Question Grounding issue with new sound card and speakers?

[sunofcain]

Hi,

I bought a new sound card (Sound Blaster X SE) and installed it a couple of weeks ago - I also got 2.1 speakers (PreSonus Eris 3.5 Studio Monitors with PreSonus Eris Sub 8BT).

After installation, my machine wouldn't start. Both the motherboard and power supply were fried (I built the system 3 months ago with quality parts). I replaced the motherboard (ASUS ROG STRIX Z790-E GAMING WIFI) and power supply (Thermaltake Toughpower GF A3 1050W) and the sound card worked fine. Then today, when I went to start my computer, it blew a fuse, so I plugged it into another circuit and it blew that fuse, too - just as soon as I plugged it in, I didn't even push the power button.

Today, I bought a new power supply (Corsair RM1000X) and installed it. The computer started after hiccupping a few times. When I went to plug the Bluetooth subwoofer into my Sound Blaster X SE, it made a really loud electrical/speaker noise (the computer was turned off), so I'm thinking that the sound card was bad, so I took it out.

When I tried plugging the speakers into the onboard sound output, I got the same noise. It is really loud and I'm afraid if I plug it in it will fry this new power supply.

I'm using Bluetooth to connect the speakers now, but wish I could use the new sound card I just bought. I also am afraid that this new power supply will die too unless I find out what the grounding issue is.

Can anyone help with this? I have built many computers but haven't run into this specific problem and I'm not sure if it's normal to hear that loud sound (with studio monitors/subwoofer) or if there is a short in the system. Any help would be appreciated.

Current setup:
CPU: Intel Core i7-12700KF
CPU cooler: MSI MAG CoreLiquid E240
Motherboard: ASUS ROG STRIX Z790-E GAMING WIFI
Ram: Team T-Force Delta RGB 64GB (2 x 32GB)
SSD/HDD: SAMSUNG SSD 990 PRO 1TB, PCIe 4.0 M.2 2280
GPU: MSI Ventus GeForce RTX 3050 8GB GDDR6
PSU: Corsair RM1000X
Chassis: Thermaltake S300 Tempered Glass Edition

 

[stonecarver]

Are you sure your feeding the speakers with the output from the sound card and not mistakenly back feeding the amplifier from the speakers INTO the sound cards inputs.

That can sent thunderous jolt into the sound card/ PC and play havoc.

Back feed an channel on an amplifier and you blow a channel. If that's what's happening than now we also know what it does to a PC.

Again not sure if this is what's happening but I would make sure with input/ outputs.

 

[sunofcain]

Thanks for your response. I am using a single miniplug to R/L split RCA cable to run output from my computer to R/L inputs on subwoofer then the speakers connect to the subwoofer via RCA. Could the cables be the problem? And is the sound I'm hearing normal and I'm just supposed to turn the subwoofer off to hook it up. I really don't want to fry another power supply.

 

[stonecarver]

I'm just supposed to turn the subwoofer off to hook it up.

100% have the speakers/sub off when plugging into sound card.

But that does not satisfy my curiosity and say all good if from now on it's off when plugging it in. Yes do that from now on BUT.

You said motherboard and power supply had to be replaced. That's a question that needs to be resolved and figured out.

If plugging into the correct inputs while speakers were powered up you would get a quick grounding hum while inserting into jack.

to see what I mean with the speakers / sub powered ----NOT CONNECTED TO THE PC--- pinch the mini pin with your thumb and index finger. You should hear the hum change tone.

That's what happening when plugging into PC/ sound card and most of the time not a big deal.

Could you have plugged into the line in on the sound card? That would cause chaos

 

[sunofcain]

When I first installed the soundcard, I plugged into the mic jack - from subwoofer input to microphone input on my computer. I think that's what fried it the first time. When I pinch the mini pin while it's plugged into powered subwoofer, I do not hear anything at all. I have not plugged anything in the wrong way since I put the new power supply in.

 

[stonecarver]

When I first installed the soundcard, I plugged into the mic jack - from subwoofer input to microphone input on my computer. I think that's what fried it the first time. When I pinch the mini pin while it's plugged into powered subwoofer, I do not hear anything at all.

Okay were getting somewhere. Cause and effect. Now onto are you good?

The next question is did the sound card take a hit or is it still ok.

Me with what happened I personally would put that sound card in a non loved PC that if it dies it dies kind of thing and test for a repeat or proof of life.

 

[sunofcain]

The sound card worked fine between installing power supply #2 and power supply #3, but I reckon it could have taken a hit. Unfortunately, I do not have another pc to test the card on. Also, I'm still getting the loud noise after I removed the sound card. After uninstalling it, I tried plugging into MB sound output and it screamed, so I don't necessarily think it's the sound card. Could I get anywhere with a voltameter? To see if there's a grounding problem within the case, or could it be a ground loop that could be remedied by installing a ground loop isolator?

 

[stonecarver]

Could I get anywhere with a voltameter? To see if there's a grounding problem within the case, or could it be a ground loop that could be remedied by installing a ground loop isolator?

You could do some checking with a volt meter.

I would at this point bread board the whole PC out of the case and see if you still get the grounding spikes.
It could be as simple as a motherboard stand off to the motherboards back plate having the metal punchouts making contact on the inputs/ outputs in the back.

You have changed the power supply and the motherboard. The case is suspect, again maybe a standoff touching.

 

[sunofcain]

Before I installed the latest power supply, I took the motherboard out and inspected the standoffs - one of them was acting up so I removed it, would that make a difference? I didn't have any more standoffs to replace it. Are you familiar with ground loops, or ground loop isolators?

 

[stonecarver]

Old audio guy here and yup ground loops are part of the nature. PC are just another box of electronics and sometime same issues.

 

[sunofcain]

Thanks for your help, I appreciate it.

 

[stonecarver]

There is another elephant in the mix. The sub. Do you have anything that's not your PC to send music onto the sub. Does it play nice with something other than your PC? Also is your wall outlet properly grounded?

 

[sunofcain]

All I have is a little mp3 player like the one in the pic. I am charging it, will test in a bit and get back to you.

 

[sunofcain]

There were no issues with the MP3 player...

 

[stonecarver]

Electronics are weird. I was hoping that you might have something that needed to be plugged into the same outlet as the sub to see if the ground loop did the same as the PC.

But that's good news at least for what you had to test with. The mp3 player is basically isolated , not connected to your wall outlet from ground loops.

Me I would remove the motherboard from the case to be 100% sure it's not the heart of the issue. But that's me.
I have on old amp and preamp from the same company that is going on about 45 years.

The amp was made to plug it's A/C into the rear of the preamp as the amp has no power switch.

If I did that the amp's case becomes live and you can feel the jolt electricity if you put your hand on the top of the amp.

I learned that's a big no no and both work perfect to this day minus the weird grounding being plugged into the A/C of the back of the preamp.

If both are plugged into the wall no live amp case all is fine.

My concern for you is you have had to replace the motherboard and the power supply and the ground loop zap is still there.

So it comes down to the sub just hates the PC electrical wise or there is something not happy and again I lean toward the case.

At this point if you want to try that ground isolator you posted go for it and or a different cable. If that does not work than back to the case ?

 

[sunofcain]

OK, I've ordered a new cable - this time miniplug to 1/4" (sub has both RCA and 1/4" inputs). I also ordered a ground loop isolator and some motherboard standoffs. I will tear down the system again when the items arrive then report back. Thanks for your help. In the meantime, if you think of anything else, please feel free to share.

 

[sunofcain]

Also, if I set up the motherboard outside the system, how do I power it on without the switch?

Oh, never mind, I found a switch I can use on Amazon.