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Post by cowboycoalminer on Dec 19, 2013 23:37:14 GMT -6
This is a major pain in the ass. I've noticed it before in tracking and never use or allow cell phones in the tracking room. But I just got a new work phone which is a droid and the damn thing outs out so much RF, I thought every piece of tube gear I owned was taking a shit on me. I mean everything in the studio within 10 feet of this thing was picking it up. A word of caution to any that doesn't know about this, turn off the damn phones if you want clean signals.
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Post by jazznoise on Dec 20, 2013 5:06:03 GMT -6
It's a great excuse to have them off, to be honest. Nothing worse than one band member who can't get his face out of his phone..
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Post by svart on Dec 20, 2013 8:55:14 GMT -6
It's not necessarily the RF itself. Unless your tube amp has 2.4Ghz of bandwidth and can downmix something from 700-800mhz or 2.41Ghz.. It's not it.
What it IS, is the pulse trains from the cell radio. The pulses are centered at 700-800mhz or 2.4Ghz but they are roughly 200hz in succession, which means what you hear is the harmonics cause by the transitional edge of the pulses themselves, but not the RF itself.
Anyway, I almost never have issues with cell interference. I used to, but for some reason, I don't anymore.
You might see if you have an ingress point somewhere in your system. Use your phone continuously and walk around seeing where the problem gets worse and try to track it down. Usually you'll find a poor ground, or broken shield or something more, like poor design work on the equipment manufacturer's part.
Generally, even though it seems like a huge issue, cell RF is so low powered that it can't penetrate chassis on equipment and usually sneaks in through fan ports and such.
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Post by cowboycoalminer on Dec 20, 2013 10:07:59 GMT -6
Sta Level is where I hear it most. Open back, tubes in open air. And your right, it is harmonic distortion because if crank the monitors, I can actually hear the harmonics. It also shows up around 200 hertz on a scope like you say. Weird. Everything tube seems more prone to it.
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Post by popmann on Dec 20, 2013 11:10:37 GMT -6
There is a difference in phones. I had a corporate sponsored Blackberry that literally couldn't be on the same FLOOR as the amps. It would barf into it SO loud...iPhone--not an issue. BUT...if I'm fool enough to be right next to the amps (like screwing with the tubes) with it in my pocket, I'll hear a touch of "that sound"...but, nothing like that BB--I think it cause minor heart attacks. Nothing like a cranked tube amp tearing your head off with that cell garbage out of nowhere.
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Post by matt on Dec 20, 2013 14:01:06 GMT -6
Sta Level is where I hear it most. My Sta is noisy too, and in the same way, now that I think about it. Not in a show-stopping fashion, but the thing is most definitely not dead-silent. But I can tweak the levels to minimize the impact, so it remains in the vocal/guitar/bass chain all the time. I will explore this issue tonight. I always have my cell phone near by while at the desk, and it will be interesting to see if it is contributing. |
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Post by svart on Dec 20, 2013 14:26:25 GMT -6
There is a difference in phones. I had a corporate sponsored Blackberry that literally couldn't be on the same FLOOR as the amps. It would barf into it SO loud...iPhone--not an issue. BUT...if I'm fool enough to be right next to the amps (like screwing with the tubes) with it in my pocket, I'll hear a touch of "that sound"...but, nothing like that BB--I think it cause minor heart attacks. Nothing like a cranked tube amp tearing your head off with that cell garbage out of nowhere. Absolutely. The Iphone has one of the lowest power(worst) cell radios used in all cell phones these days. The antenna design is also very poor. Other phones have varying levels of power for their beacons and transmissions. Tubes have no shielding and high gain. Having them out in the open on the back of a box or in an amp with no Faraday cage or anything is asking for ingress. |
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Post by popmann on Dec 20, 2013 14:56:06 GMT -6
Except the BB didn't receive cell calls in the studio...and the iPhone does-same provider. So, "worst" and lowest power isn't the same thing.
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Post by cowboycoalminer on Dec 20, 2013 15:33:23 GMT -6
Sta Level is where I hear it most. My Sta is noisy too, and in the same way, now that I think about it. Not in a show-stopping fashion, but the thing is most definitely not dead-silent. But I can tweak the levels to minimize the impact, so it remains in the vocal/guitar/bass chain all the time. I will explore this issue tonight. I always have my cell phone near by while at the desk, and it will be interesting to see if it is contributing. Matt Mine is dead quite when the phone doesn't come in to play. Yours may need to be adjusted. Use the red button on the back to produce hum (also it helps to be looking at an analyzer on the channel), then tweak the 6v6 adjustment screw until the hum is at it's lowest. That should get the noise floor down below -70. |
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Post by popmann on Dec 20, 2013 17:07:38 GMT -6
Thing has a 6v6 in it? Haysoos...how much makeup gain does it have? A compressor with an external bias adjustment. That is PIMP. You HAVE to get NOS tubes for that baby...
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Post by Martin John Butler on Dec 20, 2013 17:14:37 GMT -6
Dang, I didn't realize the friggin' phone could cause such issues. I've been mixing a little, and hear my iphone ringing in the background on some vocal tracks. These were old tracks, and I shut mine off before sessions now.
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Post by matt on Dec 20, 2013 22:36:29 GMT -6
My Sta is noisy too, and in the same way, now that I think about it. Not in a show-stopping fashion, but the thing is most definitely not dead-silent. But I can tweak the levels to minimize the impact, so it remains in the vocal/guitar/bass chain all the time. I will explore this issue tonight. I always have my cell phone near by while at the desk, and it will be interesting to see if it is contributing. Matt Mine is dead quite when the phone doesn't come in to play. Yours may need to be adjusted. Thanks cowboy! One of the 6V6s was microphonic. I now have a pair of ex-Egnater Rubies in there and no hum. What was previously beautiful is now absolutely gorgeous! |
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Post by Ward on Dec 23, 2013 23:12:17 GMT -6
Turn the damned things off! Or pick a corner with a table in it and put them all over there. We came to work!  |
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Post by keymod on Dec 28, 2013 5:29:01 GMT -6
If I'm working in my office and the computer speakers are turned on, I know a moment or two before when a call or text is coming in because I hear a certain "staticky" noise introduced through the speakers. I then glance over at my phone ( usually sitting on a table a few feet away ) and, sure enough, I watch it light up and ring. This slight delay is an interesting phenomenon to me.
I have recently been searching for a new property to buy a house. Found a great deal on several acres with an old Victorian home and a very large barn. I thought great! I can build the studio in the barn and then fix up the house a little at a time. Then I found out that there is an easement lease on the property for a very large cell phone tower. Turned me off to the whole deal.
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Post by mobeach on Dec 28, 2013 7:00:39 GMT -6
There's a good reason they're not allowed in medical buildings as they can mess with some equipment.
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