Tube Microphone Intermittent Electrical Interference

[Craig F]

you might have a switching power supply (TV, computer, phone, ect.) that is dumping hash on your electrical system or radiating it out

[Torchlight]

Hi Craig! If that is the case what can I do, especially if it is the iMac I am using to run ProTools? Is there a line filter or something like that which I can place on the iMac's AC power line? What do you mean by a switching power supply?

Torchlight

[Craig F]

there are 2 basic types of power supplies, linear and switching
linear: old school, 50% efficient at best, big capacitors, generate some heat
switching: can be 90+% efficient, small, don't generate a lot of heat, are in just about ever consumer product made today (TVs, computers, cell phone chargers, microwaves)


try unplugging everything you can from your house AC power and see if the noise diminishes

if you could post a clip of the noise, someone might identify the source

[Torchlight]

Hi Craig:

Sorry I have not checked back in a few days. I am losing my mind trying to solve this buzzing dilema.

I have an aiff sound file ready to send or post but where can I post it or send it to? Is there a way to attach it in the Forum?

Torchlight

[DigiTechSupt]

Originally Posted by Torchlight

Hi Craig:

Sorry I have not checked back in a few days. I am losing my mind trying to solve this buzzing dilema.

I have an aiff sound file ready to send or post but where can I post it or send it to? Is there a way to attach it in the Forum?

Torchlight

You can use YouSendIt or Whalemail, then post the link in this thread.

[Top Jimmy]

You haven't realized yet that by having the problem in both your home studio setup and your wireless phone, you've pointed to the fact that your problem exists in the electrical distribution system in your house. You may be picking up burst transmission or whatever. Do you live near any broadcasting towers?

I could be wrong, but I'll hazard the guess that you don't live in a modern home with a modern electrical system. Beware the "updates" applied to older electrical systems. I have seen grounded outlets added to ungrounded circuits simply by tying the ground to the neutral at the outlet. Does your ground tie to a rod or plumbing or both? Do you even have a dedicated ground? Look into your electrical situation.

[Torchlight]

Thanks DigiTechSupport for the information on posting a quick sound file. I will try to get that posted soon.

Thanks Top Jimmy for your thoughts on this issue. I actually have a specialist coming to the house Friday morning to investigate the situation and tell me what I need to do. This guy runs a business that is centered around audio design solutions. I spoke with him to set up the appintment and he said that this is exactly what he does for a living. His business is thriving so he must know is stuff. He was recommended to me by an engineer friend of mine.

Someone else mentioned that this could be coming from the power line outside; specifically a failed or damaged isolator. I guess I will wait to see what this guy says on Friday. He has already mentioned possible grounding issues in my 40 year old house. Oh, there is no broadcast antenna anywhere close to where I live in the Maryland suburbs.

Thanks Everyone,

Torchlight

[Craig F]

Originally Posted by Torchlight

Oh, there is no broadcast antenna anywhere close to where I live in the Maryland suburbs.

secret government facility?

[yngvae2]

so it seems as all those dummies are way off. its not a bad tube. i have the same issue with my akg solidtube mic, when i put the mic towards the ceiling it gets super noisy with a loud hum and sounds like its picking up radio stations or something, like its picking up interference from the electrical lines which are where my recessed lights are. but its super quiet on the ground far from the ceiling, i think this is the issue, my c414 is quiet as can be on the ceiling, so maybe it is just the nature of tube mics and i guess they can only exist in pro studios where the ceilings are sky high and shielded better. ill probabaly end up selling this. either that or ill probabaly tape some aluminum foil to the ceiling to block the interference.

so sorry all those guys confused you. its not the tube. i changed 5 tubes and its the same thing each time. the reason its intermittent is because you dont realize youre moving the mic around each time, closer to your electrical wiring. did you ever find a solution? im going to call the mic company tomorrow and see if they know what to do about it.