DJM-750MK2 Tiny Buzz on Headphone Output

Just to inform I just opened the box and updated to the firmware 1.03, but I still get the buzz issue.

What headphones are you using?

Pioneer HDJ-X7

Are you hearing the buzz over music playing?

No, the buzz is inaudible when music is playing (since it is a low volume buzz). I read somewhere that maybe this buzz is caused by the headphone amplifier. I had other DJM mixers in the past (DJM-400, DJM-250, DJM-750, DJM-850), none of them had this issue. I just had an idea, I think I'm going to record this sound.

As I said, I did some tests yesterday. Here are my observations:
1- I couldn't manage to record the "buzz" sound, the volume was too low or the recorded "sound" was inconclusive
2- Using regular multimeter (the basic ones you find on stores), I managed to measure some voltage coming out from the headphone output, when the mixer is on. But again, inconclusive, the result was a bit "placebo"
3- This is the only concrete observation: no buzz is coming from the headphones when the mixer is OFF (obviously). After turning on you can hear a little "click". Then the display shows "Pioneer" then "v1.03". After that the buzz starts. Seems that the buzz starts when the mixer is ready to use (after initialization), such as a DAC converter or any other component. I have no idea.

Any thoughts?

I was just about to make a new post about this and then saw this recent thread recently started, glad to see I'm not the only one still.  I saw the original thread as well, and been talking with Pioneer tech support to get them to forward the issue to their engineers, praying it can be fixed with a firmware update.

I get the same problem and I've tried on TWO separate brand new DJM 750mk2 mixers now, I have them side by side to compare and the same audible little high pitched buzz/whine can be heard, more so in the right ear than the left ear, just with only the power plugged in and the mixer on, no other cables or anything plugged in, power plugged directly into wall socket and separated from any other electronics.

Nothing on the mixer seems effect the loudness of the buzz/whine, it is always constant, EXCEPT one thing and this may be crucial to the investigation of this issue, switching the EQ Curve switch from EQ to ISOLATOR will actually make the buzz/whine slightly louder, again more prominent in the right ear.

I am using Sennheiser HD 598's, they have an Impedance level of 50 ohms, in the previous thread the original poster said it only happened in certain headphones, leading to the belief of it having to do something with the difference in Impedance, so figured I'd include as much info as possible.

One other thing I forgot to add is that this little buzz/whine does not appear through any of the outputs of the mixer, it's purely isolated to the headphone jack for monitoring

I confirm that:
- On the right side the buzz is a bit higher (I'm using an HDJ-X7)
- Changing from EQ to ISOLATOR, changes the volume

I checked with my monitors (Pioneer Bulit5) connected via xlr on the master output, but there is always a bit of ground noise (maybe my cables arent the best).

some new info, i tried with a pair of Sennheiser CX150's which are some old earbuds I have.  The sound is much clearer, can hear a hiss as well behind the high pitched whine.  AND I discovered one other thing that effects the noise other than the eq curve switch.  For some reason the Sound Color FX buttons seems to slightly change how the buzz/whine sounds, particularly when switching back and forth between the Dub Echo and Sweep FX, Dub Echo makes the whine/buzz sound MUCH higher pitched, where the Sweep FX being on gives it a lower tone.  What's more interesting is that even when turning the effect off (pressing the button again that's flashing) the sound of the buzz/whine will not change, staying the same as whichever effect you last had activated, until you activate a different effect.

EDIT:  If this thread goes unnoticed again I will start a new topic with all the new info we've discovered on the issue to more easily bring the issue to light for the Pioneer engineers (tech support guy on the phone suggested I do this anyway to better grab their attention, more people report the issue, more likely they are to take a look at it and fix it)

Thanks for replying with another useless comment Pulse and then locking my thread where I gathered all of the current info on this issue

"All devices have a minimum noise floor on the various outputs, and there is an expected amount (albeit tiny) from lower-quality outputs such as the headphones. All I can suggest is you contact Pioneer DJ technical support in your region and they can inspect the mixer to see if it's within the norms of the headphone output."

You're being completely ignorant to the issue at hand.  Did you even read my post?  Or anybody elses for that matter about this issue?  First of all, the buzz/whine is not on the outputs, it's only on the headphone jack for monitoring.  Second, this buzz/whine does NOT happen on ANY of the other DJM mixers as people have already reported who were able to compare them side by side, even lower end mixers like the DJM 400 and so on (calling the 750mk2 a "lower quality" product is also ridiculous when it goes for $1200 flippin' dollars).  So it's not some "minimum noise floor" we're talking about.  This is an actual high pitched whine, reminds me of old TV's and it actually hurts my ears it's just loud enough and just high pitched enough.

I'm starting to wonder if it's an issue you guys introduced with the 1.03 firmware since originally people didn't seem to notice it when the 750mk2 first came out.  But after so many reports of this, ONLY about the 750mk2, with TONS of info that should tell you its not some "minimum noise floor" thing like how the loudness of the buzzing whine does NOT change with ANY volume adjustments, with NOTHING else plugged into the mixer, only power, and that it only starts AFTER it initializes and is ready to use, you should probably be taking a closer look at this instead of going around locking all the threads about it and being completely ignorant to the issue.

If this is the kind of support you guys have when you've clearly made a manufacturing error, then I'll be going with a different brand for my mixer, thanks.