The missing / additional parts may not (probably don't) mean anything. Sometimes when a circuit is designed, extra component footprints are included in anticipation of possible future design modifications. It's easier and cheaper to say "do not populate" on a bill-of-materials than it is to redo the layout of a PCB.

I'm not saying that this particular PSU isn't failure-prone -- I think its track record speaks for itself there -- but it likely has nothing to do with the presence or absence of those parts, and more to do with the use of cheap electrolytic caps in the DC output filter.

Is there a way to just deactivate the USB part? I love the sound of this mixer and pretty much never use the audio interface portion, but the 8k whine just makes it unusable for recording.

I have severe 8 and 16 kHz spikes on my 22MTK but only when the mixer is connected to pc via usb. When I disconnect the usb-cable the spikes disappear. Do you have the 8 kHz even when you have no usb connection?

If you want to completely deactivate the usb part, you can just open the mixer and disconnect the power supply cable from the usb port. It's a quick and easy fix (ok, maybe not so quick because you have to remove a lot of screws to access the inside, but then you have direct access to the board and then you just pull the power connector from it and you hang it to a safe place with some tape or hot glue) and it's also a completely reversible mod (just re-connect the power connector).
The noise floor on the main out is lowered after this mod (but it's still slightly noisier than the groups).

I actually did this mod on my Signature 22 MTK last summer.

I even thought to repurpose the usb buttons as insert buttons or monitor buttons, I think I would have to replace the usb board with a board full of buffers, but I didn't go as far as tracing the connections and designing the board (I'm not trained in electronics, so it's not a quick and easy task for me and I thought that I can live without this feature...).

Hi, Just wondering... How old is your 22MTK?

Did Soundcraft ever fix the (spikes) problem in newer production runs?

I'm asking because I'm thinking of buying a 22MTK (new)...

Much thanks for any advice.

I bought my 22MTK in may 2018.
I haven't heard that Soundcraft should have fixet the problem in newer production. But there has been posts on the web telling that Soundcraft service people have informed customers, that they could not solve the problem. They said, that you just have to live with the problem. I think there might be many MTK's that have the spikes in the same degree as mine, without their owners are aware of it, because they haven't payed it attention. Normally I only use my 22MTK for multitracking and never listen to the master out after recording. (I mix on a Si Impact). But when I a year ago recorded a choir and played the master track back on PA-loudspeakers to the choir on location, I heard the 8 kHz spike clearly. (Not the 16 kHz as my ears are 71 years old)
My advice is, that if you buy the 22mtk be sure to make some tests at once and go back to your dealer, if the spikes are a problem.

Good advice - Thanks very much.

Hi everyone, I desperately need some help here... is there any way to use headphone monitoring on a 22 MTK with the speakers muted?? I just can't seem to do it. I am trying to monitor the output from Logic whilst recording vocals etc, but when I mute the speakers, I lose the headphones too. Unmute the speakers and the headphone output comes back, mute them and it's gone again.
I've tried toggling the USB RTN for the computer output, if it's off I obviously don't hear anything, if it's on it doesn't matter if I try to mute the speakers because it keeps 21/22 live for intervals. Tried changing the output from Logic to 19/20, same thing - can hear through speakers and headphones unmuted, neither muted.
This is crucial for me to be able to record in my studio so if this isn't possible I may have to return the mixer! Is there a way round this?!

I should say that I've tried routing the Logic output via aux busses and plugged them into a headphone box, but everything comes out one legged. I've used both a mono and stereo quarter inch cable but it's the same with both. Tried plugging the headphone direct into the aux outs too, all one legged. Am I doing something really stupid??

I just picked up a MTK 22. Is it just my unit, or do these mixers forget their FX settings when they're powered down (or 'unplugged' may be more accurate since they have no on/off switch)

Are you using the 'interval mute' mate? That's not a master mute, that mute's 1-20. You're missing a few fundamentals here I think. You cannot mute the master out. Where you're looking to lower the volume of your monitors, you employ a monitor controller. Your master fader is not a volume control, it controls the level of input 23/24. USB RTN only changes the channel from an input to an output. More help on FB in the SignatureMTK Users Group

Like an electronic circuit... if you cut the power, it resets.

Thanks! Just wanted to make sure I didn't get a lemon. ...rather uncommon for a piece of modern gear not to retain it's patches though.

I have a Soundcraft 12 MTK and find it excellent so far, no issues to date.

However, one limitation I am finding is that I now have two outboard stereo effects units that I want to use simultaneously.

Both are stereo in/stereo out effects units, but can be used as mono in / stereo out, and that is how I am having to use them because the MTK 12 only has three aux channels, one of which appears to be dedicated the on-board effects.

