Help! I need a scientist!

[ADUHF]

Fwiw, I have also posted your question here, to try to elicit a bit more input on the problem...

https://www.head-fi.org/threads/kos...age-modifications.949698/page-3#post-16288999

One question though that I don't think has been answered yet.... Are the outlets in your room properly grounded?

Also, are you using a separate DAC with this? Or is it built into the E90 amp? If the DAC is separate, then maybe that also needs to be looked at as a possible source of the grounding noise.

 

[PointyFox]

Fwiw, I have also posted your question here, to try to elicit a bit more input on the problem...

https://www.head-fi.org/threads/kos...age-modifications.949698/page-3#post-16288999

One question though that I don't think has been answered yet.... Are the outlets in your room properly grounded?

Also, are you using a separate DAC with this? Or is it built into the E90 amp? If the DAC is separate, then maybe that also needs to be looked at as a possible source of the grounding noise.

Signal chain:
Computer -> Optical -> ungrounded DAC -> RCA -> Energizer (DC adapter powered)

All equipment are being fed off of battery power converted to pure sine wave AC.

 

[AudioCats]

The easiest way is to ground the DAC, which then will ground the E90 via the E90's RCA jack. If you want to do it on the E90 end, ground the barrel of power supply plug. Both power input barrel and RCA jack are connected to the ground line in the amp.

 

[PointyFox]

Try connecting the E90's RCA jack to the house ground. Or the barrel of power supply plug. Both are connected to the ground line in the amp.

Yeah, that would solve the problem but I don't know of an easy way to do that.

 

[bigshot]

All equipment are being fed off of battery power converted to pure sine wave AC.

Siren goes off. That is your problem most likely right there. Your inverter is introducing grounding issues. When you said you were running off battery power, I thought you meant the batteries in the DAC and amp. Plug into the wall instead and you won't have this problem.

 

[PointyFox]

Siren goes off. That is your problem most likely right there. Your inverter is introducing grounding issues. When you said you were running off battery power, I thought you meant the batteries in the DAC and amp. Plug into the wall instead and you won't have this problem.

I tried it in a few other locations, all of which were directly into the wall and the problem was the same.

 

[bigshot]

The only way you are going to solve this is to do tests for a purpose. You need to deduce where the problem is. Randomly trying different things answers no questions.

Try it in a totally different part of the town. That will eliminate RF from a transformer or radio station near your home.
Try it plugged in somewhere else. That will eliminate funky wiring in your house.
Run off of the internal battery in your player if it has one. That will eliminate power grounding issues.
Try running with the fewest possible components and see if the problem is still there.
Plug your components in with friends' systems. Swap in and out to deductively figure out which component is the problem.

That's the way you solve problems like this. I don't want to suggest that you buy anything to fix the problem until you can clearly test to find out what the problem is. I can probably point you in the right direction, but you have to do your part. Ground loop problems need to be tracked down. They don't fix themselves. If you don't really care, then I don't either.

 

[AudioCats]

Yeah, that would solve the problem but I don't know of an easy way to do that.

if you have a power strip with metal housing, the metal housing is usually connected to the ground wire (via the AC plug). Run a wire between the DAC housing (one of the mounting screws) to the power strip metal housing (mounting screw).

(the power strip needs to be plugged into a normal AC outlet)

 

[bigshot]

He’s running off an AC power converter off a battery of some sort.

 

[AudioCats]

for the whole house?
Even in a solar system there is some kind of copper rod installed into the ground I suppose?

if a "normal" ground is not available.... try connecting the DAC's metal housing to the sink (metal sink ->metal faucet ->water --> metal water pipe underground somewhere --> earth)

 

[PointyFox]

I'm running off a double conversion UPS.

 

[bigshot]

I just did a bit of googling, and I found something that said that pure sine converters require a ground spike. Have you done that? That is probably your problem. You need to run a ground cable to earth. Your converter probably has a ground post to attach that to.

 

[PointyFox]

I just did a bit of googling, and I found something that said that pure sine converters require a ground spike. Have you done that? That is probably your problem. You need to run a ground cable to earth. Your converter probably has a ground post to attach that to.

My converter plugs into the wall and uses its ground wire. What you read is probably for DIY off grid stuff.

 

[bigshot]

The thing I read said one model required a direct earth grounding. It's clearly an issue with the converter or the computer. I would try unplugging both completely and just plug in your audio equipment. If the hum goes away, I would know how to approach solving it.

 

[PointyFox]

The thing I read said one model required a direct earth grounding. It's clearly an issue with the converter or the computer. I would try unplugging both completely and just plug in your audio equipment. If the hum goes away, I would know how to approach solving it.

The thing is I tried other locations and had the same issue. I don't think EMI would reach 80+ feet especially since the hum is only present when either plugged directly in, within about 1 cm from the amp, or directly touching my desk.