• Registered: 2023-02-17
  • Posts: 3

Topic: Loud hum in 1 channel and volume needs to be very high to hear music

Hello, I really hope someone can help. My ADI DAC 2 worked perfectly last year. I've had it in storage since then and just connected it again (to a different amp than before) but now it makes a loud hum in one channel when no music is playing. When I do play music I have to turn the volume right up to -10db to hear anything. There is little difference when I change the Reference level from -5db to +1db, +7db and +13db, even if I select Auto Ref level, the same 2 issues persist.

I'm currently playing music to a Bluetooth receiver that is connected to the ADI-2 via Optical. The ADI-2 is connected via RCA to a Denon RCD-M40Dab (it's an integrated mini system/receiver).

To try to isolate the problem, I've tested with the Bluetooth receiver connected directly into the Denon both via RCA (using the Bluetooth's cheap integrated DAC) and via Optical (into the Denon's integrated DAC). Both tests work fine. There is no humming and the volume levels are what I would expect. I only get the humming and the need to turn the volume nearly to max when putting audio through the DAC.

I would be very grateful for any help on this. Thank you.

Sonore ultraRendu > RME ADI-2 DAC> Denon RCDM40 > Monitor Audio Monitor Nine

2 Reply by MC

  • MC
  • MC
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Re: Loud hum in 1 channel and volume needs to be very high to hear music

Same hum in the other channel when you swap the cables at the back of the unit?

Did the other amp use XLR?

Regards
Matthias Carstens
RME

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3 Reply by chris.letteriello (edited by chris.letteriello 2023-03-05 21:50:06)

  • Registered: 2023-02-17
  • Posts: 3

Re: Loud hum in 1 channel and volume needs to be very high to hear music

MC wrote:

Same hum in the other channel when you swap the cables at the back of the unit?

Did the other amp use XLR?

Thank you for your reply and apologies for taking a while to answer your question. I wanted to have a good listen with some method so I can describe better the issue that I’m getting which is that I’m getting a crackling/fuzzy sound (not humming) in the left channel. I did swap the speaker cables around and the RCA cables and each time the crackling occurred in the right channel instead of the left. The last amp I used (when everything worked fine) was also via RCA.

I’m using the ADI-2 DAC FS solely as a DAC with its volume set at 0 db, and without B/T or EQ.

When I listen to a track direct into my receiver/amp (via RCA, optical or USB), I do not hear any fuzz/crackle in between tracks or when the music is not playing, at any volume level. At 30-40% volume for normal listening (depending on RCA, USB or Optical input), at around 50-60% for louder listening or even at 80% there is no fuzz/crackle at all.

When playing the same track through my ADI-2 into my receiver/amp’s RCA at the same volumes I get fuzz/crackle noise: at 30% volume it’s audible at 1 meter from the speakers and I can sometimes hear it during quieter passages of play also; at 50-60% it's louder, audible at 2-3 meters and also more commonly heard during quiet passages. I have 2 sources connected to the ADI-2, a renderer (Sonore ultraRendu) via USB, and a BT receiver through optical. Both sources give the noise described when going through the DAC.

I have to say though that the ADI-2 and Sonore together sound wonderful! I’m going to upgrade my amp so that I can enjoy them both even more, but I would like firstly to eliminate this fuzz sound. I appreciate your help.

Many thanks

Sonore ultraRendu > RME ADI-2 DAC> Denon RCDM40 > Monitor Audio Monitor Nine

4 Reply by KaiS (edited by KaiS 2023-03-06 07:12:49)

  • KaiS
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Re: Loud hum in 1 channel and volume needs to be very high to hear music

The noise as you described it is typical for contacting problems, like connectors or switches of analog controls that do not make good contact.


To nail the problem switching cables left/right, ONLY at ADI-2’s out, would eliminate or confirm it’s an ADI-2 problem:

• If the noise moves to the other speaker, it’s ADI-2.
• If the noise now is on the same speaker, the problem is further down the chain.

• Same way you can trace the problem with cables, connectors, amp etc., one at a time.

KaiS's Website

5 Reply by chris.letteriello (edited by chris.letteriello 2023-03-06 19:07:02)

  • Registered: 2023-02-17
  • Posts: 3

Re: Loud hum in 1 channel and volume needs to be very high to hear music

KaiS wrote:

The noise as you described it is typical for contacting problems, like connectors or switches of analog controls that do not make good contact.


To nail the problem switching cables left/right, ONLY at ADI-2’s out, would eliminate or confirm it’s an ADI-2 problem:

• If the noise moves to the other speaker, it’s ADI-2.
• If the noise now is on the same speaker, the problem is further down the chain.

• Same way you can trace the problem with cables, connectors, amp etc., one at a time.

Hello KaiS,

Thank you for your help. I have changed the RCA around and the noise moved to the other speaker, so it looks like the problem may be the ADI-2. It worked without this issue until March last year (2022). I kept it packed away in storage for a year and now that I have connected it again I have the issue.

Does anyone know how I can get it repaired? Do I have to go to an authorised dealer?

Many thanks,
Chris

Sonore ultraRendu > RME ADI-2 DAC> Denon RCDM40 > Monitor Audio Monitor Nine