Just got the Lumin T1 today.
This looks gorgeous! Fantastic built, great display and full MQA compatible.
Sound wise, first impressions are very positive. Has this very “analog” , sweet sound.
One thing I noticed is that when connected directly to Amp, noise floor / hum goes through the roof. I can’t explain for sure why or where the noise came from, but I’m guessing it was due to the lower voltage output from the T1 when using it’s internal volume control.
Put back my DSPeaker Anti-Mode in Analog only, and hum went away completely. Although the extre A/D/A conversion on Anti-Mode makes me uneasy.
I am thinking of getting a purely passive and analog preamp for volume control only, such as Parasound P5.
Nice. Are you using balanced XLR interconnects or unbalanced RCA?
Balanced XLR all the way!
Lumin T1 looks solid built, I’ve large collections of DSD, can it playback DSD128 and DSD256 without down-sampled via Roon?
Lumin A1 / T1 / D1 supports DSD64 only. Higher DSD rates will need to be downsampled.
This is unfortunate as I also do Roon’s DSP up-sampling, up to DSD256 from most listening sources including Tidal streaming. Lumin is a great product and hope this can be incorporated in the future. Thanks!
I realize that fully balanced is what you want to use. Just give it a try with a simple pair of RCA?
I once had a VTL TL5.5 Signature Series II which gave me a headache as it was impossible to make it work balanced with my Karan power amp.
The combination produced a horrible hum and hiss. Didnt even matter if the pre was on or even connected to mains… I think i came to the conclusion that different ground planes came into effect when connected with balanced cables. With RCA it sounded just fine, and quiet when it was supposed to.
Great idea. I will try it tonight. It doesn’t hurt to try I guess. Thanks.
Just tried it. Noise is down quite a bit, but still there loud enough to bother me
Sorry, was worth a try though. I suppose you have tried checking phase on power supply cabling etc?
And if possible disconnect ground on either of the Components?
Check to make sure your balanced connections are compatible. Some manufactures can follow different conventions regarding pinouts.
But there is no noise when using Lumin to preamp then preamp to amp. So it should not be any phase or grounding issue
They all fit. So Rotel RB-1590 amp and Lumin T1. How do I check for compatibility?
There are two conventions for pin outs which assign different pins for hot, cold and earth. Just check they are the same.
It should be in their respective hand books. Also check the gain to see if it can be adjusted.
Above is from previous reply from @wklie
Any suggestions on these attenuators?
From what I can read, the heightened noise floor experienced when connecting the Lumin T1 directly to Amp (Rotel RB-1590) is most likely impedance mismatch and/or attenuation / gain issue.
From Lumin T1 website: XLR balanced, 4Vrms, pin 2 Hot
From Rotel RB-1590 website: cannot find anything:
Google does say PIn 1 screen, 2 hot/in phase/+ 3 cold/out of phase/- so it looks ok.
I was considering if your preamp galvanically isolates the ground planes in a different way which takes care of the issue.
If you have a multimeter, measure any AC voltage differences between the cases of the Lumin and your Rotel?
That was the issue in my case. One of my units were passing power ground to chassi ground via a resistor, the other had a different method of grounding the chassi.
Funny you mentioned this. I receive the following from Lumin support:
If possible, please also connect both LUMIN PSU and main unit’s “Ground” connector with the power amp’s ground on the same ground socket.
Although I have no idea how to do this. A three way cable going where?
I think it means you need two ground cable to connect to the amp ground. That response did not originate from me. I’ll try to get this clarified (or have support send you a clarification) by Oct. 3 since Oct. 2 is not a working day for us.
Since you tested that a pre-amp gets rid of the hum, you should also consider using a pre-amp, which improves the sound quality as well (as compared to digital volume).