Lumin U2 – Sudden and drastic volume level increase using Leedh Processing

Audio Gear Talk Lumin
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Hello LUMIN Support Team,

I am reaching out regarding a sudden and significant change in the output volume behavior of my Lumin U2 digital transport, which occurred exactly two days ago without any physical changes to my audio system configuration.

My System Architecture:

  • Source: LUMIN U2 (connected via LAN-to-Optical LHY converter, powered by Lampizator Kraftwerk 10 power station).

  • DAC: Lampizator Big7 (with PX4 tubes).

  • Preamp: Audio Note M6 Line (stepped attenuator / high-gain architecture).

  • Power Amps: Audio Note Conquest Silver Signature monoblocks (300B tubes).

  • Speakers: Audio Note AN-E SPe HE (connected to 8-ohm taps).

  • All power and signal cables are premium silver Kondo.

The Problem:

My usual listening configuration to achieve a peak volume of 90 dB in my room has always been: Preamp at the 4th step (stepped attenuator) and LUMIN U2 volume at 60% using Leedh Processing.

Two days ago, the volume suddenly jumped drastically. Now, to maintain the exact same peak of 90 dB at the same 4th step on my Audio Note preamp, I am forced to lower the LUMIN U2 volume slider all the way down from 60% to 40%.

Furthermore, at this new 40% Leedh level, the sound has become “nervous,” sterile, and lacks the organic analogue micro-dynamics and weight it previously had.

What I have already verified and done:

  1. Hardware Factory Reset: I have already performed a full physical Factory Reset using the reset button on the back panel of the LUMIN U2, but the problem persists.

  2. LUMIN Settings: General “Volume Control” is ON, and “Leedh Processing” is ON.

  3. Volume Levelling: The “Volume Levelling” (ReplayGain metadata feature) is strictly set to OFF. I tried toggling it on and off, but the excessive volume output remains.

  4. Tidal Settings: Inside the LUMIN App, “Tidal Connect” is set to OFF, and I play music natively through the LUMIN App.

  5. Hardware: There are no gain adjustments or hardware changes on either the Lampizator DAC or the Audio Note M6 preamp.

Could you please verify if a recent automatic firmware update, a hidden gain offset, or a change in how Tidal streams are currently processed in the background could have caused this sudden ~10 dB volume spike?

Lowering the Leedh volume to 40% is pushing my system to the very edge of the truncation-free threshold, and it is degrading the synergy of my high-end tube and silver cable system.

Thank you in advance for your expert guidance.

Best regards,

Krzysztof

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This isn’t the official Lumin support although you may receive a response regarding firmware. The official support is:-

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Thank you for the heads-up regarding the official support channel.

Yes, I am aware of it, but I am intentionally looking for insights and potential solutions from various expert sources to fully understand how my hybrid digital/analogue setup behaves under these specific conditions.

I would still highly appreciate any thoughts, feedback, or suggestions from the community or the LUMIN team regarding firmware changes or hidden gain behaviors. I want to keep this thread open to gather as much technical information as possible.

Best regards,

Krzysztof

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Already replied to your e-mail.

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Update: the OP has fixed this issue.

We’ve experimented firmwares, setting changes, and it was suspected a new tube in his preamp may have contributed to the issue.

No other user reported a similar volume issue, regardless of volume-related settings.

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