Mix Outs: Noisy? (without Analog Filters) [IN PROGRESS]

Hi – has anyone else got noisy Main Mix outs? All my analogue filters are turned off (Effects menu) as I’m aware of the noise they introduce. My details are:

  1. I’m UK based so 240v

  2. I have no ground loops or any other noise-related issues in my studio

  3. I have tried 3 different power cables and power sockets

  4. Individual outs 1 to 8 are silent

  5. I have Mix Out knob turned to max

  6. Noise goes from:

  7. unplugged: silent

  8. S2400 plugged in but is turned off: -90db

  9. S2400 turned on / main Mix outs: -74db (noise increase of 14db!)

  10. S2400 turned on / Outs 1&2: silent

In the attached audio:

1 second: loud POP as S2400 is turned on then, you can hear the noise from main Mix outs
10 second: I quickly reconnect from main outs to the direct outs 1&2 where you can then hear the drop in noise.

Many thanks, Paul

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That is a feature! My Sp-1200 is a bit noisier still :laughing: All kidding aside, I will check mine when it returns from Isla HQ. Have you measured the noise level of the individual outs per chance?

The small amounnt of noise on each channel is summed into the stereo mix output.
As I’ve said in a previous post, I accept they are a bit noisey, but there isn’t much we can do about that.

A second revision of the audio board later down the line with the removal of the OG output filters, which will then allow the channels to be mixed into a stereo bus digitally will negate this, we can easily provide this as a crossgrade to existing users if they feel they can’t live with the noise. Since those filters are fixed frequency, they can easily be done in sofware with no noticeable (unless you’re a complete cork sniffer) difference in audio characteristics.
Hope that answers that.


Hi Brad - no cork sniffing going on with me :slight_smile: No worries about the noise; if I wanted “clean” I would buy Maschine…

The individual outs are super clean, even with the filters turned on. I’ll just use the Mix out for convenience then the individual outs for recording.

btw, I would be super miffed to lose the analogue filters. Sure, I know they have very limited practical use (Emu should have made the OG with HPF filters rather than LPFs). And, I know your machine is not a clone but to be super honest: I purchased a S2400 for only 3 reasons: 12bit, analogue filters, its a SP clone (I know you say its not a clone!!! :grinning:). I know that is a bit anorak but, maybe Im not alone my desire for the analogue filters tick-in-the-box, even with the noise on the Mix outs…??

You and you team have produced a gem, even with the noise…

Big thanks for some inspiration during these shitty times…

Paul, London


Sorry, missed this direct question. Yes, I have checked the individual outs both with and without the corresponding filters turned on/off. Filter On = very quiet and certainly quieter than all my other vintage stuff. Filter Off = pretty much silent…!!

So, its just the Mix out that is quite noisy, even with all the filters turned off. But as I said in another reply, its not a big deal. Sure, its probably too loud for recording or playing live but, because the indi outs are so quiet, there is an easy workaround…

thanks, Paul


with the addition of 8 SSI (SSM) filters on a card, it would far exceed the onboard fixed filters.


Damn Brad! Now I have to visit your website everyday to see when this filter daughter board will take shape. I will not ask “when” but please make this a future reality. Thanks!

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Since I doubt that all the filter chips out there are pin out compatible what I think would be dope is a universal filter daughter board that would accept various filter chip cards, a’ la Studio Electronics Omega…


Bingo… :slight_smile: That is what I was going to say with daughter card options this becomes a moot point… (a mute point in this case… j/k)


Is the headphone out also noisy with the filters off?

(Audio interface shopping and trying to figure some things out)


When the SSI (SSM) filter card comes into existence, can the card additionally have room for a gain stage/boost for each of the 8 channels as the independent outs are not quite hot enough currently? Just asking. Tnx!


yes, some kind of pre filter drive would be sweet, push the pressure


This could be really cool.

I love the sound of CEM filters. One of the reasons that I keep an old Sequential Circuits Studio 440 kicking around. The 440 which uses a CEM 3389 for each voice, just sounds so nice to my ears. Love the SSM2044 filter chips in my SP 7030, but to my ear the CEM 3389 sounds smoother and more buttery. Has a certain oozy warmth when filtering samples and adjusting the VCAs.


I forgot to link to this in my last post:
Here is the CEM 3389 Data Sheet for nerds.

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I believe almost all of the users here are just waiting for a release date on filter daughter board.

No pressure.


Not sure I’m following, what do you mean by this?
Will a new audio board make playback of more than 1 track per output possible? Or what will the digital mixing bus do?

I’m confused since the outputs as of now can also play the live-loops and input monitoring on an occupied put.

Yes the playback through 8 outputs will still be possible it just means that but the summed stereo will not include the noise that is introduced by the OG output filters from each channel into the strereo mix out since they will no longer be there.

get a USB isolator.


Hi Paul,
Was this noise issue ever resolved? I’m asking because I’m experiencing the same noise except on all outputs, main and individual. Headphone out is fine. Let me know! Thx

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