Just upgraded my Integrated Amp - now here a HUM out of my LUMIN - HELP


I run two systems in my home - System one is in my family room - my old Krell 400 xi died last month. I replaced it with the new Krell Integrated amp the K300i - Everything is better - soundstage is larger - highs are clearer with no harshness, bass is amazing, and midrange vocals are so real Carly Simon vocals bring me to tears! My problem is I now have a very low level pulsating hum between tracks that I cannot eliminated. I have isolated this hum to my LUMIN when i input its feed into the Krell. The low level hum follows the RCA jacks as I move them from inputs S1 to S2 to S3 on the Krell. My DVD / CD player on this system does not have this issue - it is stone silent between tracks. The only ‘odd thing’ about my LUMIN RCA inputs is they are long - 15 feet. I have my LUMIN upstairs feeding my second system via the balanced outputs. This system runs with my older Krell S550i integrated amp. The sound is stone quiet between tracks - no HUM.

i am running the Krell K300i at a volume output of 65 ( volume runs from 0 to 100). I then control my actual volume via my I pad mini via the LUMIN app. My sound is amazing , but this HUM just bothers me. Do I need to ground the LUMIN D1? Both systems get their power via two separate FURMAN ELITE 15 Power Conditioners. I am out of options. Any help would be appreciated
tom8999
https://forum.audiogon.com/discussions/yet-another-need-help-with-a-ground-hum-thread

Hum is a simple subject that only seems complex because of all the many different situations it crops up in. But hum is as simple as this: Any time you have different paths to ground you risk getting hum.

Got it?
Miller carbon - thanks for the link - I read it several times. I still have questions. First - I am not an electrician - I am a chemist - so bear with me.

1) why did my old Krell not have this ground hum issue - I ran with this set up for 8 years, and no hum.

2) to correct the hum I need to run a circuit to feed both systems to confirm they both have the same ground? OR

3) I did minimize this issue by running a better RCA interconnect from the LUMIN upstairs to the System downstairs - now using an Anticables 2.2 interconnect with better shielding. The hum is only audible when I crank up the Krell above 70 on it’s volume control.

i can live with this issue now -

4) so grounding the LUMIN chassis will not help?

thanks in advance for the education.

 

Well first there’s at least 3 different kinds of hum. First is ground loop hum which is what I covered. And yes if that’s what you have then that is the way its eliminated, by plugging everything into the same outlet. It won’t just go down. It will go away.

Then there’s DC offset hum, which is a transformer physically vibrating. This one the speakers are silent, its the transformer itself. Because of the way transformers and electricity works its also a kind of electro magnet which is why they always make that very faint hum, which is normal. Unless you have DC offset on your line, then its like the electro magnet transformer is imbalanced and so instead of a faint hum from vibrating only a little its vibrating a lot. There’s cheap power strips that will eliminate DC offset hum. Which you don’t have.

But you might have interference hum, which can happen any time a wire goes near another signal or usually power carrying wire. If you run your cable anywhere near a power line the AC in the line induces a current in it and there’s your hum. Shielding actually helps with this one, unlike the other two. And unlike the other two it would go down in level but never completely go away. Which is what you have now.

Usually the odds-on favorite when using multiple outlets is ground loop hum. But there’s nothing in the rules says you can’t be lucky enough to have the other one- or both!

Grounding the Lumin may or may not help. That's the thing about ground. What I said will definitely work. One ground always works. Every situation. Every time. But sometimes other things work, sometimes even what's wrong works. (Like one amp is fine, next one hums, nothing else changed) The rules never change just the winners and losers, yet we keep playing the game.
If you are not using both sets of Balanced inputs, use one for the Lumin.

Use some twin screen wire like Canare L-4E6S Star Quad
Wire the RCA + and common the - and screen to the shell
Wire the XLR + to 2, - to 3 and leave pin 1 unconnected. Use heat shrink so the screen cannot short either 2 or 3


When you test, start with 300i volume at ZERO!
Thanks for the additional input - my hum is weird now - it is very faint but it rises and falls when I am not playing music out of the LUMIN, and I have to crank up the Krell and put my ear on the speaker to hear it. So I guess I have interference hum. I am rerouting my cables to get them away from the AC input cables behind all of my equipment. For me the ‘Tell’ here is that I have minimized the HUM over the last days by upgrading my original RCA interconnect to the Anticable 2.2. I just used an extension cord to move my AC input into my Furman to another outlet - trying to find another circuit.  I will let you know how this adventure works out. I guess my new Integrated Amp is ‘sensitive’. I am just glad I upgraded to the new RCA interconnect from Anticables - I am hearing ‘new detail’ in multiple albums via my LUMIN.

again thanks for the education!

