric company seems to think there is nothing wrong with the transformer, no amount of Quietlines or Enacom filters seem to have any effect. How do I stop this hum??? It's driving me freakin' nuts. The electrician will not hook up an outlet in the manner Nerspellsner describes because he says it would be against the law, a felony I believe. Granted it would only be for a few minutes but he's not going to do it. I really don't know what else to do. Any help to offer? |
Hi,
Thanks for all the info and ideas. Although I'm pretty sure I had already tried lifting the grounds on everything but the preamp, I tried it again, but the hum persists. Considering that the speaker will hum even if it is not connected to anything, only plugged in to the wall to power the subamp, it seems unlikely/impossible to be a ground loop associated with the rest of the equipment.
I have been researching the subpanel/isolation transformer idea for a month or two now and managed to pick up a 5Kva Topaz transformer on the cheap, so I'll probably go this route at some point in the near future.
I suppose I'll need to call the utility co. and ask them to replace the transformer leading to my house. Is this something I'm likely to meet resistance with?
With respect to Gs5556's response, What does EMI/RFI sound like? Kind of naive question I guess, but does it sound like 60Hz hum? What differentiates it? Second, I do have cable and I remember the installation guys hooking up some kind of grounding to my electrical panel, but I think it's mounted to the outside of the box. There is no cable hooked up to any part of the stereo however. And last, I did actually disconnect the water pipe ground a while back to see if it would make any difference, but it didn't. I never tried disconnecting the other ground though while leaving the water pipe connected so I'll give that a try.
I really appreciate everybody's help!
Matt |
Nsgarch,
It's actually a 300W Class A/B solid state amp. If it was only the sub amp then the midrange and tweeter shouldn't be effected according to Kevin at VSA. We'll see...
Matt |
The power company made it out today and although they couldn't find a voltage problem they installed a data recorder and said they'd be back in a few days. They agreed that the transformer was very old and possibly undersized as well. He said they would turn in a work order to replace it after they finished recording it's activity. Fairly positive visit, but we'll see how it turns out. Sometime next week my electrician is going to come over and install the iso transformer as well so pretty soon I should have an answer. Thanks for your help so far and I'll let you know how things work out. |
The electric company let me down. They said that, although my voltage did drop below 120V when the A/C turned on, it was otherwise operating normally. They also said that noise on the line was not their problem and they weren't willing to use their resources to track it down. They suggested getting a "Starter Kit" for my A/C, but I know nothing about these so I'll have to do some research. They offered no real help with the hum. I'm going to try and schedule some time with the electrician to install the Iso tranny and see if that helps. After that I'll try and run the Romex thru metallic tubing that I ground to the subpanel. Eventually, I may solve this:-). |
I'm hoping the isolation transformer will help with the noise. The electrician is coming over Thursday night to do a test hook-up and see what happens. The starter kit is something I know nothing about, but if it will stop my lights from dimming I'm all for it. Before I start the search do you have any suggestions/explanations that could point me in the right direction? |
Well, we hooked up the Isolation Transformer today and the hum was still present. I guess the only thing I haven't been able to try yet is ruling out RFI. Is there any way to check for this without spending a lot of money? |
Thanks Nerspellsner! I didn't understand clearly before what you meant. I will ask my electrician about it and hopefully get him to come out and give it a try. |
Forgot to answer your questions...I have only one main panel. When we hooked up the transformer we used a subpanel in a temporary arrangement, but I wanted to try it before permanently installing it. The main breaker is in the panel, not the meter socket. |
I ruled out the speakers today. Borrowed a friends and they hummed too. Next step is to find out if it's the city or the house. |
No TV or cable anywhere near the system or connected to it in any way. I couldn't tell you whether it's 60Hz or 120Hz. I've listened to it pretty carefully and would swear there is a rythm to it of about 4 beats per second, but other than that I don't know. A mic and scope would be nice, but unlikely I can find one to borrow. What would the difference be as far as what's wrong if it's 120Hz vs. 60Hz? |
Hifi57,
The topaz can step 240 down to 120 as far as I know. I believe we hooked it up that way at one point. We tried various connections, even wiring it for balanced output. What/How would grounding, or floating the ground, on the output side tell us about the service transformer?
Matt |
That wouldn't make any sense because when the power amp and speaker cables are disconnected, and only the speaker is plugged into the wall, it will hum. You should re-read some of the above posts, as I'm sure they are confusing. At this point, I'm sure it's coming from the electricity and not my equipment. I still need to find whether it's coming to me from the city, or something that happens after it arrives in my house. Hopefully soon, I'll have some more answers. |
Hi Sherod,
Well, yes, but not in the way I thought I would. I can't count the number of times I had my friend Terry, who is an electrician, over to the house to try whatever I had read about in an effort to kill the noise. In the end, it never made any difference, well, that I could tell at least.
Then, I replaced my preamp and phono stage with Raul's Essential 3150 Phono/Line preamp, and all the noise went away. Actually, not all of it, if I put my ear within a few inches of the driver I can still hear a tiny bit of noise, but I think that's fairly normal and it definitely doesn't bother me or become audible from the listening position.
I have to tell you that this makes no sense to me. In the posts above I described unplugging everything in the system and disconnenting the speaker cables so that I could effectively isolate one speaker. I then plugged in the sub amp of just the one speaker with nothing else attached. This still resulted in the same amount of noise, but only thru the woofer, because the mid and tweeter were not recieving any signal/power. Since this, I presumed, meant it wasn't any of the other equipment, or a typical ground loop problem, I focused my attention on the electrical power coming to/thru the house. Nothing I tried, however, worked.
So, I have no idea why changing to the Essential fixed the problem, but it did and I can only tell you that I popped one of my best bottles of wine that night and sat there alone listening to the silence between songs in total amazement/relief/bewilderment until I was not thinking clearly anymore and called it a night:-).
The Essential does run fully balanced and now everything in the system, except the CD player, runs balanced connections as well, including my tonearm, so perhaps that has something to do with it. The power supply on the Essential is a fairly sophisticated beast and very well could be responsible, but ultimately I have given up trying to figure out why and have happily accepted the result.
There are a couple of threads in the Analog forum that discuss the Essential 3150 if you're interested. Mine is not the only system that got quieter after installing it according to at least one post. Needless to say I'm very happy with it!
Matt |
Can you tell us more about the filter you are using? |
