Amp "Hum" caused by dimmer switches

I just recently got an Acurus 100x3 amp to drive the front 3 speakers of my home theater system and I am disapointed to find out that my room light dimmer switch is causing a very noticeable "hum" that can be heard from the listening position when no audio signal/ low passages are present. I did not have this problem using the amp in my harmon/kardon receiver. I do not want to remove the dimmer and go to an on/off switch and do not have the money for a power conditioner. Am I out of luck and have to resell the amp? I bought it used from this sight so I can not return it. The amp sounds very nice when the lights are not in use. I'd love to get some sound advice! Thanks!
I have the same problem with my audio system. My MonsterPower HTS3500 hums when I turn the lights(dimmer) on. I also get the hum when I turn on my pre-amp. I am pulling my hair out trying to find a solution to the problem. The only thing I can think of is the kitchen (with flourescent lighting) is nearby, and this is causing a hum in the AC line. You might try moving the amp to another room to see if you still hear the hum. A power conditioner may help, but as you can see in my case I have a similar problem even with the conditioner.
Before you give up, you should try the AudioPrism Quiet line filters. They look like battery eliminators for a CD player, often referred to as a wall wart.

Many household appliances (and especially dimmer switches) dump loads of noise into your electrical system. Even when the problem is not as obvious as in your situation, this noise creeps into every component in your sound system and effects performance. I had a totally quiet system, and bought a set of Quiet Lines at CES just for the experience. After having them in my system for a week, I removed them, thinking I could do just as well without. That idea lasted just about to the end of the next piece of music, whereupon I replace them and they have remained ever since.

These filters are inexpensive, and can be moved from one AC outlet to another, to determine the best results. They come in a pack of 8 pieces at retail $300.00. You should be able to find a dealer that would let you try a set over one weekend to see if they fix your problem. If they do, this would be less expensive than reselling and shipping the amp that you are otherwise happy with.
Albert- Are you using a line conditioner with the Quiet
Lines? I'm having a hum problem with my amp and I have a conditioner and dedicated line. I put the amp in my second system and no hum, so it's not the amp.The hum is local in the amp and goes to the speakers. Any ideas??
Try installing a better quality dimmer - some of the "better" ones have RFI filtration caps. etc. so they output less radiated noise back onto the AC lines. I had this same problem for years, & didn't discover the source until that old round-knob dimmer finally failed & was replaced. The new one is a toggle switch type, but price was comparable BTW. Also I have seen little filters available that you can install across the AC line input & line output. I don't know the manufacturer, but someone here probably does? It appeared to be a quality cap. & a series resistor package, something like 0.1uF in series with 47 ohms?
Also try an AC line conditioner - borrow one from a local dealer for audition. A Chang Lightspeed 3200 or etc. is not that expensive, cheap if bought used & resellable if no help.
I second the recommendation to upgrade your dimmer. Lutron makes a number of high quality wall box installable dimmers. I use 11 of their Diva Series units in my home. Even when they are all on, no hum. Other problematic items are diode (capslite) bulbs, anything with a high/low switch that uses a diode (will drive class b amps (usually subwoofer) crazy).

Another suggestions would be to use a different line to supply the audio system (or dimmer). Best would be a seperate dedicated audio line. Use a very low wattage bulb with no dimmer. Or if you want the ultimate no noise dimmer, replace the dimmer with a variac (variable autotransformer). They don't install cheap, but are silent.
The Lutrons are worth a try as is using a different circuit if you can. None of those worked for me, but shielded interconnects between the preamp and amp completely eliminated the hum for me. Now, it's not easy to find shielded interconnects that aren't a little muffled, but it was the only thing that worked for me, and I did find one that I like.
Khaki8 and Brentski71. Yes, I am using a line conditioner and have fourteen dedicated runs to my audio system as well. I did not have any noise problems before the line conditioner or the Quiet Lines, however there was a performance gain with each of these.

I witnessed an active demo showing Quiet Lines plugged into a noisy outlet on the main floor at CES, whereupon some very obvious buzz and hum was reduced to inaudible. This was what made me think about your situation. There were hundreds of electrical powered things going on, not to mention the lighting. I thought that if it worked there, maybe it would help you.

The comments by Bob bundus are probably correct. The quality of the dimmer is a likely source of the hum. I have no way of knowing which of you (could/ would?) replace this noisy dimmer yourself. Electricians fees and markup on parts could easily run half the price of a set of Quiet Lines. This is why I suggested getting a set for trial, before investing any money.

