**** today, i just fried two onboard soundcards.

I was using AudioTester to measure t/s parameters of speakers (i posted it earlier in here). It worked beautifully, but today didn't seem to be the case...

I hooked up my cables as usual (line out -> amp -> speaker + calibration resistor -> line in) and hit Start. For some reason the graph looked wrong. I restarted the program, and then it froze. I unplugged the line input and reconnected the amp to the speakers - white noise coming out of the speakers, no audio programs would work. Rebooted and found "Realtek Digital Output Device" set as default. Checked the control panel - all analog jacks were greyed out. Reinstalled driver to no avail. Yup, my onboard soundcard is officially fried.

Tried my laptop, running on battery power as laptops usually have issues with sound input when the power brick is connected, wired everything up, calibrated the levels okay (at this point the amp output was hooked up to the soundcard input with no issues), when i connected the speaker and put everything together, i saw a spark as i plugged the line input cable into the laptop. Luckily i only busted the external mike/line input, playback and internal mic are still good, but still, i needed that input. **** it.

Now my money will have to go towards an X-Fi that i did not need, money that should have bought new speakers. That Realtek HD really was good. And funny thing, there is nothing wrong with my amp. I still have NO IDEA how this happened, and the hardware that worked flawlessly for measuring huge subwoofers blew on this ****ty little midrange that only needed its frequency response graph plotted for crossover design.

What a wonderful day.

Could be, but i can't find one around here, i'mma have to buy it online. With all the fun i've had with my country's postal services, i'd rather not. Maybe it's just time to invest in a high quality multimeter and just use that for measuring. The only problem, would be that here there's AC voltage in the air.

The main reason why i stopped using the meter is that from time to time it would go crazy, and i would have to wait several hours till the interference settled. Sometimes i feel really weird when sleeping and have these awkward dreams, sure enough, my sleeping place measured at over half a volt. I'm serious. I sleep with my head the other way since, and i've had no more sleeping issues... In some areas of my house there's more voltage floating in the air than if i put the meter next to the TV, and that's not something i can control. It's not any of my equipment causing it.

Only bridged amp outputs float. My amp is unbridged, it ties the negative side to ground. Also, it was always connected the same way (the cables and the calibration resistor were soldered together), so the outputs couldn't possibly have been swapped.

As i said, wired directly to the line input of the laptop (for level calibration) nothing bad happened, so i'm sure it's not the amp nor the cable. There are only two other variables - the resistor and the speaker. How in the world could those generate enough charge to zap my soundcards, i don't know. All i know is that i will be using that multimeter again.

As far as the laptop goes, there could have been DC on that jack, since it is a combined line/mic input, it could have had phantom power. I do have another laptop, i'll use that one when i need to record something, so it's not that big of a loss, but still.

EDIT: No DC, but if i connect the signal cable from my laptop to my amp, both ends of the resistor measure a healthy 20v AC potential from the laptop's input "ground", that's with no signal applied. Boom there goes my input. Note to self: Use multimeter even on signal cables.

I still don't get why the PC soundcard broke completely, no voltage potential between it and the amp. The speakers even click when the driver kicks in at boot time, it just thinks there's nothing plugged in. Maybe i can override this jack detection, hmm...

I have no idea of the frequency of the electromagnetic radiation (i was wondering myself but i don't have a scope, and the freq meter of my multimeter isn't sensitive enough), and there are no power lines above my apartment building, nor any cellphone towers. There is something in the back though, it's a small concrete enclosed building that makes a constant buzzing noise (most of the time it's low, sometimes it gets louder) and has electrical panels on one side. I have no idea what it is, as the main power distribution station for my area is a few blocks away, but i do know that i can't sleep properly when that thing gets loud, and it's not the audible noise bothering me (as it's almost zero when i close the windows).

I've never had trouble sleeping at my grandparents' place (or anywhere else for that matter), but i'm afraid it's going to be a while till i'll be able to move out, as my grandparents live in another town, and i'll be going to college next year, which means i'm staying here in Bucharest, as this is the capital city, and of course, the most opportunities are here.

As in having its own ground wire, no. It only has a two-wire prong. But the amp's case and internal ground connection has been tested at zero voltage referenced to mains ground. If there was a ground loop, i would have heard it in the speakers. And as far as i know, grounds don't just disappear out of the blue - but again, this is Romania and ANYTHING is possible.

