MOD Duo background noise level


#21

we would have to define “long”. it sure is not on the next software release.

because we are talking about the Linux Kernel, the matter gets tricky.

On one side there are people around the world working on it. We could simply “wait”

On the other, we could put resources to accelerate, but that costs money and we need to develop the business a bit more .


#22

Hi @AndyCap

Some computers leak A LOT of noise via USB. I have a desktop that makes even my Mackie Onyx get noisy.

Is your a desktop or a laptop?

Did you try changing the USB port?

In case of laptops, try with or without the AC charger ?

Last, but not least, ever tried a USB hub?

Sorry for the many questions. We surely have filters to isolate the USB, but filters have a limited performance.

If we were to have a device with the USB connection “totally isolated to the point that it would be invulnerable to external noise” the costs would be prohibitive.

And in this case, it is easier to work on the device that is actually sending the noise (the computer/laptop, in your case)


#23

Hi Gianfranco,

It’s a MacPro trash can.

I have lots and lots of musical gear connected via USB and the only one I get noise with is the Mod.

I have tried different leads, direct connection and via hub.

The noise is of a level where connection via USB is not useable.

Cheers

Andy


#24

Just ordered a USB isolator, I’ll let you know how it goes…


#26

@AndyCap I’m interested in how it works for you.

I don’t have any noise issues with the Duo. However I have other gear that has caused havoc on my setup and often wondered about using an isolator. Just never pulled the trigger to get one.


#27

I got the Isolator and plugged it in.

An amazing difference, silence at last.

Here is the before audio: https://soundcloud.com/bobthedog/mod-duo-usb-noise

And the After audio: https://soundcloud.com/bobthedog/mod-duo-isolated

This is the isolator I am using: https://www.amazon.co.uk/gp/product/B00M1QQBJ0/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Worth every penny!


#28

Hello @gianfranco

I hope you are doing well.

Did I miss something or is this issue still there ? I tried a bit of microphone recording over my holidays and the results were not great at all, even when using input 2 (but I have not played much with the different workarounds your are listing here)

What is the difference in terms of hardware between the Gain stage and the Fine Gain ? How would you typically adjust things including the internal volumes of the pedalboard pluggins ?

Thanks in advance,

EDIT: @falkTX would you have any fresh info on the question of switching to the mainline kernel ? Cheers to keep us posted !


#29

Hi!

I have recently bought the Mod Duo and I love the idea of it.
Unfortunately I also struggle with background noise… A high frequent buzz.
Does not change with usb plugged or unplugged. It changes frequency when I change buffer size.

Hope this problem will be solved soon.


#30

Hi everyone,

Any progress on this topic ?

Azza


#31

…i haven’t heard anything, and the noise hasn’t changed in the latest upgrades.


#32

I asked that very same question during one of the live sessions a year ago, and I got the answer that work was being done to fix it, but I don’t know if anything happened since…

Anyway I got (somewhat) around the problem by using headphones out only with Y-cable going to my amps effect return. I stopped using the normal outputs completely.

Not really a perfect solution, I know…
but it’s ok while waiting for a proper fix.


#33

Hi @broupe,

I’m sorry, but I don’t really understand how your solution addresses the problem. Could you post a bit more detailed description ?

Thanks in advance,

Alex


#34

The output noise that bothers me is not quite as loud in the headphones output; therefore I am using that.


#35

Hello @gianfranco

Is there any news regarding this noise issue?

Rogério


#36

hey @rogeriocouto … do you know about the hardware modification that the MOD team will do to help with this issue? i sent my DUO back to have it done. the noise is certainly reduced - enough that i no longer feel the need to use an analog noise gate after the MOD outputs in a lot of situations. however, it’s only ~reduced~ – i.e. i don’t believe the root problem of kernel buffering has been solved.

i asked @dwek about this, with respect to the new DUO X, but he hasn’t replied specifically about that concern.

yes, i agree that it’s a fundamental issue that needs to get solved – so thanks for chiming in! :slight_smile:

i’m hoping that the increased CPU power in the X and in the planned DUO processor upgrade will allow kernel patching which solves this, but haven’t heard about any specific plans.


#37

Hello @plutek,

Sending the DUO back to Germany is not an option for me.
I don´t think a noise gate as a good solution because the noise is a very specific frequency (F#) and will be present when the gate is open.
The major problem here is that this reduces the Headroom of the DUO specially if you play softer.
This recently became an issue to me because I´ve changed my guitar amp and now I can here it.
Also I get bored of playing C Lydian forever!!!:wink:
Cheers


#38

yes, @rogeriocouto… you’re right that it is a pitched noise, and thus quite perceptible. :frowning: in my usage, careful gain staging plus the hardware fix is usually enough to make it ok enough. also in my use case (only after the hardware fix), the noise is virtually imperceptible under the signal when i use a noise gate.

one thing i have noticed is that it’s somewhat less objectionable when it’s dropped an octave, by switching the buffers to 256 - and the latency is ok for me.

but, yeah, having it really fixed eventually will be a big relief!


#39

Indeed… the 256 buffer size make it less noticeable. I will see if that buffer size is ok to work with.

Thanks


#40

I’ve done the hardware mod at home following instructions provided by the mod guys.

It basically consists in replacing a capacitor and an inductance for ones with larger values.

I didn’t have the correct tools for this (the components are surface mounted (SMD) which ideally requires a hot air gun) so went into a scary moment, where I ended up tearing up a bit of the copper from the board (!!!) , but eventually managed to save the situation. The noise is indeed reduced now.