I need your help to get rid of a ground loop
Jan 20, 2004 at 7:21 AM Post #16 of 38

jefemeister

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if you break the ground on the audio cable it might be good to tie the two chassis together with a single wire of respectable gauge. Not essential though.
 
Jan 20, 2004 at 7:29 AM Post #17 of 38

Edwood

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Nope. Brickwall ---> CyberPower UPS ---> PC = no workie.

Gonna power down and try another UPS.
rolleyes.gif


-Ed
 
Jan 20, 2004 at 7:45 AM Post #18 of 38

Edwood

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Crap. No luck on the other UPS. I guess I could try to plug my PC into the P300.
eek.gif
The P300 would probably explode.

Could be the power supply. I will try another power supply later. It's upgrade time for the strained PSU. It's on it's last leg.

Hmmm. It won't be stable for long, but I'm gonna try plugging the PC into the Brickwall without a UPS.

-Ed
 
Jan 20, 2004 at 7:49 AM Post #19 of 38

Edwood

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Have you tried unplugging the analog IC from the RME PAD, Peter?

The only buzzing I get is from the RME PAD. I can only hear it if I crank the volume up to a level that would make my ears bleed. But you know how picky I am.
mad.gif


Hmmm. If I still can't get the damn PC to work right, I do have a small PC that will probably be low power enough to plug into the P300, it has one PCI slot, RME PAD will fit fine there. I know it's crazy, but I have alot of headroom left with the P300.
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-Ed
 
Jan 20, 2004 at 8:11 AM Post #21 of 38
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Well the hum I used to have was only there when the amp was connected to the computer. Now after the Ratshack tweak that hum is gone, replaced by a much quieter noise floor, that still has a faint hum, but only at max volume with low impedance cans. Nothing that I need to worry about, but you can be as paranoid as you want, I suppose
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Jan 20, 2004 at 8:15 AM Post #22 of 38

NeilPeart

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What do you mean "amps don't play nice with the Brickwall?" I am interested in buying the Brickwall to replace my isobar ultra, but this comment has made me wary. Please elaborate. Regarding the hum, I just said screw it and stopped using my UPS all together for my audio system. Though it was a high-quality APC unit, the power it provided was not good for audio at all. I currently plug my PC directly into the isobar surge protector, along with the amp (I know they should be on separate lines, but financial/space issues prevent this). I'm not too worried about power spikes because black-outs/lightning storms are rare around these parts (and all my data is stored on my server, which is connected to an industrial-strength UPS system). Good luck with your power issue.
 
Jan 20, 2004 at 8:20 AM Post #23 of 38

Edwood

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It's the UPS. Either one. Damn.

1. With the Mains ---> Brickwall --> PC = Greatly reduced buzz. It's so quiet I can only hear it with my Etys plugged in and the Grace cranked all the way up. (Gain switch on). This would surely make me deaf. I can't hear the buzz with my K1000's.

2. With the Mains ---> Isobar Surge Suppressor (MOV) --> 1920VA Powerware UPS --> Belkin Isolator Surge Suppressor (MOV) --> Brickwall --> PC = Reduced buzz. Very quiet. Can only hear it with the K1000's if the room is really quiet. With the Ety's I can hear is pretty clearly with the volume cranked up. (Gain off).

3. With the Mains ---> Isobar Surge Suppressor (MOV) --> 1920VA Powerware UPS --> Belkin Isolator Surge Suppressor (MOV) --> PC = Buzz. Can be heard clearly with the K1000's with the volume turned up all the way. (Gain switch on). quite loud with the Ety's. (Gain switch off). At normal listening levels, I cannot hear the buzz with the K1000's. (Nothing playing)

4. With the Mains ---> 500VA CyberPower UPS --> Brickwall --> PC = Buzz. Same as #3

5. With the Mains ---> 500VA CyberPower UPS --> PC = Buzz. Slighty more than #3 and #4.

Ugh, I guess this leaves me with trying another power supply, or the more drastic solution of building a dedicated music PC plugged into the P300.

