[cloudbaseracer]

Hello Guys,

Please let me know if there is a better, more correct circle for this post.

Here is my scenario....

I have moved into my new house and I am experiencing an issue with the 2 channel stereo system "cutting/dropping out" when I turn on certain lights.  Essentially when the switch is thrown there is a brief (1/10th of a second) silence in the music.  Sometimes the systems actually "muffles" the sound and it seems super constricted.  Neither the dropping out or the muffling occur at every single throw of the light switch but it is easy to get it to do it.

Here are the further details.  The amps that I am using are the Panasonic XR-700 running in the digital mode and being played through Emerald Physics CS2's.  I have 2 dedicated Hubble 20 amp outlets that are dedicated specifically for two channel and run directly back to the panel.   The lights that are causing the problems are a cable light system from Tech Lighting.  This system uses a magnetic transformer to energize an actual cable that the lights are "screwed" into.  By that, I mean that there are actual screws that pierce the plastic sheath to allow the energy to flow into the light fixture.  Very cool system but may be the cause of my issue.

An update-- I just tested with the TV/Cable loudly playing through the Panasonic/CS2 system but it did not seem to do the same dropping out. 

Is there a reason that they cable system should interfere with the CD player but not the TV?

This is all very strange to me.  Makes no sense at all.


Please help,

James

[tekwiz]

.

[richidoo]

My guess is that the CD player is more sensitive to the voltage dip caused by the track light transformer charging up than the cable box. The fact that the CDP and light are on different circuits is the part that ruins my theory. But if the circuit that the light transformer is on has high resistance connection(s), like a sloppy wire nut, it would draw a lot of current which could affect other circuits at least on the same leg of the panel. My refrigerator makes my tube amps bias reading dip by 5% then it recovers as the motor gets up to speed, but they are on different circuits. High resistance connections are common in modern residential construction with non-career electrician helpers. You need to open up each junction box between the light and the panel to make sure all the connections are nice and strong. You can redo them yourself if necessary if you shut off the breaker.

While you're at it, you mentioned you have a new home, get an outlet tester and check every outlet in the house. The electrician will fix it for free if you find errors.

You could also experiment with an extension cord, plug the CDP into an outlet connected to a breaker on the other side of the service panel. It will use the other hot leg from the street and be unaffected by the loads on the other leg. Both your dedicated lines should be on the same leg, btw. Or plug the light into another circuit if possible.  If it still happens then I don't know what to try. 

edit: I like Jeff's idea, an inductor stores current in magnetic field so smooth out spikes. If you have a UPS try it on the CDP to confirm it is power spike the prob.

[cloudbaseracer]

Thanks for the input.

What would explain that the music is actually "muffled" while it continues to play?  This does not happen all the time but it does happen frequently enough to notice.  It is correct that the noise only occurs when the lights are switched on and not when they are turned off.  It is also notable that it does not happen at every flip of the switch?   My testing of this has been essentially rapidly turning the lights on and off.  There are 3 of these  cable lights installed - (2) that are about 41' and a single that is 25' long. 

Why do you say that the dedicated outlets need to be on the same leg?  I think they may be split up but have to confirm - as typical with electricians, they are not labeled clearly.

I probably had it wired using Aluminum but will need to confirm.

The Tech Lighting transformers are 300 watt units and actually caused a different problem initially.  I have tried to do my whole house super energy efficient and thus installed LED bulbs at 8 watts each.  For the 40' run there were 10 bulbs for a total of 80 watts.  This caused a low noise "hum" from the transformer itself.  When I noticed this I was totally dejected because the bulbs themselves are $40 each and I had purchased 29 of them!! It turns out that I did not have enough of a wattage draw to eliminate the hum.  I had to replace one of the 8watt LED bulbs with a 50 Watt halogen to get the total draw up.  Not what I had originally wanted but it solved that issue.  Needless to say it is frustrating when you invest around 5 grand for a "few" lights and they give you fits.

And now i have this issue which seems to be related to these cable lights as well!!  Live and learn I guess. 

Also, I have a wireless plug that I can activate through a piezoelectric switch.  The unit is called a "Lightning Switch" and works through mechanical/physical action.  It does not even use batteries in the "remote". By depressing the button a signal is sent to the receiver which is actually plugged in to an outlet in my floor.  I use this to turn a lamp on and off and it is a really neat piece of hardware.  Why do I mention all of this?  Because I have noticed that the lamp will not turn on or off (receiver activate) when the cable light that is close to it is actually on.  I have to get within 4-5 feet of the lamp before the signal from the remote will activate the receiver.  As soon as I turn the cable light off the Lightning Switch will work again from a normal 40 or so feet.  It is obvious that there is some type of EMF being produced and I don't think it is a good thing!

I know this is not a lighting forum but I just wanted to give you all the facts as I currently know them to be.  Any new thoughts?