If you have no other source, I would let you try my filters and see if it fixes your problem. I would prefer shipment by air each way though, so I could return to normal pretty quick.
So where do you get Quiet Lines from?
Dimmers only cause problems when on. Turn it to the "off" position while listening. Problem solved.
I had the same problem when I installed a Krell 300i into my system. I started disconnecting interconnects,etc one at a time and it came down to the only piece that had a 3-prong cord which was ny new Krell at the time. Using a cheater plug cured the problem, but shortly thereafter I purchased a Tice Elite plc and no longer need the cheater. Now everything is real quiet.
If the dimmer is the problem, you should remove the dimmer, no line conditioning treatment is as good as removing the source of the problem altogether. Try getting a few lamps for the room to give you different levels of total lighting in the room. If you guys really want to hear how bad dimmers are for your system, turn a clock radio to an AM station and then turn your dimmer up and down. If you really must have a dimmer, get one of the stepped dimmers, as a fixed resistor does less damage than a variable resistor, but still damage. For the record, I have no dimmers in my entire house, one dragged out argument with my wife, and years of improved listening as a result, well worth it.
Several comments on this one.

14 dedicated lines for an audio system ??? Talk about the potential for a ground loop !!!! That would have to be done very carefully. I'm assuming that Albert probably paid as much attention to having this done correctly as he does to putting forth well written and informational posts though. WHEW !!! That one's pretty much a complete breaker box unto itself !!!

Hum, ground loops and noise can be generated from having pieces of gear within the same system plugged into different outlets. This is true EVEN if they are on the same circuit. Try plugging everything into one outlet via a power strip, etc.. and see if that helps at all.

If you have ANY two pronged power cords hooked up in that system that are not polarized, you might try flipping them around. This can sometimes make a dramatic difference in noise coming into the system and lower the noise floor of the equipment itself.

You might want to invest in a polarity checker for your wall outlets. This is a good investment that is valid for things other than just audio purposes. Rat Shack and any decent hardware store will have them. Cost is under $10.

Try using a "cheater plug" or "ground lifting adapter" on the amp. This takes a three pronged cord and converts it into a two pronged cord.

After these simple and inexpensive "fixes", things get more complex as mentioned above. Like some of the others here, i would rather try to stop the bleeding rather than just band-aid the wound. Find a good dimmer and go from there if that alone does not do the job. Since dimmer's are not "audiophile grade" products, they should be MUCH cheaper than ANY "audiophile" type tweak that would remotely make a dent in fixing the problem. Sean
I had similar thoughts to try the quietline products, as my house has not-so-good wiring. I didn't want to spend 250 bucks on them and local dealers didn't have them for me to try.

I found the music direct has them individually for 27.50 each so, you can try 2 or 3 and see if you like them. (am in no way associated with music direct). shipping is cheap, and fast. Some indiana-based company has them advertised in stereophile for 24.99 each. can't remember the name though.

I thought they improved the picture on my tv a bit. a little less "snow" on cable.

Hope this helps.
You can try a "high" quality dimmer, like the Lutrons that were mentioned. Or check to see that the lighting branch circuit is on the "other" leg of your service. Not the same "leg" as your amp, or branch circuit. If these suggestions to not help, you can buy a rheostat style dimmer. These are used in medical MRI's to dim the lights down with the sensitive equipment. Most require a deep two gang box, and can generate some heat. Good luck!
Khaki8 , I bought my Quiet Line Filters at CES, after I heard the demo,

Sean, I went into a lot of detail about electrical in another post, so won't cover all points. The short version is that I had the electric company do a dedicated transformer, run 220 three phase and install a 750 amp straight thorough box (amp probe meter rather than disconnect type). Then I put all digital on lower leg, all analog on higher leg, and third phase to air conditioning system. The fourteen dedicated breakers are all 10 gauge with a separate TNN ground to true earth. The star ground does not even see the rest of the house.

As far a comments about dimmers, I too have none in my home. The reason I answered the question the way I did was the fact that the poster seemed ready to sell his amp rather than do away with the lighting.

Difficult to know what is important to anyone's family. Add to that, the filters did help my system, even when I had no problem. Looked like an inexpensive option, compared to selling gear. As always, will not fit everyone's needs.
Thanks for filling me in Albert. Sounds like you have an absolutely killer system in every way possible.

