Sorry, but where are you located?
Here in Sweden the power sockets allow the cable to be rotated, hence the opportunity to connect live to neutral and vice versa. This, in itself can cause hum and other issues.
Can you connect the Lumin and power amp to the same extension box?
That response came from Le On. I still have no idea what cable or cables connect from where to where. Everyone mentions ground, but what specifically does it mean. So there is LUMIN main unit, its separate linear powers supply, and the Amp. I use three cables? What kind of cables? And what inputs and outputs do I connect in which device? Thank you
I am in US. To the best of my knowledge, we don’t have that stuff. Cheater plug?
Observe that on both the Lumin player unit and the PSU, there are connectors that are marked GROUND.
Google “ground cable”.
We are making progress. Saw the connectors on both LUMIN units, and used my Google machine to discover THE ground cable. Now:
1 - There is no such “ground earth” connector on my Rotel Amp RB-1590. As I previously said.
2 - How do I make the connection?
Thanks
If you have a spare RCA connector free on the amp, this may do it, for something available off the shelf:
As long as the RCA connector is connected to chassis ground - it usually is but best to check this, as well as grounding this amp in general, with Rotel before trying this, if you can… It’s always best to check with the manufacturer, just for peace of mind.
To clarify: there was / is no hum issue with the Rotel Amp alone. The hum comes into play only when the Lumin is connected directly to the Rotel Amp. Even when the Lumin PSU is off. Also, there is no hum when I connect the Lumin to a preamp first, then from preamp to Amp.
There are ground earth terminals on both Lumin main unit and its external PSU. There is no ground earth terminal on Rotel Amp, but you are saying I can use the RCA terminal.
So three units. How many cables do I buy, and how do I make the connection?
I think Lumin support are checking that you have all your HiFi on a common ground, to try and minimise groundloop issues.
Are you using a powerstrip/powerboard? Is EVERYTHING plugged into the single powerstrip? Or do you have 2 separate powerstrips in use, with your HiFi gear?
If you can, have all (DAC, pre, power amp etc) HiFi gear on the same powerstrip (make sure the powerstrip current rating is up to the task of your gear of course).
I think 1 x Groundhog could help. You just need 1 x IEC cable with earthed plug for your country, which plugs into the female IEC inlet of the Groundhog. And then this Groundhog + IEC cable goes into the same powerstrip as your power amp and DAC.
This means you need to use 1 x RCA connector on your power amp - so you’ll have to go back to using XLR cables for this test.
See if you can buy on Amazon with a 30 day return policy so you can return it if it doesn’t work.
I do also like Peter’s suggestion to use passive volume control with a pre-amp but maybe that can be a next step.
As Peter also suggested, you should ground both the T1’s PSU and DAC as well. Actually that alone may solve it. Difficult to predict without trying.
Thank you very much!
I think I will give it a shot! Groundhog is available on Amazon USA at $50 sold by iFi as third party, so not sure of return policy, but I can check.
Right now, everything in my stereo set up (dedicated) is plugged in a single power conditioner - Isotek Polaris.
If this does not work, I have my eyes on a Parasound Halo P5 as a preamp in Analog connection.
No problem! Let us know how it goes. I’m quietly confident this will solve it but it’s impossible to know for sure until you try.
You could even use the Groundhog on one of the T1’s RCA outputs.
But a grounding cable between the T1 and it’s PSU is also a good idea, as Peter suggested.
You mean one grounding cable between their Earth Ground terminals? See pics.
Can I use any cable for this? Meaning don’t have to wait for Groundhog?
Yes that’s what I said earlier - trying that first (as per Peter and Lumin) may actually solve the issue without the need for the iFi Groundhog !
Big breakthrough!
Connecting a cable between the Earth Ground terminals on Lumin and its PSU did nothing.
But then, I removed the RCA outs to subwoofers, and connected them to Rotel Amp RCA ins. No noise! Zero!
Rotel Amp is still used in Balanced mode with switch flipped to Balanced, and connected XLR out on Lumin to XLR ins on Rotel.
The issue is: cannot use the subs, as they were previously used on Lumin T1s RCA outs.
Ideas?
Also flagged @wklie
Scratch that!
PSA subwoofers seems to be the problem. Removed RCA cables completely from Lumin to anywhere. Just XLR to Amp. No hum. PSA subs are to blame. No grounds on them. Need to ground them. See pic
Good finding. I didn’t realize a subwoofer was involved all time - this really complicates the situation, and all previous suggestions about grounding the Lumin player + PSU + amp probably would not help as it missed the subwoofer. If you had a working setup of Lumin + pre-amp + amp + subwoofer, I suspect the pre-amp may be the only solution. If your sub-woofer has a high-level input, perhaps you can try the high-level input instead of RCA and see if that makes a difference. I’ll talk to my coworkers on Oct. 3 and see if they have any better ideas.
Thanks Peter! I look forward to the input from your support team. The PSA don’t have a high level input, just RCA. See pic.
I wrote Tom over at PSA. Hopefully he has a solution.
Special thanks to @dabassgoesboomboom! You really put me into research and troubleshoot mode!
If the sub can only use RCA input, perhaps you may try using the Lumin RCA output for both subwoofer connection and amp connection, via a RCA one-to-two Y-splitter. (Avoid the XLR in this setup.)
I checked with Tom Vondhel of PSA. According to him:
… the subs have no ground, they are internally grounded(double isolated). But there can still be looping feedback through the AC without the ground pole…
So I am completely lost now.