A hum you’ve got? When I installed my LUMIN s1, I heard a Chinese radio station. (I’m in Canada, so it could have been a local station.) I contacted the Asian distributor, and they were totally perplexed. Meanwhile the radio signal got louder and louder, first through the right channel, then through the both. Got louder and louder.till it almost drowned out the music I was playing through my system. No fun at all. 
My amps are a pair of coincident technology monoblocks. Cables are all shielded.  Never happened to my system before, through all its 30 years of configurations. 
Solution I found was to add a passive  pre to my system.  Like, the one I kept stored  in the basement and hadn’t used in 15 years. Actually forgot I still had it. Specifically, it was a Placete RVC. Plugged that in  and shut off the volume control function on the LUMIN. And went back to using the placete for volume control. That solved everything, don’t know why, I’m not technically minded,but it did.
ieales - my LUMIN cannot come downstairs as my System 1 does not have Ethernet connection available in the family room. This is why the Lumin is upstairs - I have an Ethernet connection in the wall right behind the stereo system upstairs. Plus I am not an electrician and I do not want to short anything out.
Kudelka8 - please go waste your time elsewhere.
I'm lucky to have found this thread.  I have a hum/radio station interference issue that that only occurs when I use my Mytek Brooklyn Bridge as a phono input for my Lyra Delos.  The high gain MC choice, of course, is noisier than the low gain MM choice, but both get that damn MOR radio station.  To be sure, the interference is quiet enough not to bug me when I'm actually playing music but still... My dedicated Moon LP3 phono stage, by contrast, is absolutely interference free. The thing is, I'm beginning to prefer the Mytek's sound more than the Moon's.  What's an audiophile to do?  I know!  Spend more money!
Back to tom8999

I solved my noise-with-lumin issue. Have you?
Kudelka8 - my apology - I thought your post was a ‘spoof’.

I have improved my HUM issue by at least 90 % since I set up my new Krell integrated. I will be talking to Krell tomorrow to see if their new amp design has shown this problem.

Happy Listening
Back to tom 8899

apology accepted. Same point — the noise with my lumin stopped completely when I added a passive pre-amp to my system. 
Millercarbon- I am making progress - my HUM is getting less and less. All of my AC power cords have been moved away from the RCA interconnects at The back of the integrated amp. My Furman Power Conditioner is not contributing to the hum - I shut it off and just ran the LUMIN, and Integrated Amp but no hum reduction. My new RCA interconnects from Anticables from the LUMIN to the Krell k300i I think are the best investment I have made. I am now convinced I am fighting interference hum.

Thanks for the help.
Okay so you've picked all the low hanging fruit and its nice and quiet. From here its an Easter egg hunt for what is probably mostly really bad RFI or EMI. Which are just different aspects of the same thing. RFI is radio frequency, EMI is more static sporadic. Hardly worth two terms but there you go.

Anyway the most likely culprits are electric motors, lights with dimmers or transformers like fluorescents and some LEDs, and even plain old connections. Can be just about anything. You got it down to a way lower level than my system though I can tell you that! I'd rather spend my time making it sound better than hunting stuff like this. Anyway there's some ideas if you want to go even further with it.
My new RCA interconnects from Anticables from the LUMIN to the Krell k300i
My suggestion is try the Blue Jeans Cable LC-1 for better shielding.

https://www.bluejeanscable.com/store/audio/index.htm
I’m a Chemist too! Good people...  I see two problems you have on the go. The 15 foot rca unbalanced is picking up noise as has been identified. That’s a long run for unbalanced rca cables in a possibly noise home environment. It seems you have minimized it as the other posts have suggested. Fluorescent lights and dimmers can be big contributors as mentioned. Keep the rca well away from ac cables. Well shielded cables can help as you have seen.  The second issue is “gain staging”. The lumin should be left a unity, or full volume in order to maximize the signal to noise ratio. Control you volume level at your preamp. This helps to further diminish the amount of noise in your signal.  The best would be to use the balanced Lumin outs for the long 15 foot run.
I’m a Chemist too! Good people...  I see two problems you have on the go. The 15 foot rca unbalanced is picking up noise as has been identified. That’s a long run for unbalanced rca cables in a possibly noise home environment. It seems you have minimized it as the other posts have suggested. Fluorescent lights and dimmers can be big contributors as mentioned. Keep the rca well away from ac cables. Well shielded cables can help as you have seen.  The second issue is “gain staging”. The lumin should be left a unity, or full volume in order to maximize the signal to noise ratio. Control you volume level at your preamp. This helps to further diminish the amount of noise in your signal.  The best would be to use the balanced Lumin outs for the long 15 foot run.
I solved my phono hum problem with my Mytek Brooklyn Bridge.  A Mytek techie got a hold of me via email and walked me through a simple rerouting of a ground wire within the unit. 
I wanted to give everyone an update on my situation with my HUM issue. It has now been minimized to a minor issue in my main system.

1) ground loop hum - I ran an extension cord to my upstairs system and put my LUMIN D1 on the same circuit. No improvement in hum reduction.

2) interference hum - I got the most improvement by moving all AC Cords away from my ICs. And I upgraded my 15 foot Audioquest IC to an Anticables 2.2 IC with extra shielding ($350). Dramatic hum reduction, and improvement in music detail from the LUMIN D1 the longer the new IC is in my system. Maxed my volume to 100 on the LUMIN D1 and control volume on the Krell - cannot stay in the room over 40 on the volume out of the preamp ( thanks flashbazbo).

3) DC offset hum - My LUMIN D1 came with a ‘Wall Wart ‘ External DC power supply. Just ordered an SBoost DC power supply from Upscale Audio ($399). - should have it installed this weekend. I am hoping to kill off the last of this HUM with the better DC power supply.

thanks for all the help!!
Final Update - everyone - thanks for the help. My hum is 99.9% gone. The addition of a better DC power supply to the LUMIN D1 hasn’t helped lower the hum to almost nonexistent. And I also need to comment that my streaming has never sounded better than it does now. I credit this improvement to the better IC cables from Anticable and the better DC power supply to my LUMIN D1. I have been using the SBoost MKll for a week now, and the new ICs from Anticable for 3 weeks. I get a better sound stage  and more detail out of. My Maggie 1.7is Thani have ever heard. I am sure the new Krell K300i has a part in this also.

again thank for all your help !!
Happy Listening!