Buzz from Light Dimmer

[ABDES]

Hi Guys this is my first post so here goes...my problem is a common problem I have a purpose built home studio and like the lights dimmed, problem is when recording guitar, the lights (roatary) dimmer switch x1 causes buzzing its only on guitar this happens all the rest is clean. surely there must be light dimmers out there that eliminate this problem with a filter or choke built in? if anyone knows how to get round this problem please let me know.
Many Thanks

[brandondrury]

I'm not aware of any light dimmers that don't cause noise. They may out there, but I've not heard of them. I'm guessing there may be some kind of stepped version where instead of a continuously variable dimmer, there is simply a number of stepped increments of resistance. I'm merely speculating on that one.

Another option (not quite as eloquent):

I was recording a singer this week who wanted a crazy atmosphere in the studio. The best I could do was turn off the real lights and use only Christmas lights. For $4, I don't think you can beat the "aura" we created.

While you may not want to go that way, I'm sure there are low output lights that could be placed around the room to give you that same mood you are looking for.

Just a thought.

Brandon

[ABDES]

Thanks Brandon, Yeah another friend mentiond a step dimmer rather than a variable one it may work will have to buy one and find out, it's a really common problem I am so meticulous with a quiet studio ie no hiss no hum it's great untill I record guitar then all hell breaks loose so turn the light dimmer off and put a lamp on and all quiet.......Thanks will let you know if it works

[BillyShears]

If I am remembering this correctly (been a number of years) you will not have any more luck with a stepped dimmer.

The problem is caused by the pulses of power going to your light bulb - the shorter the pulses, the less light. When you change the resistor value you are changing the duty cycle (ratio of time when the light is on compared to off) and its these pulses that are causing the noise. So it probably doesn't matter if you step or sweep through these resistor values because the noise happens when the dimmer is "set" at a particular value. I hope I've remembered that correctly.

Brandons xmas light suggestion sounds interesting, I reckon that would be a great solution . Low light , different colours....all of a sudden I want listen to Dark Side Of The Moon.

[brandondrury]

When you change the resistor value you are changing the duty cycle (ratio of time when the light is on compared to off) and its these pulses that are causing the noise.

From a theory standpoint, this is dead on.

I simply assumed these dimmers simply shorted some of the voltage to ground like most circuits work. I didn't realize we were dealing with pulses. I guess this makes sense though.

So it probably doesn't matter if you step or sweep through these resistor values because the noise happens when the dimmer is "set" at a particular value. I hope I've remembered that correctly.

This sounds right. The stepped dimmer won't work then either.

It's time to simply find some softer lights that are independent of your main lighting.

Brandon

[Ethan Winer]

Originally Posted by BillyShears

The problem is caused by the pulses of power going to your light bulb

Exactly. The solution is a variable transformer. More here:

Hum and Buzz

--Ethan

[AndrewClaycomb]

I have electric stepped dimmers in my house (The kind with an LED light and memory), and guitar pickups will still pick up hum. I find it's best to have them up all the way, or off completely.