Grounding a CRT monitor

Don't see a specific place for your hardware question? This is the forum for you!

Moderators: mac_h8r1, Nemesis

Re: Grounding a CRT monitor

Postposted on Mon Mar 24, 2014 6:33 am

The Egg wrote:Well.....definitely not the ground then. You might try a couple cheap ferrites for the mic cable as a last resort.

Yeah, that seems like a rather long shot to me. Ferrites aren't going to do anything for low frequency interference like hum.

Meadows wrote:The audio enthusiast friend I mentioned (as in for real, not like how audiophiles are) promised to build me a few cheap microphones from parts and endow them with fancy shielded cables and the works, so first of all we'll test that before investing in anything serious.

That's certainly worth a try. Given any thought to the USB headset idea?

Meadows wrote:Also, an electrician will look at the place tomorrow.

Can't hurt. And if you've got a wiring problem you definitely want to find out and have it dealt with since it can be a safety hazard.
(this space intentionally left blank)
just brew it!
Administrator
Gold subscriber
 
 
Posts: 37637
Joined: Tue Aug 20, 2002 10:51 pm
Location: Somewhere, having a beer

Re: Grounding a CRT monitor

Postposted on Mon Mar 24, 2014 4:31 pm

just brew it! wrote:Given any thought to the USB headset idea?

Yes, but I'm not going to spend more money on the problem than I need to. Currently waiting to pick up the newly built microphones.
Meadows
Grand Gerbil Poohbah
Silver subscriber
 
 
Posts: 3152
Joined: Mon Oct 08, 2007 1:10 pm
Location: Location: Location

Re: Grounding a CRT monitor

Postposted on Wed Mar 26, 2014 6:34 pm

Meadows I will give you this: you are uncompromising. Such men are hard to find, kudos to you.
dashbarron
Gerbil Team Leader
Gold subscriber
 
 
Posts: 205
Joined: Tue Aug 11, 2009 8:49 am

Re: Grounding a CRT monitor

Postposted on Wed Mar 26, 2014 6:49 pm

dashbarron wrote:Meadows I will give you this: you are uncompromising. Such men are hard to find, kudos to you.

Uh... thanks? :P
Meadows
Grand Gerbil Poohbah
Silver subscriber
 
 
Posts: 3152
Joined: Mon Oct 08, 2007 1:10 pm
Location: Location: Location

Re: Grounding a CRT monitor

Postposted on Tue Apr 22, 2014 10:28 am

And?
meerkt
Gerbil
 
Posts: 32
Joined: Sun Aug 25, 2013 2:55 am

Re: Grounding a CRT monitor

Postposted on Tue Apr 22, 2014 3:11 pm

meerkt wrote:And?

While the buzz didn't go away, it went down to less than half loudness and the custom microphones also have a better SNR in general (at least compared to those bottom-line things I initially bought). VoIP and Rosetta Stone are highly usable now.

I may replace the monitor with a 144 Hz Lightboost wonderpants sometime in the not-so-distant future, as the ASUS VG248QE is again in stock where I live, but right now I have better things to worry about and besides, my CRT runs fine for what I do. Plus I'd miss this high resolution I'm getting. A lot.

(As for higher resolution LCDs such as 2048×1152 or 2560×1440 or in between, I will never ever buy an LCD that does less than 120 Hz. Never settle foreverest.)
Meadows
Grand Gerbil Poohbah
Silver subscriber
 
 
Posts: 3152
Joined: Mon Oct 08, 2007 1:10 pm
Location: Location: Location

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 1:38 am

Very odd.

I vaguely recall sometime in the past I would get recording noises from some recording mixer channels. The noises were chirps synced with this or that computer activity, like HDD reading. So I'd mute everything but the specific channel I needed each time: microphone, line-in, etc.
meerkt
Gerbil
 
Posts: 32
Joined: Sun Aug 25, 2013 2:55 am

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 2:18 am

meerkt wrote:Very odd.

I vaguely recall sometime in the past I would get recording noises from some recording mixer channels. The noises were chirps synced with this or that computer activity, like HDD reading. So I'd mute everything but the specific channel I needed each time: microphone, line-in, etc.

I don't record any of that, but here's your plot twist: I can hear that directly from the CPU socket ever since I installed my AMD FX 8350. The processor itself is rock stable (overclocked too) and not really hot either, and normally you can't hear its activity unless you lean down close to the computer case. But when you do, you'll hear it, and the higher the CPU usage, the more annoying and continuous the chirps get.