I really want to use both effects units as stereo in / stereo out, so I am considering buying a 22 MTK, as this has five aux channels, so I thought I could use four aux channels as two stereo pair sends, leaving the remaining aux for the on-board effects.

However, checking the manual, the 22 MTK has two on-board effects that use aux 4 and aux 5.

Can an owner of a 22 MTK please let me know if I can do what I want to achieve by using aux 4 as the right-side channel (along with aux 3 as the left channel) with my second effects unit, or is aux 4 hard-wired to the on-board effects#1, meaning I cannot use it how I intend?

I use stereo mixer channels for the returns from the effects units.

Thanks,
Steve

Sorry, to put my question on this place. You seem to be someone who knows his Signature 12 MTK and I can't find out how to make a new Thread (searching and searching but there just isn't a button New Thread on my site)

I am running out of inputs and since the Brochure states the Sign 12 MTK is 14 in 12 out I figure I could use input 11-12 AT THE SAME TIME as routing back the computer audio (via USB). But I can't find out how. Do you have any idea?

Help would be much appreciated.

I'm not an expert on the Signature 12 MTK by any means, but I am successfully using channels 11 & 12 at the same time as bringing the Master audio back to my PC (running Ableton) via USB on channels 13 & 14, which are dedicated to the Master Return.

Make sure you have the USB Return button deselected (pressed out) on Channels 11 & 12 and use the phono inputs at the top of the mixer adjacent to the USB socket.

I was also able to record the audio on channels 11 & 12 back to the PC and play that recorded channel audio back out to channels 11 & 12 with the USB Return button selected (pressed in).

Cheers,
Steve

hello everyone

i need soundcraft signature 22 schematic daigram please help me

Hello,

Long thread...thought of posting here instead of starting a new one.

Looking into the 22MTK. I like the one knob compressor on my xenyx mixer though, and the MTK has limiters but not compressors. Can this limiter emulate a one-knob compressor in any way? Maybe by driving the gain of the channel and engaging the limiter? Anyone with experience with both could chime in?

It is mainly for drums from an analog drum machine: kick, snare, hihats, and maybe a synth...Thanks.

From my understanding, having read all of this thread, is that it is very much a limiter and does not carry out compression of any kind.

From what others have said previously, it also seems quite hard to push the levels hard enough that the limiter kicks in. I've run some hot signals into mine and never had the limiter activate on my 12MTK.

From the lack of activity on this thread, i'm late to the party with my purchase of the 12MTK, but I think it is great.

Cheers,
Steve

Thanks for your reply! Yes, I have put in my mind that they are definitely not the same thing (xenyx compressors and soundcraft limiters).

What I don't like in the xenyx mixers is the fx and aux pots. They are hard and small, crammed together, so not easy to twist them for live/dub style jams.

I am looking for a higher-end (soundcraft, etc.) analog mixer alternative to the Behringer Xenyx QX2442USB but there seems to be none unfortunately...I'm looking for a mixer with:

- Direct post-fader outputs (15 in total - these don't have to be channel direct outs exclusively, but can be rooted through the subgroups, auxes, etc., like with the Xenyx 2442 which has only 8 direct outs but s2 stereo subgroup routings + mono aux send)
- one-knob compressors in at least 4 channels
- at least 2 post-fader aux sends
- ideally an onboard good quality fx processor

It does not have to have USB interface (I use separate ausb audio interface) but that would be a bonus. As you can see the Behringer Xenyx QX2442USB has all of these, but I don't see any other (better quality maybe) analog mixer which ticks all of these boxes. I looked at current mackie, soundcraft, allen and heath and the new korg mixers but they may have some of these characteristics - like direct outs - but not others, like compressors in the channels.

Any suggestions welcomed.

I have a question regarding the "Ghost Mic Pre-amps". Are these connected to the XLR inputs only, or to the XLR AND the 1/4" input?

I would like to try sending a 909 kick drum from a drum machine individual out into a 1/4" mixer channel in the line input and try overdriving that with the pre-amp but if the 1/4" does not run through the pre-amp, this will not work how I expect.

Thanks,
Steve

I Have The Same Problem Has anyone been able to help you?