Thanks,

James

[srb]

Most low-voltage lighting systems offer both electronic and magnetic transformers.  The magnetic transformers operate at 50/60Hz, are larger and heavier than the electronic type, and less efficient.  However, they normally don't generate interference.
 
The electronic transformers operate at higher frequencies and often generate interference in electronics and audio circuits.  They usually need a load of 50% or more of the rated output, which made me think that you have the electronic type.
 
But then I re-read your initial post and realized you said you have the magnetic type.  Hmm...are these dimmable LEDs that you have hooked up with a dimmer?
 
Steve

[Wayner]

First, lets get some things straight. A 300VA stepdown transformer is a pretty big transformer (I'll assume it's secondary is 12 volt?) and magnetic transformers generate a magnetic field, continuously. Magnetic transformers should not be loaded more the 65% of their VA rating.

A 300VA solidstate power supply would be a rather spendy item. Solid state power supplies are used in very high tech machines everyday and are usually highly shielded so I dout they are the source of noise.

Now, the transformed 12 volts is still AC. So how did the LEDs voltage get changed from AC to DC 'cause LEDs don't like AC, or is your transformer really a power supply and has a rectifier in it to make DC?

Wayner

[richidoo]

The two legs of 220 coming into the house are on different phase. You want to use the same phase throughout the audio system.  If the two legs are not on same phase it is easy to swap two adjacent breakers to correct it. If you are not comfortable with LIVE 220 volt electricity don't do this yourself.  If it sounds fine now, don't worry about it.
http://electrical.about.com/od/panelsdistribution/a/breakerpanels.htm

How long does the muffled sound last? In the first post you suggested the muffle and the drop out last 1/10 of a second. If muffled sound lasts longer, it  could be something else, defect with the CDP or EMI to do with the lights, RF from digital amps, etc. Can you try an uninterruptible power supply on the CDP to see if that corrects the problem. Is the lighting transformer enclosed in a steel box?

[Speedskater]

a) Most modern interior AC power wiring is done in copper.  Your local power company does use aluminum wire,  but it takes special tools and connectors.  Nothing wrong with aluminum wire, but all it's special rules must be followed. Those special aluminum rules make it dangerous to use inside a house, because sooner or later someone will break a rule.

b) If I was going to wire a listening room that had high power amplifiers, I would use both 120V phases, and a shared neutral wire (I know everyone thinks that shared neutrals are bad) to as close to the amps as possible. This will reduce the line voltage drop, reduce the neutral voltage drop and keep the neutral voltage closer to the safety ground voltage.

c) The problem maybe that the digital interconnects are picking up noise pulses, try using heavily shielded plan-jane interconnects.

[richidoo]

Blue Jeans Cable has such a shielded cable, made with Beldon 1505 coax cable. Extremely good performance and build quality for the price.

[Wayner]

I guess I'm more concerned about the lighting project then the noise caused by it. I went to the Tech Lighting website and couldn't find the products you are describing. They don't have any "rope light" and the largest VA transformer was 100VA.

I'm just hoping the system is installed correctly and that components, wire gauge size and other things have been considered as this sounds like a DIY project of sorts or isn't it?

Also, this is a very disturbing trend that I have come across more then once where someone is trying to be "energy efficient" and end up spending thousands of dollars on a system that barely works or causes other problems. Do you know how long you could have operated a conventional lighting system for the money you've already spent?

There is also several factors that no one considers. First, the transformer if on is consuming some level of current, even if there is only one light on the system. There is a base power requirement cost for the transformer to be plugged in.

Secondly, there are at least 3 lighting schemes that need to be considered and blended if you are going to do a good lighting job. First is what I call "mood" lighting. This can be a very soft lighting, not requiring much power and good old incandescents on dimmers in an indirect fashion can accomplish this very well. The second level of lighting is called "task" lighting. This is usually confined to a small space or zone in which someone wishes to read or do a small craft, where lots of light is required in a small space. The third kind of lighting is called "twinkle" and is another effect type of lighting. This is where low level, low voltage stuff can come into play. It just addes a little fun to the room and costs very little to operate. The 4th level is simply called "the work lights". This is when everyting is put on full blast to do cleaning, maintenance and other high visability taskes require goobs of light.

In my HT room, I have 4 indirect wall sconces mounted about 2 feet from the ceiling. I have a 40 watt a19 bulb mounted in them. I can dim them to such a low level that it just looks like fire coming out of the fixtures, to dimmer, full open to then become the work lights. Amazing how much light can come out when it's properly designed. The wife likes to do cross-point at night when we either watch TV or listen to music and I have a small column mounted task light for her. It doesn't distract from the rooms mood lighting, and she can see what she is doing.

