I got my quantum 2626 today and was testing it out and was having some issues.

I’m connecting the quantum 2626 to a new MacBook Pro M1 pro via an apple thunderbolt 3 cable. The cable is a known good cable from my HDX system.

When the interface is powered up and connected to the laptop with the TB3 cable an electrical feedback/static noise is coming from the Quantum’s outputs and headphone jacks. If I plug the power supply into the laptop the noise stops. Noise is similar to a cellphone next to a speaker.

I tried plugging the quantum directly into a power outlet and also tried it on different power outlets with different power conditioners (furman) with no change.

Quantum is up to date with the firmware.

Only thing that solves the noise issue is plugging the laptop in to the charger.

Is it an issue with the quantum?

Any help would be appreciated. Thanks

I also have a MacBook Pro and a 2626 (actually have both that and a 4848). I can't say I've ever run them without the laptop charger plugged in. I can try this weekend and see if I get the same issue.

It sounds like an electrical ground issue to me.

Ya its strange for sure. Sounds like a cellphone by a speaker type of EMI noise/feedback.

Tried different outlets and different power conditioners, didn't help.

Also without your MacBook charger plugged in, does it say the 2626 is charging your MacBook?

I've been super busy with the day job, I'll let you know as soon as I can actually get up there to check

did you manage to fix this?

Yes, but not sure what fixed it. Swapped outlets and surge protectors, and cables etc. to no avail.

Then I tried an apple tb2 cable with an tb2 to tb3 adapter on both ends and problem solved. But to my surprise, when I tried the original cable that was giving me issues, that was now fine as well.

Didn’t make any sense, still doesn’t, but it’s fixed so I’m not asking any more questions haha.

i cannot find any similar threads and this is the closest thing to what i experience with my quantum2626 so i figured i would drop this in here and see if anyone has had a similar problem.

if i leave a session open for long enough, the quantum inputs will start generating a strange electrical interference type of noise, and disabling/reenabling coreaudio/the interface itself in my DAW does not fix it. i have to shut the DAW down completely and reopen for it to go away. ive narrowed it down to the interface's inputs because disabling monitoring on any of the active ones will silence the noise when it is happening.

this only happens after a session has been open for many hours, otherwise the interface is dead quiet. has anyone experienced a similar issue to mine?

just to be thorough, im running macOS 10.14.6 and Ableton 10. i have not tried to replicate it in my copy of ProTools One but i suspect the same thing would happen after long enough.

I would disconnect all the input cables when the noise starts, then I will check which input actually generate noise after disconnecting all the input cable. It can be unit itself or the cable. Can also be PSU noise.

ive done this, they all do it with nothing plugged in when the issue is present

if it were PSU noise then why would it go away when disabling inputs? wouldnt it be present on the output directly from the interface regardless? also wouldnt it be constantly present as opposed to intermittent? it isnt 60 cycle noise, its like a strange digital sounding interference kind of thing. next time it happens i will record it and post it here.

If the noise is coming from a specific input, then it is highly likely that there is an issue with the analog section of that input, as the digital portion and the PSU are shared.

The PSU is an SMPS, so we would not really expect 60Hz hum when PSU is dying. It can be a ground loop, a PSU issue, software issue, or the unit itself.

Posting the noise is a good idea.

all the inputs do it, it isnt limited to a specific input when it happens.

thats interesting information, thanks. yes i will post the noise as soon as it crops up again.

thanks for your help.

an update:

it happened again, and i realized i was misremembering/explaining the part about "disabling inputs" incorrectly and/or in a less than succinct way. it doesn't go away when disabling inputs per se, it goes away when i disable the device as the 'audio out device' in ableton. it doesnt go away if i disable it only as the 'audio in device' though. turning off inputs via 'Ext. In' does not affect the sound.

i attempted to record it and it does not appear on recorded audio. it is only appearing on the audio output itself. however, the sound fluctuates in pitch and timbre when starting and stopping playback. the most similar noise i can think of is when you pick up interference from a digital device on a CB radio or the sound that occurs when certain cranked guitar amplifiers pick up interference from a cell phone being on top of them when nothing is being played through them. in the moment, i didnt think to try and get a recording of the monitors with my phone, and so ive already restarted the daw which fixes the issue when it occurs.

i figured this new information could be helpful in making an assessment as to what it could be, so i thought it was good to give a quick update here. next time it happens i will try to get a recording of the monitor output with my phone.

I have the same problem, and it happens to me both on a Macbook Pro in a certain set of circumstances, and it seems to be ever-present on a new PC that I built, regardless of what I do.

What I found was that on the Macbook Pro, if I was using the USB-C Digital AV Multiport Adapter and using an HDMI display with the power adapter plugged in, the noise would be there, but if I unplugged the power adapter, the noise went away. If I unplugged the USB-C Digital AV Multiport Adapter and plugged in the power adapter by itself using only the laptop display, it was fine.

On the PC, it's just there, all the time.

It's a really harsh high frequency noise that is not captured with the input signal, however it makes its way into output signal on the analog line outputs, or headphone outs - so when monitoring anything, it's there. It sounds like a digital signal.

I've tried all kinds of different Thunderbolt cables (Short, longer, TB3/TB4), no change.

I've had this experience since day 1 with this interface, and I really regret not returning it to Amazon. It hasn't been worth the trouble. I wish I didn't sell my old one :(

This tend to happen when one of the thunderbolt connections negotiates power delivery.

For example, a MacBook connected a Studio Display that negotiates pd to the laptop, will start generating GUI movement fuzz and buzz noise on all the line outputs of a thunderbolt audio interface. The noise is at a constant level that doesn’t change with gain and never seems to show up on headphone outputs. Not sure what that tells us.

The secret, which I think you figured out, is to first connect your MacBook via MagSafe port to a high wattage charger, so that no thunderbolt connections that you make can negotiate a higher wattage power delivery and introduce the noise.

Studio Display for example can deliver 96 watts to your laptop, so use need to use a laptop charger at 140 watts to win the pd negotiations.

That’s the goal for any tb audio interface system I think, take control of pd negotiation and avoid it if possible.