# Do not use cheap light dimmer switches from amazon...



## chillbot (Mar 22, 2017)

...probably goes without saying.

...unless your idea of fun is spending an afternoon chasing down a buzz in your studio, trying every possibility of ground lifts and plugging things into all different outlets and surge protectors only to finally luck into finding it's a sole dimmer switch plugged into a wall outlet across the room that nothing else is plugged into.


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## Silence-is-Golden (Mar 23, 2017)

Yeah, buzzes can make one go crazy if not found but undeniably present.

Morale of your story: Don't take light lightly!

Or: seperate your studio environment's electrical circuit from all other at your source connection in da house.


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## GdT (Mar 23, 2017)

I had something similar. The guys who put my room together used a cheapo light dimmer switch to control the speed of the fresh air input duct fan. And the wiring was so tight it was a big struggle to replace it with a proper purpose designed controller switch.
You just have watch out what they dish up!


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## synthpunk (Mar 23, 2017)

Very good advice if you can try and put your equipment on its own breakers separate from lighting and miscellaneous. I have separate lines for audio and I.T.



Silence-is-Golden said:


> Yeah, buzzes can make one go crazy if not found but undeniably present.
> 
> Morale of your story: Don't take light lightly!
> 
> Or: seperate your studio environment's electrical circuit from all other at your source connection in da house.


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## Smikes77 (Mar 23, 2017)

Not a light switch, but something equally annoying...

An old guitar teaching of mine kept getting an electric shock everytime he bent under the studio desk to change some cables, and couldn`t figure out for the life of him why. This happened all day. He swears he wasn`t touching anything when it happened.

When he put a light underneath the desk, he could see the top string of a guitar jammed into the wall socket. So thin he couldn`t see it initally.


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## chillbot (Mar 26, 2017)

Smikes77 said:


> An old guitar teaching of mine kept getting an electric shock everytime he bent under the studio desk to change some cables, and couldn`t figure out for the life of him why. This happened all day. He swears he wasn`t touching anything when it happened.
> 
> When he put a light underneath the desk, he could see the top string of a guitar jammed into the wall socket. So thin he couldn`t see it initally.


Crazy.

So... my Fender Rhodes is still getting a buzz from.... sitting next to a digital mixer. At the time when I was trouble-shooting the buzz I had the mixer pulled out a bit to access the cables behind it (it's on a wheeled rack). When I push it back into place next to the Rhodes, the Rhodes picks up a buzz. Is this normal? Anyone know anything about this? It's not even close to as bad as the buzz from the amazon dimmer... in fact it's probably recordable as-is. I have to turn the Rhodes up pretty loud, BUT... as soon as I pull the rack out a foot or so the buzz goes away....


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## synthpunk (Mar 26, 2017)

The pickups inside Rhoads can be very sensitive as you probably know. My guess would be your mixer is omitting some sort of digital noise that the rhoads pickups are picking up. This can also happen for example when you place a laptop on top of the rhoads body. The easiest solution would be to find some sort of alternate arrangement. You could also look into having your Tech Shield the preamp section of the rhoads better but there is no guarantee.


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## Nick Batzdorf (Mar 26, 2017)

That's airborne noise. The first thing is to try re-routing cables.


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## Nick Batzdorf (Mar 26, 2017)

Or what synthpunk says. I haven't owned a Rhodes since 1985, so wadda I know.


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## chillbot (Mar 26, 2017)

Nick Batzdorf said:


> That's airborne noise. The first thing is to try re-routing cables.


Not much can be done about rerouting cables without remodeling the entire room. However... it's not all that bad. I have to turn the rhodes up to about 6-7 to even begin to hear the buzz, which, if you rhodes you know that's pretty damn loud. Almost all of the time I'm recording below those levels and I have a gate on the channel that I've got set for good action. If I'm recording something softer and want to turn it up I just have to pull the mixer rack out a couple feet I guess. It's not really a problem I'm just a perfectionist and a buzz is a buzz....


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## synthpunk (Mar 26, 2017)

Are you using balanced audio cables?


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## Nick Batzdorf (Mar 27, 2017)

How about ferrite beads?


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## wst3 (Mar 27, 2017)

how about chicken bones and...

The preamp in a Rhodes is not the epitome of current thinking on EMI/RFI protection, why would it be? But it is the pickups that are usually the real source of the problem! In fact, I think the output of the Rhodes presents a fairly high source impedance, high with respect to modern designs anyway, so that's even suspect. And it is single ended unless you've modified your piano...

First things first - what does the noise sound like? Is it a 60 cycle hum, broadband noise, digital hash, the AM station... we need to know where in the spectrum the noise falls. This allows us to identify the aggressor, the source of the noise.

Next we need to decide whether we want to treat the victim (the Rhodes pickups most likely, but it could be cables, the preamp, etc), or the aggressor (which could also be several differen things.)

But we need to do this one step at a time, so please let us know what the noise sounds like.

If you are curious...


