[pyromnd]

Hey everyone, Pyro here. New Here and Im a newbie to good stereo equipment, but i have everything working except for this damn hum.

So for my sound system, I have a sundown car woofer hooked up to a 1200w car speaker amp, powered by 850w computer psu. It has a ground loop isolator on it. It needs it, or it alone has a huge buzzing noise coming off. (That got rid of that hum)

My problem is, i am now listening to records. My record player is a crosley, it has a pre amp built in(no ground nut), but i have a tube phono amp that i have the turn table use phono mode with.  when i plug this phono amp in, i get a slight humming again. once the amp is unplugged it goes away.
If i unplug my 3 pronged outlet sub setup everything is fine. If i remove the phono amp and use the built in amp on the crosley every thing is fine.

I would like to keep both amps. What can I do?

[ArthurDent]

Greetings & Welcome to AC Pyro     There are some very knowledgeable folks here, who I'm sure will be able to suggest some solutions. Good luck on a speedy resolution.

[Phil A]

Welcome!  Out of curiousity, do you have a cable box in the room?

[pyromnd]

no cable box in the room. Also, all of my sound system is plugged into a power strip.

[toocool4]

Welcome to AudioCircle pyromnd

Are you able to defeat the phonostage in the turntable or are you just plugging in something that is already line level into the phonostage? If that is the case, you will have issues.

[FullRangeMan]

Welcome to AC 

[GeorgeAb]

Welcome Pyro.

I would try one of those cheezy 1 to 1 isolation transformers. https://www.amazon.com/InstallGear-Ground-Isolator-Noise-Filter/dp/B077Y5DLBB/  If it resolves, I would then look at a Jensen ISO Max. I use the Jensen ISO Max for my subwoofer amps to resolve hum which works well.   

[WGH]

Welcome to AC Pyro. Your problem could be as simple as a ground loop. Use a cheater plug on one or both amps to see if that is the problem. All my AVA electronics have a A/C ground lift switch on the back, the recommended position is OFF so the audio circuit ground is disconnected.



The cheater plugs are $1.00 each or try a Synergistic Research Quantum Ground Lifter (shown above) with a cool looking lightning decal ($44) for a total of $45.00 ($1 plug + decal) from The Cable Company
https://www.thecableco.com/quantum-ground-lifter.html

Here is a hum eliminator I haven't seen before: Ebtech Hum X - Plug-Style AC Voltage Ground Loop Hum Eliminator
Amazon has the important return policy on this model. I discovered there are plenty of hum eliminators that look like this, some cheaper, most reviews say they don't work but some people like them.
https://www.amazon.com/Ebtech-Hum-Plug-Style-Eliminator-Cleaning/dp/B07W682STV/ref=pd_lpo_1

[Phil A]

I have a Hum X.  Mainly used it in my old house in the basement system.  Eliminated the little bit of hum I got (seemed to be a think between the subwoofer and projector - pic below).  It was an integrated AV system with lots of components.  There are other devices but it is best to eliminate the hum by properly grounding the components.  The 2-prong adapter can cause issues - https://www.advancedelectricalcompany.com/electrical-articles/is-it-safe-to-use-plug-adapters.php#:~:text=If%20an%20electrical%20surge%20does,demand%20of%20today's%20electronic%20devices.

[WGH]

I have a Hum X ....  There are other devices but it is best to eliminate the hum by properly grounding the components.  The 2-prong adapter can cause issues.

Phil - have you checked to see if the ground pin on the Hum X is connected to ground?

Using the cheater plugs would be for proof-of-concept to find out if there was a ground loop. If a house is properly wired they should not be a hazard unless the stereo is next to the bathtub while you're in it.

The hot and neutral wiring was random in an old house I rented. Outlets and light switch connections were sometimes reversed, everything was hot all the time. Back in the old days 2-prong plugs weren't polarized either, it's amazing we all survived.

[Phil A]

I don't think I'm currently using the Hum X.  Had the issue in my basement and gave it a try and it resolved my issue (and I moved over 8 years back).  I am using Class D amps with my Rel subs (except for the upstairs bonus room which is basically a guest bedroom).  Rel advises just to connect the positive from the Rel Speakon Cable lead to the amp - https://www.youtube.com/watch?v=3F5WTOu60hE   In one (2-channel) system, I have a Sumiko S.5 subwoofer, which is a copy of a Rel T5 as Sumiko used to distribute Rel.  In my main system, I recently got a pair of Rel S/812s (formerly had 2 Rel Storm IIIs - one still works).

In the spare system, I have a Class D Audio mini GaN amp (being fed via a Teac UD-503 DAC with volume control and the Teac has an analog input and I have an Oppo 103D connected to a modded Sonic Hologram Generator via the analog input and a mini PC running JRiver into the Teac's USB input) and had hum.  The sub gets its signal from the amp and I connected the RCA input of the sub to one of the unused multi-channel outs of the Oppo 103D.  Had a hum before that and it was gone.

I also (per Rel's recommendation) have an unused input in my my main system preamp connected to the Rel.  I had not experienced an issue but did it anyway.  One other thing someone can do is make an RCA cable with just the ground connected (if it was easy to get one without the center pin one could do that do) and connect something like a source and a preamp (and I may give it a whirl for kicks as the main room will get painted in the near future and everything has to come apart anyway - don't want to even think about it now).  It is an inductive load vs. a conductive one and in theory I'd guess could help with ground issues.  That would be the cheapo way to do vs. buying something more expensive.

There are tons of articles on grounding - e.g. https://www.planetradiocity.com/how-to-ground-your-audio-equipment   or   https://www.diyaudio.com/community/threads/audio-component-grounding-and-interconnection.163575/   or   https://www.quora.com/How-do-I-ground-audio-equipment    I'm sure there are tons of others as well.