Help understanding the Inputs

Hi all,

If anybody has the time and inclination, would they mind explaining to me once and for all how the inputs work, how they differ, for what purpose they were designed, to what preamps / filters they are routed to etc.

I know this is covered in various sources but it would help to have it summed up in one go!

The manual states:

K. Input 1 & 2: Two ¼" mono jacks for sampling input. Connected to a preamp.

L. Input 3 & 4: Two ¼" mono jacks for sampling input. Connected to a preamp. Input 3&4 are
normalized to Phono1 so you can connect RCA plugs, but still go through the preamp.

M. Phono 1: A pair of phono jacks for sampling turntables. Connected to RIAA preamps.

N. Phono 2: A pair of phono jacks for sampling turntables. Connected to RIAA preamps.


Input 1 & 2 routed through an anti aliasing filter, a preamp, or both? What type of preamp / filter?

Input 3 & 4 are normalized through phono 1, why? To utilise the preamps?

Phono 1 / 2, what are RIAA preamps? why would you route phono 1 through Input 3 & 4 to use the other preamps?

Those are the main things that spring to mind, but if anyone feels up to the challenge of explaining each input it would be greatly appreciated.

Peace, Prosperity, Love and Music to you all!


I can’t answer all of your questions, but I can tell you that RIAA preamps are specifically for phono signals. The signal from a turntable must be amplified by an RIAA stage to sound proper. So, the RIAA preamps are just that, phono preamps and nothing more. I don’t recall the exact “routing phono 1 through input 3&4” part (I know what you mean, I’m just not sure about the correctness), but what that is referring to is that on the back of the S2400 there is a trim knob for the preamp. So the signal goes through the RIAA circuit and then through the actual “preamp” for more volume, if needed. Hopefully that helps. I cannot explaing anything about anti aliasing or filters.

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Thanks for the RIAA info, that’s one piece of the puzzle solved. It was the fact that when you run something through phono 1 it is picked up on 3&4 which got me curious about the input structure in the first place.

Thanks again for the help :+1:

Inputs 3&4 are normalized to phono1. That is so that you can plug a common 3.5mm to RCA cable into phono1, and sample from inputs 3&4, bypassing phono1’s RIAA filter.


It’s clicked with me now. So it’s basically a function to allow flexibility between inputs. Thanks

Yes, to reinforce what Mickey said and make my point clearer; turntables output a weird signal. Think of it like it is muffled or not equalized properly. The RIAA preamp corrects this “weird” signal to what we would want to actually hear. If you were to plug a synthesizer with RCA output jacks into the phono input and it went through the RIAA preamp (without needing to), then it would sound different than expected. So, you could connect it to Phono 1 and then sample from Line 3/4 (assuming nothing is plugged into Line 3/4) to get the correct sound from that “non-turntable” device. Or lets say you wanted to use a DJ mixer between the turntable and S2400. Sampling through the Line 3/4 would make sense because your DJ mixer has already applied the RIAA filter to the signal.

This is a total revelation to me. Thank you.

I don’t come from an old school sampling background and have only recently discovered the joys of vinyl. I originally bought the s2400 as a way to introduce limitations (compared to say, an MPC live or a daw) and to adopt a simple tactile workflow akin to a traditional musical instrument. The tonal character and the fact that it’s so bloody good-looking is of course a huge bonus.

There are things from the old school aspect of this machine which have both surprised and educated me (resampling 33 like 45, time-stretching, proper signal management, aliasing to name a few) and the way the physical inputs and outputs interact internally, is definitely another one of those things.

To tell the truth, when it comes to ins and outs, if the wire fits then I assume it belongs there! I have a rough understanding of impedance and signal strength/ types of signal, but still have a lot to learn obviously.

Once again, your guidance is much appreciated. If anything else springs to mind re inputs feel free to share it’s very interesting!

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