Hello all
Just saw this thread was still going. Getting frustrated.
Am a blind musician, bought MTK 12 last year because of a complete physical layout other blind users put together.
Trying to play along with a backing track and record a simple stereo mixdown post fader through USB channels 13/14. Listening through a set of older Creative Labs media speakers connected to master out. I also have good headphones, everything sounds fine.
Using Reaper. Playback is set to 11/12. Backing track loaded to track 1. Audio track for my wind controller Recording set to 13/14 on track 2, controller plugged in to 7/8.
First, backing track does not play back unless USB return on 11/12 is down. Set everything to balanced levels with gain/faders.
Second, recording does work but at a very very very low signal. Using USB cable that came with MTK. My talking screen reader can read the meters and I am getting DB in the -20's if not lower.
Adjusting volume up close to the levels set earlier using Reaper keyboard commands produces clipping no matter what I do, adding some compression fixes somewhat.
When soloing the recorded track, the backing track is bleeding through very quietly because of the 11/12 USB return being down. But that is the only way I can get playback? Shouldn't 11/12 not require USB return to be down? I can't get much out of the manual but it did seem to say that 11/12 were dedicated playback channels?
I am sure I'm in the minority here but all I want is to record post, at exactly or close to the levels I set with channel gain/faders and master fader. I don't mind messing with volume/FX afterwards but what is being recorded is so quiet it's almost unuseable.
MTK is functioning fine, just can't figure what I am doing wrong. As a last resort, might pick up a 2X2 interface and run MTK through that.
Any assistance is greatly appreciated.
Thanks.

Hi guys,

I've made a new thread about it, but as of yesterday it looks like my Soundcraft 12 MTK has a broken fader in the "Group 1-2" outputs. I've been using these outputs to drive my left and right monitors, but now all of the sudden the right fader has no effect and just plays whatever channel I route to it at max volume! The first fader in Group 1-2 seems to be entirely unaffected.

I'm wondering if this is a hardware problem that anyone else has had, or if I just got a bad unit? Even though it's been working great for a couple months since I got it.

Soundcraft Signature 12 MTK master fader broken?

I'm working with a new Signature 12. In testing all the inputs/outputs, I noticed that the XLR microphone inputs on the two stereo channels (7/8 and 9/10) are a good deal hotter than the others; you have to keep the gain at least 5dB lower to get the same results. I've tried this with a condenser/phantom power on and a dynamic/phantom off; same effect.

I know that these are potentially stereo channels, but the instructions say that they are mono when using XLR, so I don't see why that would make any difference. The specifications aren't very specific, but I don't see anything different about those channels.

I don't have this problem with the 1/4 inch plugs on those channels. If anything, they're a pinch quieter than the others.

Are all the units like this or am I working with a defective one?

Hi Everyone,

Having some troubles with white noise and my set-up using the MTK 22. I'm running MTK 22 --> Mogami Gold Balanced XLR --> Adam Audio Sub 8 --> Cordial Peak XLR --> Focal SM9's. Removing the Sub from the chain results in the same issue outlined below.

Even with all the faders completely down on the MTK 22, I'm getting a solid amount of white noise through the Focals. With nothing running through the desk, pushing the master volume increases the amount of white noise through the monitors. Past +0 dB on the master fader, and the white noise becomes resonant.

The moment I take the XLR out of the MTK 22, the white noise stops. So I'm inclined to think that it's the MTK 22 causing the issue.

Has anyone else had similar problems? Any suggestions at working through the problem?

Many many thanks,

Amphib

I received a response from Harman support (pretty quickly, I might add). They said:

"I spent the morning recreating this and it looks like it has to do with how the stereo channels are summed together. I took the test a bit further by panning the channel hard left (I did this with both channel 1 & channel 7/8). There's an increase on any channel when doing that as well. There's no difference in preamp type, just whether their mono or stereo..

The only way around this is the reduce the preamp gain, as you discovered."

I've had my 22MTK for about a year and a half. It's powered on 24/7, and I've never had a problem with it. Today I went to open my DAW and realized that I no longer had any audio devices showing. Worse, Windows wasn't even able to start the Audio Driver. Looking at the device manager, I could see that something was connecting and disconnecting rapidly - but it was happening too fast to figure out what. I unplugged the 22MTK from USB, and it fixed the problem with Windows.

At that point, looking at the mixer, I realized that the phantom power was turned on. I have always been paranoid about the power supply issues on this mixer from reading about others' problems with it, so I only turn the phantom power on when I actually need it. This time, it had been on, powering a connected microphone - for about two weeks or so.

Figuring it was the PSU issue with the electrolytics talked about here, I took my 22MTK apart and pulled the PSU. Neither of the capacitors were bulging:

arghh this site won't let me embed images, but here is my picture of my capacitors:

https://nerocam.com/images/22MTK_Capacitors.jpg

I desoldered the two capacitors and measured them. They are 100uF capacitors. One of them measured 71uF, the other one measured 39uF. Not good.

I had on hand some 100uF, 35v electrolytics, so I soldered them in place. Put it all back together, powered up, and it's good as new.

I'm pretty disappointed in Soundcraft that there is clearly a design issue with the PSU that has been going on for YEARS, and yet they have not addressed it. I bought my 22MTK brand new in March of 2020.

I had the same problem, it was ground loop noise between the PC and the mixer. I used one of these USB ground loop isolators and it fixed the problem:

https://amzn.to/3kggjbj