I hope i didn't come across as criticizing your suggestions. I've always found your comments and writing style completely enjoyable and well worth paying attention to. While I was simply trying to cover the simplest and least expensive stuff first, I can understand your suggestions also. Like you said though, not everybody thinks or does things the same way. In that respect, it would be better to try some basic filtering before unloading the amp. Sean
Albert, do you have a before and after story on the sound? How much better was it after the "extreme" electric? Does your system always now sound like Sunday morning 3AM.(no I am not kidding). Very late night electric is way way better sounding. I think most of the "gremlins" where folks love their system one day and can't get the "magic" the next day, are all mostly due to electric variations.
Dimmers, even Lutron, are all a nightmare in audio. Halogen track lighing is even worse. The buzzing can even be heard on the lights themselves. Arcmania's post is dead on.
The before and after story is that all the electrical work produced an unmistakable upgrade in performance in every piece in the system. It was obvious from the first few notes, and it got better after some burn in time.

The disappointment comes in the fact that it does not always sound like 3:00 AM Sunday morning. I know what you are describing, and only wish that could be.

The sound is always better than it was before, but still improves during the quiet times you are talking about. A good description would be that the electrical work moved the entire system up, but was unable to overcome the laws of physics (IE: You can still hear the noise, hash and crud on the electrical lines till everyone has finally gone home to bed.)
Albert....not to stray from the thread, but I am interested in your service entrance. Three phase on a home? With "CT" metering? Did you have to pay a fee for the "private" transformer? Do you have to pay a "demand" fee for the three phase? Two seperate grounding electrode systems, not bonded together, no problems with difference of potential? ie, any surges comming in on the grounded conductor (neutral) and passing right by the main ac grounding electrode and out through your equipment to the other grounding system? Just curious......
The CT metering was obtained, only after contacting a supervisor at Texas Utilities. My photo studio is built on the back of my home, and requires 200 amp service. I told them that the house with its normal 200, plus the photo studio's 200 was close enough to go with the big box. They provided at no charge and I paid the electricians to do the install. If someone were to pull my meter, the service would continue without being recorded. Therefore, I have the only meter panel in the neighborhood with a TU keyed padlock installed.

My main reason for wanting this type of box is the fact that the standard version has a huge coil of wire with prongs that plug into your service panel. That way, if the meter is pulled, the service is disconnected. The problem with this is the stereo system is going through that crappy meter and those strange plugs and wires. The panel I have uses solid 8 gauge copper rods to connect the drop to the interior. The meter simply clips around these rods, and reads the usage like an Amprobe would.

All in all, the house has 4 breaker boxes. One is strictly for 220 AC, which branches off with 8 gauge to a sub panel that supplies 220 to my stereo system. I choose Hubbell twist locks and they are floor mounted. All the remaining stereo runs (12 others), are to Hubbell hospital grade with special ground (no strap).

The Photo studio has two panels, one for normal lighting and household outlets, and a heavy duty panel with 10 dedicated runs for photographic lighting and equipment. The remaining panel is a 200 amp Square D which supplies the home, regular stuff like hair dryers and lights.

The requirement for this service was 00 (double zero) drops from the transformer and service. The copper I wanted was available, but required an additional service pole in my back yard to support the additional weight. Calculations by TU said that the run in copper would pull the entire service off the side of my house. I did not want the creosote pole by our swimming pool, so I dropped this idea and went with the standard 00.

The three phase was already in the alley, and the laws concerning utility service in Texas are that the homeowner "must require" the service to obtain it. If it is required, then they must provide the service without penalty. I simply bought a 5 ton Lennox commercial air conditioner for my home, which is 220 three phase, and the drop was free. My electric bill dropped, due to the greater efficiency of the Lennox unit, combined with the greater efficiency of three phase.

The ground issue seems to not be a problem. The household ground is on a 8 gauge run to the copper water supply pipes and then to a big copper rod in the earth provided by the utility. My stereo system is grounded to three copper rods, one under the house, and two outside. They are in a large triangle, and are tied together. My VOM does not show any leakage, and the system is dead quiet.

The first reaction for everyone is that this whole thing is a bit over the top. However, if you consider the investment in stereo gear, the money saved on air conditioning, and the availability of 220 for European goods (should I wish), plus improved meter panel performance, it was a bargain. To put this in perspective, the completed cost was less than the retail price of three Purist Audio Dominus power cords (which I also use). My only regret is not having done it sooner.