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Apartment Studio ... Bad Power?
Old 21st January 2007
  #1
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norman_nomad's Avatar
Apartment Studio ... Bad Power?

Hey Geekslutz,

I have a peculiar problem. I have an audio mixing room in my apartment. I have all of the gear hooked up to one outlet, which includes my computer, converters and about 12 pieces of outboard gear.

My problem: For whatever reason, my audio will just completely cut out in the middle of playback. Right before the audio cuts out, I hear this very strange envelope filter type of sound. The sound is pretty loud ... and it sounds bad. It's hard to explain, but it sounds almost exactly like the light saber sound effect in the movie Star Wars.

My computer and outboard stay on, but all of the audio cuts out.

Anyhow, I've never come up against this before... does this sound familiar? Is it possible I'm trying to draw too much current from the one outlet? (my problem seems to be worse late at night and I'm guessing city drops power to the grid sometime after 2am).

What are some test I can perform in order to help remedy my problem?

Thanks for any help you might be able to provide!
Old 21st January 2007
  #2
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Hi
There are many possibilities here!
I doubt ALL the gear is 'dropping out' so find out which one is the culprit.
Use a multimeter (carefully) and monitor the mains and see if it does actually dip and by how much.
Does all your gear work OK in another location?
Is the dip momentary or prolonged?
If it really does dip, consider a UPS or AVR supply.
More info needed!!
Matt S
Old 21st January 2007
  #3
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norman_nomad's Avatar
Hey Matt,

Thanks for the response.

When that "light saber" noise happens, all audio cuts out and I'm left, instead, with a constant low frequency hum. The hum stays on indefinitely until I cut power from the *entire* system for a few seconds.

When I reboot everything, the hum is gone and I'm back to normal.

All of my gear worked fine in another location in the *same apartment* actually.

When testing my wall socket with a multimeter, I'm guessing I should set it for AC, apply the black lead to the 3rd ground pin and the red lead to one of the other two to check for 120v?

Damon
Old 21st January 2007
  #4
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hi
So if you have lights on (ceiling or desk lamps) do they go dim momentarily or stay dim?
If it is only momentarily then one of your pieces of kit is faulty as it seems to need 'resetting' by putting the power off then back on again. You should try turning only your monitor amp off and see if the hum clears,. If no difference, try the mixer.
Please wait for an American contributor to advise on testing your power as I can't remember your details but basically red of meter to one supply then black to the other and you need the meter set to AC.
Matt S
Old 22nd January 2007
  #5
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norman_nomad's Avatar
Thanks again Matt for the reply.

There is no light dimming or any other outside symptoms other than that audio cuts out and I'm left with just a constant humming noise until I power down all of my gear....


Anyone else know what this might be?
Old 22nd January 2007
  #6
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Wavebourn's Avatar
 

Hmmm.... May be it happens when you patch somehow output to input?
Old 22nd January 2007
  #7
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norman_nomad's Avatar
Quote:
Originally Posted by moracspace View Post
I highly doubt its the electrical outlet.I think in your outboard gear.Do you have a patchbay?To test an outlet take both test leads to the slotted parts of the outlet not to the ground.You will only read half the voltage to ground
Hey Moracspace.... the more I think about it... the more I think you're right. I do have a patchbay... it's one of the CM labs digitally controlled patchbays... at first I thought this might be the culpret... so I turned it off... then back on, and the hum was still there.

I think I'll try to go through each piece of outboard gear systematically next time this happens and see if powering down one of them makes a difference.

I'll measure the outlet with my multi-meter. What voltage range should I be looking for? How low is "too low" ?

Quote:
Originally Posted by Wavebourn
Hmmm.... May be it happens when you patch somehow output to input?
No... it happens despite patch settings. I haven't changed my patch settings in awhile now. The only pattern I've seen, is that it occurs more frequently at night, and I think it may relate to how stressed my computer system is (last night it was happening repeatedly as I was working through a dense mix session with many plug-ins).
Old 22nd January 2007
  #8
I get this sound sometimes when my computer is overloaded and can't handle all the plugs and tracks. What software, computer, how much RAM, etc?

Edwin
Old 22nd January 2007
  #9
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norman_nomad's Avatar
Nuendo, AMD 3800 Dual core, 2 Gigs of ram. It's a good computer; I've had it running fine for over a year and it hasn't given me any troubles. This is the first problem I've had in my new room.


I just measured my wall socket and I'm reading 122v. I'll measure late tonight as well.
Old 22nd January 2007
  #10
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Quote:
Originally Posted by moracspace View Post
I highly doubt its the electrical outlet.I think in your outboard gear.Do you have a patchbay?To test an outlet take both test leads to the slotted parts of the outlet not to the ground.You will only read half the voltage to ground
That's true in Europe, Asia, and many parts of the world, but not San Francisco. The USA has 120 volt power, with one side ("neutral") of the receptacle connected to ground at the power panel.

So, normally you will see 120 volts between the smaller blade ("hot") and the larger blade ("neutral"). You will see the same between hot and ground, and zero volts between neutral and ground.