I expect it's the motherboard whining for mercy or something. It doesn't really bother me because I can't hear it from where I sit and it does not seem to affect performance or stability at all.
Meadows
Grand Gerbil Poohbah
Silver subscriber
 
 
Posts: 3152
Joined: Mon Oct 08, 2007 1:10 pm
Location: Location: Location

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 5:59 am

Meadows wrote:I don't record any of that, but here's your plot twist: I can hear that directly from the CPU socket ever since I installed my AMD FX 8350. The processor itself is rock stable (overclocked too) and not really hot either, and normally you can't hear its activity unless you lean down close to the computer case. But when you do, you'll hear it, and the higher the CPU usage, the more annoying and continuous the chirps get.

I expect it's the motherboard whining for mercy or something. It doesn't really bother me because I can't hear it from where I sit and it does not seem to affect performance or stability at all.

It is probably the inductors in the CPU VRM circuitry. If the windings of the coil aren't completely immobilized they can vibrate in response to the switching of the VRM, and this vibration will change in pitch and/or intensity depending on CPU load. Other than the annoyance factor (and the fact that it is an indication of cheap inductors), this is harmless.

If the inductors have exposed windings you may be able to quiet them down by putting some thread locker or hot melt glue on them. If they are the enclosed type you are SOL.
(this space intentionally left blank)
just brew it!
Administrator
Gold subscriber
 
 
Posts: 37637
Joined: Tue Aug 20, 2002 10:51 pm
Location: Somewhere, having a beer

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 7:47 am

Man, I hate coils that whine. I must have good ears because I've amazed many coworkers by identifying dying power supplies from their incredibly annoying whine. *Walk into room* *EEEEEEEEEEEEEEEEEEEE* "Hey has your computer been acting up on you lately?" 'H...how did you know that?'

I think some PSUs do it when their caps are dying, it seems to make the coils louder and respond more to device load.
Desktop: FX-8350 | 32 GB | XFX Radeon 6950 | Windows 7 x64
Laptop: i7 740QM | 12 GB | Mobility Radeon 5850 | Windows 8.1.1.1.1 x64
SuperSpy
Gerbil Jedi
Gold subscriber
 
 
Posts: 1563
Joined: Thu Sep 12, 2002 9:34 pm
Location: TR Forums

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 7:48 am

I once had a board at work (not a PC) that would do this with network load, run a network load test on it and it screamed for mercy :D
notfred
Grand Gerbil Poohbah
 
Posts: 3726
Joined: Tue Aug 10, 2004 10:10 am
Location: Ottawa, Canada

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 8:23 am

The other thing that could be going on is that your mics are picking up the high frequency whine of the CRT and turning it into audible noise.

I'm one of those freaks that can hear the whine so it always bugs me with CRT.
Arvald
Gerbil XP
Silver subscriber
 
 
Posts: 345
Joined: Tue Sep 27, 2011 12:14 pm
Location: Gerbil-land, Canada

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 9:18 am

SuperSpy wrote:I think some PSUs do it when their caps are dying, it seems to make the coils louder and respond more to device load.

Yeah, bad caps can certainly exacerbate coil whine since the VRM is going to work harder to try and smooth out the voltage variations that the caps should be taking care of. But the coil whine itself is harmless (at least to the hardware... your ears and/or sanity maybe not so much).

Arvald wrote:I'm one of those freaks that can hear the whine so it always bugs me with CRT.

One of the (few) good things about getting old is that I can't hear CRT whine any more! :lol:
(this space intentionally left blank)
just brew it!
Administrator
Gold subscriber
 
 
Posts: 37637
Joined: Tue Aug 20, 2002 10:51 pm
Location: Somewhere, having a beer

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 9:45 am

I had a S939 motherboard with a noisy VRM cap. The noise and pitch would change based on CPU activity. Very annoying. I sold the board fairly quickly.
i5 2500k - P67 - GTX660 - 840 Pro 256GB - Xonar Essence STX - Senn HD595's
The Egg
Gerbil XP
 
Posts: 417
Joined: Sun Apr 06, 2008 4:46 pm

Re: Grounding a CRT monitor

Postposted on Wed Apr 23, 2014 12:40 pm

May I suggest a simple, cheap USB mic like this one:
http://www.ebay.com/itm/like/120882667942?lpid=82

I am not related to that seller. It's just that this mic is discontinued but actually very nice. I bought it years ago and it's worked with Windows from XP to 8.1 and probably for a long time yet as it's a generic device. Has a very convenient on/off switch that lights up so you know when the mic is 'hot'.
Sounds pretty good for a cheapo.
hansmuff
Gerbil In Training
 
Posts: 5
Joined: Mon May 17, 2010 7:00 pm

Previous

Return to General Hardware

Who is online

Users browsing this forum: geekl33tgamer, Google Adsense [Bot] and 6 guests