Wayner

[Wayner]

I want to add this about modern day dimmers. They are not the old day rheostats used to suck up power. They have a solid state device in them called a triac that is a very fast switch. It is designed with the level control to allow adjustable portions of the half cycle to go to the lamp. As an example, a 40 watt lamp on a dimmer set at half will equate to a 26 watt lamp and increase lamp life up to 35 times!!!! I've had my 40 watts in my HT room for 16 years without failure.

While a dimmer control may not be suitable for every room, it certainly has it's place for setting the mood and saving energy. If you think the 26 watt PL lamps have as much lumens as a 100 watt incandescent, go flip flop them in the laundry room with the wife present. She will want the 100 watt incandescent instantly.

Wayner

[twitch54]

If you think the 26 watt PL lamps have as much lumens as a 100 watt incandescent, go flip flop them in the laundry room with the wife present. She will want the 100 watt incandescent instantly.

Boy is that the truth !!  Wayner, I'm curious with respect to the current dimmer devices.....are the 'noise' issues the same ?? or was more a function of the old rheostat ?

[Wayner]

I have had some dimmers that will make the filaments sing. I like the Leviton brand the best. That is an audiable noise. I haven't heard any electrical as most high quality dimmers have filters to keep the line clean.

Of course, always make sure the lamp you are dimming is not routed from a wall outlet as dimmers will screw up stereo systems, motors and stuff like that. Almost all electricans will keep the lighting seperate from outlets, but you always need to check.

I didn't mean to turn this thread sideways, but the topic has a bit of duality.

Wayner

[cloudbaseracer]

Wayne,

I am using Kable Lights - not track nor rope.

http://www.techlighting.com/default.asp?page=products&subpage=systembasics&sysid=3&cls=97&nme=Basics&systype=KL

The Tech Transformer:
http://www.brilliantlighting.com/cart/transformers_18.htm

The heads (not that it matters) are - http://www.techlighting.com/default.asp?page=products&subpage=systemfixdet&fixid=116&sysid=3&cls=1&nme=Heads&systype=KL

My dimmers are Copper Aspire Slide Dimmer - http://www.acehardwaresuperstore.com/aspire-slide-dimmer-600w-incandescent-p-81243.html?ref=42

[srb]

I see that the Cooper Aspire dimmers have two modes - instant on and gradual on.  Have you tried both modes?
 
Also, as a test you could temporarily try a regular on/off switch just to take the dimmer switch out of the equation.
 
Steve

[Wayner]

Thanks for the info, cloudbaseracer! Now I get the whole picture. So to sum up the lighting system (and these are way cool), you have a 300 watt 12 volt AC transformer then going thru the dimmer control and then to the lighting cables. Everything seems normal.

I do suspect an interaction between the dimmer control and the transformer. I am curious if the noise happens (when you turn the lights on) when the dimmer is full open (no dimming). If you could do that and report back, that would be helpful.

Wayner

[Wayner]

I may have just had a dumb ass moment. The dimmer has to be before the transformer 'cause the triac in the dimmer control runs on 120 volt. So the dimmer drops the half cycle time to the transformer, which ends up going to the lights on the secondary. Is that the way it's wired?

Wayner

[Wayner]

Here is an interesting blurb out of my Leviton reference book: Power switching circuits, such as those, which operate dimmers, are capable of generating electrical noise. Instead of a smooth rise in power, the current goes instantaneously from zero to whatever the load current level is at the moment the triac is triggered on. This is called a current step and it occurs every half cycle. The current step creates an electromagnetic field. While the fundemental frequency of the AC line current is 60hz, it's harmonics extends well past the AM radio frequency band, creating radio frequency interference (RFI).

The RFI can be radiated or conducted directly from the dimmer through the AC power lines. AM radios are the most susceptible to this noise, but sensitive audio equipment, microphone cables, PA systems and intercoms may also be affected.

Some common sense precautions can prevent difficulties for the noise-sensitive equipment. Do not place sensitive equipment directly near dimmer installations. Make sure microphone and audio cables do not run parallel to the dimmer wiring. Low impedance audio cables offer further protection (Bluesjeans cables) as does proper grounding of the audio system.

That's it right out of their book.

Wayner

[cloudbaseracer]

Thanks for all your replies and effort.  I got tied up on something else but very much appreciate your help.  Keep any info coming you may have.


I have tried the system with a standard switch-replacing the dimmer but this was only an effort to remove the preliminary hum.  I have not inserted one since I was able to remove the hum via the addition of a 50watt MR16 halogen bulb.  Not sure if it would make a difference or not.

I have tried turning the lights on with the dimmers turned down to a level where they are just barely on.  This does not mean that the slider on the dimmer is all the way at the bottom.  It simply means that this is the level prior to the lights cutting out- any lower and they flicker.  I estimate it to be around 25%.  Did not even measure it- just from memory.  The arching/popping noise still present. 

The dimmer is wired before the transformer as far as I know.


Thanks,

James