Hmmm. Anyone know where I can find a linear regulated power supply for a computer? One that outputs +12, -12, +5V, +3.3V with at least a 100 watt output. ?
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-Ed
 
Jan 20, 2004 at 8:30 AM Post #24 of 38

Edwood

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Oh, I've heard that it's not a good idea to plug a Series Mode Surge Suppressor like the Brickwall into an MOV based one, due to the fact that MOV based ones dump crap into the ground line.

Oh, and the MOV will bite the dust first, and probably catch fire if you don't replace it. But only if there's a big spike.

Brickwall specifically warns against plugging it into anything other than the wall mains. The Brickwall is supposed to be the first line of defense anyways.

NeilPeart :

It is well known that the Brickwall compresses soundstage and reduces the dynamics of amps. The more power hungry the amp, the more noticeable. It is more of an issue for big power amps. It is much much subtle with headphone amps.

But the Brickwall is an amazing noise filter. But it is first and foremost a Surge Protector. And one of the best ones money can buy. The Isobar doesn't eve compare. Plus I hate Tripplite Isobars. Mine has an annoying coil buzz when higher current is drawn. Electrical noise is reduced, but acoustic noise is added instead. The Belkin Isolator is much better than the Isobar. Dead silent, no coil buzz. But, the Brickwall is even better in all regards. Well, except for the afore mentioned amp issue.

-Ed
 
Jan 20, 2004 at 8:51 AM Post #25 of 38

NeilPeart

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I'm glad you're getting somwhere with your power issue. Thanks for the help with the Brickwall. Where can I find one for a good price? Thanks for all the help.
 
Jan 20, 2004 at 9:50 AM Post #26 of 38

Jasper994

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Quote:

Originally posted by Edwood

Which Rat Shack thingy did you end up getting, Aaron?

CRAP! I do however have the buzz coming from my RME digi96/8 PAD. I have to turn my Grace all the way up to hear it. If I unplug the 1/4" adapter with everything still plugged into it, Silence. If I switch to digital input. Silence. So all the noise it coming from the PC. I'm going the PC to a better UPS. It's running on a crappy 500VA CyberPower UPS. Better yet, I'm gonna try hooking up the Brickwall to the mains, and plug that UPS into the Brickwall.

-Ed


uhhh part number 270-054 (I think that's the right number) It's called a ground loop isolator and it was $15 It's the first one in the links Peter posted.
 
Jan 20, 2004 at 9:57 AM Post #27 of 38

Jasper994

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BTW there is still a little noise in the line but I'll never have the headphones up loud enough to hear it, so why worry about it...
 
Jan 20, 2004 at 1:52 PM Post #28 of 38

lan

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Another reason to use an external DAC connected via optical
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Jan 20, 2004 at 4:49 PM Post #29 of 38

Edwood

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Quote:

Originally posted by NeilPeart
I'm glad you're getting somwhere with your power issue. Thanks for the help with the Brickwall. Where can I find one for a good price? Thanks for all the help.


Where to buy Brickwall

I've bought two Brickwalls from them. They drop ship from Pricewheeler, so it will ship from San Diego. This was a big bonus to me, as I live in Los Angeles.
wink.gif


Although, I'm eyeing the Minuteman Online UPS's Sellcom.com carries.

Kinda pricey, but I'm considering it for my server. I'll have to see if there are more competitive models out there. They claim these UPS's have a smooth true sine wave. But I wonder how clean they really are.

-Ed
 
Jan 20, 2004 at 5:41 PM Post #30 of 38

NetRunner

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One other computer UPS to consider could be the Powerware 9000 series (double-conversion online).. Has cooling fans (i.e. definitely not silent). Also saw a review for audio use.
Minuteman though does advertices DSP circuitry.. Hmm.. THD still max 2%. Also Powerware says THD <2% on linear load..
 

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