I have U1 Mini and use Roon. Does LEEDH processing (not using LEEDH volume control) improve SQ even if I use Roon?
I’m not sure I understand your question. Anyway, if you keep volume at 100 (with Volume Control set to Off), there is no digital volume attenuation (regardless of which volume attenuation algorithm, e.g. Leedh, is chosen), so there will be no effect on SQ.
If I want to try LEEDH processing but still use my analog preamp volume control, is it possible? And how to set it up?
You can but you would be having to use two volume controls and two levels of attenuation. It should be fixed going to the pre really, using digital volume is for times your not using a pre and going straight to power amp or headphones or you really want to use Roon to control the volume. But there are trade offs likely.
To do this, turn down the Lumin volume to a really low value, then turn up the preamp volume. If your preamp has a HT Bypass or unity gain position, you can also use it.
I have an ATC preamp SCA2 after my Lumin T2. I am using balanced connection. The unity gain for balanced on the ATC SCA2 is at 1 o’clock (confirmed directly by ATC last week). So I will set the preamp at unity gain with low digital volume on the Lumin T2 and increase sound using Roon app control.
I am intending to check and report if any sound quality improvement with my system.
I will be fine controling everything including volume from Roon app if SQ is better.
Only caveat is thinking to lower the SCA2 volume when listening to vinyl, CD or tape, which anyway is rare for me these days.
Looking forward to your report. By the way, there is a different school of thought that says the preamp volume should be set to Max (for greatest S/N ratio) instead of Unity Gain.
I just compared the Leedh volume control with the standard control on my Lumin U1 Mini and it is indeed a clearly audible difference to the better. This is a specially welcome improvement for me since I usually play at low volume and I have active speakers (Dutch & Dutch 8C) that preferably takes a digital signal (AES/EBU).
I am currently using my Benchmark DAC2 as pre-amp; toslink from the TV and S/PDIF from the U1 Mini. This setup, however, imply an extra D/A - A/D conversion since the D&D 8C converts analog input from the Benchmark Dac to digital. I was ready to order a MiniDSP SHD Studio and use as a digital pre-amp, but after hearing the Leedh volume control in my U1 Mini I am curios if there is a way to simply use the U1 Mini as pre-amp.
I therefore have a simple question: is there a way in which I can get the output (toslink) from my TV to the U1 Mini? The TV is connected to my network and I stream directly to the TV using Ethernet connection.
Thanks for any help!
Not that I’m aware of. In your setup you probably need another box to switch the input for the speakers.
Ok, thanks for the information. Perhaps a future development of the U1 Mini (which I guess is used by many with active speakers and no need for a dac) would be to add one or two digital inputs so it can be used as a pre-amp with the best possible solution for digital volume control 
@wklie
Peter, may I ask your advice for the following scenario:
I am connecting my Lumin T2 directly to a power amp. The system does have a bit too much gain and since kids use the stereo as well, I want to limit the max volume. Lets assume by roughly -4db
What is supposed to be the better choice:
- enable Leedh and use the max volume setting (I think at around 75% I get those -4db)
- or switch “Analog Audio Output Level” from “Normal” to “Low”
According to the Lumin settings description, the later runs the DAC chip in some special mode lowering the output level. But there is no word is this special DAC mode has any drawback in term of sonic quality.
What is, in theory, the best approach?
PS: great to see Lumin investing into making the digital volume sound better. I really think this is awesome and love the addition of a “max volume” setting. For those connecting a Lumin directly to an amp as I do, this is really a great feature. Thx!
BR
mark
If with this setting, you get a larger volume range to use but still loud enough for classical music, then this is better. On T2 X1 this decreases roughly 9.5dB for the XLR output voltage to drop from 6V rms to 2V rms.
If it’s not loud enough, then you’ll have to use the Max Volume % setting while keeping Analog Output Level to Normal.
What model of power amp are you using?
Hi @wklie,
We are selling the house so listening room is in visiting mode with speakers near the wall. I had briefly the chance to confirm great SQ improvement with Leedh in many aspects.
My audiophile life will be in parenthesis until Decembre. I am looking forward to the new listening room in the new home ! Should be huge improvement and freeing all the potential of my system.
2 Likes
Hey Peter @wklie . Have a question about your view of optimal use of my U1’s Leedh when used with my Chord Dave/Blu setup.
I can setup Dave to be in “DAC Mode” which fixes the output to -3db. Or I can put it in “Preamp Mode” and set the the volume anywhere including at 0db or at +19db max or anywhere in between. You noted in an earlier post:
However setting my Dave preamp to +19db leaves little to no room to control volume with the U1/Leedh as just a little volume is too much.
I’m curious what configuration would you recommend in my situation to best utilize Leedh?
@wklie
I currently own an Hypex NC500 class D based amp. Before the Leedh + max volume firmware was released, I was using -10db attenuators on the XLR cable going to the amp from the Lumin in order to manage excessive gain. IIRC this was using Analog Audio Output Level “normal”.
After the Leedh firmware I replaced the above config to use Analog Audio Output “low” + max volume 75% and enabled Leedh. I think the audio quality was improved in this setup, compared to using the attenuators.
I am now testing a Pass XA25 class A amp. With this amp (RCA only) I find that Analog Audio Output Level “low” is still loud enough for classical music and requires no max volume setting on the Lumin.
PS: the Lumin settings page states that Analog Audio Output ‘low’ reduces the output by around 4db. You wrote for the T2 it is 9.5db on XLR. Can you confirm this is correct? Also, is it the same 9.5db for RCA on the T2?
If Leedh is indeed lossless, should the “DSP Volume” in the Lumin section of the signal path in Roon be purple instead of green???
Adding @brian for some feedback.
I was wondering the same: is Limin or Leedh in talks with Roon about this?
Keep it at 0dB in preamp mode. The reason is that if you’re using Leedh volume algorithm with the Lumin, you do not want another different digital volume algorithm to modify the result of the former.
This only refers to an analog preamp, not those DAC-preamp products using digital volume.
1 Like
If I’m not mistaken, the “lossless” in the marketing material means a different thing from the lossless digital transfer of music data (in Roon signal path). My take is that refers to the scheme smartly minimizes further loss by the DAC hardware, since none of them can exceed 21 bits of resolution in measurements (see stereophile).
Please focus on the SQ, instead of the indicator color.
2 Likes
@wklie
Peter, can you please clarify if Analog Audio Output Level “low” decreases the voltage by around 4db as stated in the Lumin settings page or by 9.5db as you wrote above.
On this topic, can you also give some insight on how the Lumin max volume percentage relates to the output voltage. Does max volume 75% mean output voltage * 0.75 or is this something completely different?