I'd guess that your problem is in a piece of gear. It might be an AC strip of something, but that's less likely. Try working with a few pieces turned off and see what happens. Maybe you can rotate this test among various pieces in your system and narrow it down that way.

You could plug a small lamp into the power strip that feeds your gear. Leave it on and see whether it dims when the problem occurs.
Old 22nd January 2007
  #11
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Kayo's Avatar
 

Apart from the sound issue////

And, It's been argued, many a times before, and i'll even vouch for it here.

A filtered power supply, (which can be attained via a UPS or power filtering), has tremendous benifits to the audio setup. No matter where you are!

Try it,.... things may change for the better.
Old 22nd January 2007
  #12
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norman_nomad's Avatar
Thanks for the explanation David... I did some reading online before sticking my multimeter leads into the socket and it seems to say that neutral is usually tied to ground (as you stated)... which left me confused as to why I couldn't measure between hot and ground... but it makes sense that it's different for different countries...

I'll try the lamp trick. Admittedly I have the very cheapest power strips (Radioshack) and plan on upgrading to something better. So that may be the problem.

FaTT Dust -

I've considered a UPS and have done numerous searches here on GS, but there seems to be so much conflicting information that I'm not sure if I need one/could benefit from one. It seems that unless I get an expensive one that is continuous on and generates a true sinewave output I might end up feeding my gear square wave AC which would be worse that whats coming out of the socket... although I guess I'd be OK if the power went out.

Why do you suggest the UPS?
Old 22nd January 2007
  #13
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norman_nomad's Avatar
Update:

It's the patchbay! Thanks guys for making me double check everything!

The hum happened again around 1:30am. This time I turned off my patchbay, but left it off for a good 30 seconds. This was enough to "reset" the hum and put everything back to normal.

I measured the outlet and I was at 124v. So I don't think power sagging is my immediate problem.

So, question: Why might this be happening primarily at night? (I know this is probably a hard/impossible question to answer).

Is it still worth investing in a UPS, or even balanced power solution?
Old 22nd January 2007
  #14
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theres no way i would trust my $100's or $1000's (now) worth of equipment to regular line power... i filter and UPS power to ALL of my equipment.... theres a good chance your digi-patchbay was harmed by dips,spikes, or surges....

i have an APC 350 UPS... andthat has its power pre-filtered... its not top of the line.. but it gives me pretty consistent and clean power...

make sure to do some research first.. many filters are just a cap across the wires
(rack rider makes a bunch of overpriced crap like that).... other are more advanced filters and regulators..
i;ve seen some threads before (not here i dont think) where people took pics of the insides of their filters to compare and it was a great difference (and not necessarily price related)

gl
Old 22nd January 2007
  #15
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Wavebourn's Avatar
 

So, it is your patchbay that creates feedback patching something from output to input... Sorry, I thought it was you...
Old 22nd January 2007
  #16
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Hi
Sounds more like a power supply regulator in the unit perhaps overheating and shutting down or a peculiar 'switchmode' supply fault if it is that type.
Matt S
Old 22nd January 2007
  #17
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Wavebourn's Avatar
 

Quote:
Originally Posted by Matt Syson View Post
Hi
Sounds more like a power supply regulator in the unit perhaps overheating and shutting down or a peculiar 'switchmode' supply fault if it is that type.
Matt S
May be.
Old 23rd January 2007
  #18
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norman_nomad's Avatar
Quote:
Originally Posted by Disjointed View Post
i have an APC 350 UPS... andthat has its power pre-filtered... its not top of the line.. but it gives me pretty consistent and clean power...


gl
So that $50 APC 350 will better than feeding my gear what's coming through the wall?

Will this really clean up my power more than what the power supplies in my gear are already doing?

Why is this better than, say, a standard surge protector power strip (save the switching feature in the event of a blackout)?
Old 24th January 2007
  #19
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Sensater's Avatar
 

A lot of people will say that plugging an amp into a UPS is a bad idea....that the UPS will restrict the transients of the amp.......and the thinking is also that any well-designed power amp will also have a beefy/good unough power supply to deal with a lot of power anomalies, short of a loss of power, of course. Me, I'm in an apartment too, and I plug my Hafler amp directly into one socket, and a Monster power strip into the other handles all of my outboard, converters, etc. The computers are on a UPS. I've never had a problem with this setup. Make sure your electrical ground is a good one....

Good luck!
-Steve



Quote:
Originally Posted by norman_nomad View Post
So that $50 APC 350 will better than feeding my gear what's coming through the wall?

Will this really clean up my power more than what the power supplies in my gear are already doing?

Why is this better than, say, a standard surge protector power strip (save the switching feature in the event of a blackout)?
Old 24th January 2007
  #20
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Disjointed's Avatar
 

my location suffers from frequent drops and occasional power loss.... the UPS is a necessity in my location (including computers, A/D/A's, etc...)

there have been many times when i have noticed the UPS activating during drops and surges (the little light changes)...

if your power is relatively consistent.. maybe.. its not a necessity.. and the money might be better well spent on a good conditioner...

the radio shack power strips.. probably just have a cap across the wires to limit RF and other unwanted freq to your equipment...



gl
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