Also, i know how to install a soundcard... But an X-Fi costs a lot of cash. For that money, i can buy a brand new motherboard with a higher performance chipset, and the same Realtek HD Audio. I can get a P45 chipset board (i had a P35) so i can just drop the rest of my hardware in. I will be going the new mobo route most likely.


This is Romania. If you aren't familiar with it, all i have to say is: If i tell the utility company there's electromagnetic interference in my house, they'll tell me to go see a psychiatrist.


No surge suppresor unfortunately... But surge supressors are simply regular sockets with a couple Y capacitors slapped inside. My computer power supply already has those capacitors inside. I think i need an UPS, that would be better than a simple surge suppressor. I am looking to buy one soon.

I'm on 240, but it's not 2-phase. The electrical system was rebuilt last year when we renovated the place, new wall sockets and everything, and the washing machine or fridge generate no interference, which means the ground is good. The wiring was done by a qualified professional.

Though, i don't want to see what's inside the walls. Replacing the wiring in the walls would have meant basically rebuilding everything from scratch, something we couldn't afford, as it would have taken way too much time. And i think that before a short has a chance to initiate a fire, it'll pop the breakers. Yes, at least i have proper breakers.

Yup my bad, forgot about the MOV. My computer PSU has one of those too, so i don't think it would help greatly. I still wanna get a full-blown UPS.

Anyway, finally good news. I've gotten my old computer back in one piece again, it's a machine i built for fun a few years ago to see just what i can do with it, and mind you, i did a lot.

What Core 2 Duo? What 8GB RAM?? Here goes the oldschool.

Asus P55T2P4 mobo
Pentium-MMX 200MHz overclocked to 292MHz, running at 3.5v core and kept below burning temperature by means of a large Athlon cooler
96MB SIMM memory running WAY faster than it was supposed to
2MB ATi video card
13GB Seagate HDD
The almighty Sound Blaster 16 ISA
3Com Etherlink III 10mbit network, yup, ISA as well

Ever seen a ~300MHz Pentium 1? Me neither. Mine could very well be the only one in the world. This thing is 3x faster than the Dell P4s we have at school, i'm serious. Yes my HDD sounds like farting, and yes it's got one of the crappiest keyboards in the world, but it runs well. It's even got USB!

I have installed Windows 2000 Pro and have gotten AudioTester to run. With rather high latency, but the results are good. Now for the ground-breaking news. I knew i wasn't gonna break the SB16, as it's the largest soundcard i've ever seen, no way a bit of AC is gonna hurt it. But i played it safe and tested the cables for voltage before i connected the speaker.

All fine, except one thing. With one probe of the meter on the tip of the RCA that was supposed to go into line in, and the other in my hand, the voltage jumped over 12v AC. I realized that i was sitting with one foot on the carpet and the other one on the floor - i moved both my feet on the floor and it dropped to ~2v. I carefully connected the cables as not to touch them, and was able to measure both that damn midrange and another 12" woofer without any hitches.

So there you have it, the source of the issue was me. I do remember touching the wiring when i blew my PC onboard, as i was pulling at the wires testing for bad solder. Now, why the heck did i have a 12v potential above the amp's output cable, that's a different matter. I think the interference could have something to do with it.

Thanks for appreciating my English - when i was 5 my father went to the UK, and he brought me lots of English books and tapes to learn from, and he'd stay with me and teach me English twice a week. That's how i know it so well.

Yup. I've built myself a grounding wrist strap, now let's hope there will be no more issues with that. I didn't believe in ESD damaging components, that is, until now.


Good one.


I wasn't born back then you know.

But i remember that my older cousin had a "HC". It was a Z80-based gaming computer built here in Romania. It would hook up to the TV and use regular cassette tapes to load the games. I was so little when i last saw it, i was thinking those little green people moving on a black/white background were so cool.

Anyway, since i've had my first computer till now, i have formed a solid opinion - while Moore's law says that processing power doubles every two years, i have found that software slows down proportionally. Thus, you don't really do more work with a new computer, it just looks prettier.

Okay, got it. But doesn't that resistor act as a voltage divider, potentially frying more stuff (me included)? I ask because with the amp hooked straight to the laptop there was no problem, when i went through the calibration resistor, boom.

Besides, it's not like i'm working with mains voltage. If mains voltage would be getting thru, i'd be in trouble, wrist strap or not.