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## chillbot (Mar 27, 2017)

It's most definitely 60Hz hum. When I had the cheap amazon dimmer switch plugged in I it was much louder and I could hear it in both the Rhodes and the Leslie. (Incidentally, I replaced the cheap amazon dimmer switch with an expensive amazon dimmer switch and it got rid of the noise, go figure.) It seems like bringing the power source of the digital mixer (I'm guessing) within a foot or two of the Rhodes starts it humming. Move it away, it's quiet. As I mentioned though, it's not really noticeable at the levels I play/record so I'm not too worried. If I ever need to I can just roll the mixer out.


synthpunk said:


> Are you using balanced audio cables?


Yes, 6 for 3 synths, also 5 mic cables, that's it for going into the mixer, besides a few power cords here and there.


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## Joe_D (Mar 27, 2017)

As far as cheap troubleshooting goes, did you try a good quality short (say 1 foot or 0,3 meter) patch cord going into a good (preferably active) direct box, and then XLR into a mic preamp (I'm assuming that you have the typical Rhodes passive pickup, not a Dyno mod or similar)?


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## Nick Batzdorf (Mar 27, 2017)

Bill, cbot posted that the hum disappears when he moves the keyboard away from his mixer's power supply. It's definitely induced 60Hz hum.

Thinking about it, ferrite beads are good for RF, not hum, so that was one of my rare bad ideas. But it sounds to me like a shielding issue, however you slice it.


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## Nick Batzdorf (Mar 27, 2017)

The dimmer was an additional hum source, by the way.


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## synthpunk (Mar 27, 2017)

Kids these days go to great lengths to add hums, noises, hiss to their music

Seriously though, did you say that your mixer has a separate psu or is it built in ?


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## wst3 (Mar 27, 2017)

Shielding has almost no effect at 60 Hz, distance helps (falls off by inverse square law), twisted pairs are very effective IF you have a properly balanced (high common mode rejection ratio) input. There are other tricks as well, my go-to is converting a single-ended output to impedance balanced (which is redundant!).

And yeah, it seemed likely that it was power line induced, but I don't like to make assumptions blindly.


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## ceemusic (Mar 27, 2017)

I picked up the Furman PL-Plus DMC about 10 years ago. This took care of my noise problems plus the voltmeter/ammeter helps me keep tabs on low voltage during the hot summer months here in the N.E..


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## chillbot (Mar 27, 2017)

Nick Batzdorf said:


> that was one of my rare bad ideas


So modest!


synthpunk said:


> did you say that your mixer has a separate psu or is it built in


Internal.


ceemusic said:


> I picked up the Furman PL-Plus


I have 6 of these in the studio, they are great.


Joe_D said:


> As far as cheap troubleshooting goes, did you try a good quality short (say 1 foot or 0,3 meter) patch cord going into a good (preferably active) direct box, and then XLR into a mic preamp (I'm assuming that you have the typical Rhodes passive pickup, not a Dyno mod or similar)?


To be clear, the buzz is in the Rhodes itself in the speakers. It's also present in the direct outs and the headphone out but it's not cable-induced. And it's not just this specific mixer which happens to sit by it that causes the buzz, it seems to be pretty much any powered electronics that come in close proximity to it. Is this normal in a Rhodes? Fortunately, and perhaps oddly, the Arturia Matrixbrute sitting on top of the Rhodes does not cause any buzzing, even with an internal power supply. But the Matrixbrute has a very heavy case and probably a lot of shielding with that case. Maybe I should experiment with shielding the inside of the rack where the mixer is?


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## Joe_D (Mar 27, 2017)

Sorry; I missed that it's a suitcase.


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## chillbot (Mar 27, 2017)

Joe_D said:


> Sorry; I missed that it's a suitcase.


I probably never mentioned it...


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## wst3 (Mar 27, 2017)

chillbot said:


> To be clear, the buzz is in the Rhodes itself in the speakers. It's also present in the direct outs and the headphone out but it's not cable-induced. And it's not just this specific mixer which happens to sit by it that causes the buzz, it seems to be pretty much any powered electronics that come in close proximity to it. Is this normal in a Rhodes?


Normal is highly overrated<G>... this is normal in any electronic device with a single-ended, high impedance input (Strat, Rhodes, etc). You've done an excellent job trouble-shooting - you've narrowed the list of victims to the pickup assembly in the Rhodes or possibly the preamp, and the aggressor is some nearby source of 60 Hz radiation. 



chillbot said:


> Fortunately, and perhaps oddly, the Arturia Matrixbrute sitting on top of the Rhodes does not cause any buzzing, even with an internal power supply. But the Matrixbrute has a very heavy case and probably a lot of shielding with that case. Maybe I should experiment with shielding the inside of the rack where the mixer is?


At the risk of repeating myself, shielding does nothing to reduce 60 Hz noises - at 60 Hz the wavelength is almost 19 feet - a shield is going to present little impediment.

Best guess - the Arturia has a switching power supply, and operates at a very high frequency, one that is blocked by shielding if it can even travel that far. Curious, did you mention the make and model of the mixer? If it is old enough it may have a linear power supply, one that operates at line frequency, and that could be the aggressor. Could be...

I also would not focus on the rack, or even the mixer, you say many electronic devices can cause a problem when they are close by. Lots of aggressors, only one victim, focus on the victim.

One solution that is nearly guaranteed to work (if we've got our facts straight) is an active preamp in the Rhodes. Problem is, that will affect the tone, and you might not like it...


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