The S4 runs at a minimum of 5V/500mA. Output level increases when the AC adapter is used. Regardless, output power/voltage is completely unrelated to audio quality.
The old Mk1 S4 does the same passthrough as the MC 3000, sending the Aux input directly to the Master Output without a computer connected.
The MC3000 does more than passthrough, it contains active analogue circuitry on both non-digital channels, and plugging in the adaptor does not change the output levels - you can do it mid-mix - just the lights become brighter. Read up on input and output impedance and noise/interference, and you will understand how output power affects sound quality. Or just plug the two into a non-studio desk and hear the difference (because non-studio desks have a lower input impedance), or run the signal through a long cable (because with lower levels the noise level is relatively higher, so amplification amplifies the noise by more).
A lower input impedance means the recipient of your signal will demand more current for a given voltage (power, ie, watts = volts x amps). Your output stage is of a given power, (determined largely by how much heat the ICs can dissipate - an amplifier works by holding back voltage). So if you increase amps, and your source power is fixed, you decrease volts. The audio signal is volts, so it is decreased. Also, signal level ICs are designed to work at low current. The S4 is more sensitive to current than the MC3000, as the S4 amplifiers are lower power. This you can prove simply by turning both to max (but make sure you turn the desk or amp down between tests or you could blow your speakers when you switch to the MC3000). The headroom, or the level at which you are “in the red”, is determined solely by the voltage levels.
Noise is also increased at lower voltage levels. Noise comes from electro-magnetic radiation. The amount of electro-magnetic radiation on a given wire and route is fixed, and comes from mains wires, radio signals, etc. If the signal is +/-5V (for example), and the speaker needs +/-20V, the amplifier needs to amplify the signal by a factor of four. If the signal is +/-10V, the amplification factor is two. The noise plus the signal is amplified by the factor. If the noise level is +/-0.3V, then when the signal is +/-5V, the factor is four and the noise reaching the speaker will be +/-1.2V. If the signal is 10V, the noise reaching the speaker will be +/-0.6V. Although comparing the S4 and the MC3000, the noise factor is much lower, not least because they both have balanced outputs, which reduce noise. (Balancing works by having two signal wires, one the inverse of the other, so noise affects both in the opposite way and can thereby be cancelled out.)
The signal-to-noise and distortion specs don’t look that amazing on the MC3000 spec sheet. There’s much more to sound quality than the somewhat insignificant maximum output level, since the vast majority of noise will be from the active components rather than across the balanced wires.
How can you measure “current sensitivity” by raising voltage? And why does current matter at all in a line-level connection?
From memory I would say both have effectively zero noise so good point, that paragraph was theory in answer to your voltage comment but off-topic. But there is a huge difference between the levels and power they produce, which is clearly audible even on studio monitors which presumably have reasonable input impedance, let alone club desks.
I think I’m misunderstanding both your questions in that second paragraph. By measuring current sensitivity by raising voltage, are you saying that it is equally relevant to compare both controllers at low levels? I’d disagree as you’re running the amp circuits throttled and comparing sub-optimal setup. In practice the difference is easy to hear when both are properly set up. And on line level current, I’d say the components at line level are not designed to cope with power, so current is especially problematic, but are you saying line level should be as close to zero current as possible anyway?
Level difference is of course obvious, but not important. The S4 puts out a more than adequate level for any PA system - the standard for PA line level is +4 dBu, and the S4 has a maximum of +18dBu.
Again, how does changing voltage output level measure anything related to current?
Yes, line level should always be negligible current; if your line inputs are drawing current there must be a serious fault in the unit.
I’ll summarize as we’re now going round in circles. Agree on line current, I am not making assertions on current based on voltage, and the key difference is output impedance.
When I plug an S4 into my KRK8 monitors or anything but the best desks, the sound degrades, and was not as good as my MC3000 is. My MC3000, on the other hand, drives even the most useless desk more than adequately, and is much easier to engineer into a system. This is because of the buckets of power it outputs and its low output impedance.
Feel free to critique any aspect of those assertions. I’ll respond if I feel I can add anything, hopefully constructively rather than antagonizingly.
On the KRK8s it may be colouring rather than output impedance. On desks it is definitely output impedance.
All the best makar1, no offence intended.
@technicaltich @maker1
Without sounding patronisiing, it’s a refreshing change to see some sensible discussion round here. Rather than the usual descent in to abuse.
Keep going guys, …i’ve learnt quite a lot in the last page or two. (& i’m having another reconsider of the MC3000!!)
Both controllers get the standard “good audio quality” in reviews, since there is basically no audible difference between midrange sound cards and above. I’ve read through many complaints about the S4, and have not come across any about its audio quality.
Did you conduct any side-by-side tests, blind or otherwise, between the two controllers? And how did you determine that output impedance was the determining factor? The S4 seems to be significantly ahead based on specs for distortion, SNR, crosstalk, and frequency response.
Thanks @thisisian, I was worrying we were chewing on the debate a bit too much.
The main factor I appreciated moving from the S4 was the windows drivers. I didn’t do blind or even side by side tests, nor even use the same laptop (the reason I finally abandoned the S4 was my new laptop, which I bought specifically because I thought a brand name laptop might work with my fresh replacement S4, was USB3, which the S4 blue-screens - my patience snapped).
But I often struggled to get a good punchy clean sound when connecting the S4 into soggy desks or amps, whereas I never struggle with the MC3000. I did get hum with the S4 - I haven’t mentioned this because I suspect it was the laptop transformer and a mains earth loop - but this might affect the noise. My theory about it being impedance is because they were pretty much peers when feeding decent desks, but the S4 degraded when feeding poor desks or the junk you often connect to at parties; and because the levels coming from the Denon were astronomically higher. I wasn’t surprised that something running with 10 times the power supply would have a lower output impedance.
However I also appreciate what might be the colouring of the Denon. I work a lot with my KRK8s, which have a very club, punchy, crisp, solid but controlled sound - good, wide-spectrum kicks or live drums with some crunch in their distortion come through in every bit of their glory. The Denon really excels at this sound when pushed right - the separation and staging is phenomenal, and there’s always plenty of energy but it is immaculately precise and restrained. It reminds me of the Vestax scratch mixers - they were heavy beasts and you could push them, even mixing sloppily into the red, and the kicks would just sound fuller and even more gorgeous, and the rest would stay just as crisp, hence my love of engineering with the Denons - it is plug n play. The S4 was a clinical sound, certainly precise, but with poorer quality output stages there wasn’t the separation in the mids - they’d start to feel clouded and a little gutless. I’ll admit I didn’t side by side test, but I’m as certain as I can be that this impression isn’t psychological as it was an ongoing experience over several years fiddling to get the best from the S4, and marveling at the MC3000 - going from the S4 to the MC3000 was like the difference between a £200 CD player you’ve loved for years, and a £700 CD player - you don’t suspect it will really, actually make much of a difference to the pleasure you experience, and then you’re awe-struck. I’d also say the Denon specs don’t do the machine credit. Still now, a good few years after buying the Denon, if I don’t use it for a few weeks and come back the sound is exhilarating. Again, this might be colouring as well as tech sheet specs.
I would differ on reviews and whether there’s an audible difference between good mixers. I’m really disappointed by the lack of attention sound quality is given in reviews - I’d love half a review to be purely on the colouring, like reviews of amplifiers or speakers. Sometimes (and I’m not commenting on your point makar1, just chewing the fat), DJ reviews just cite the resolution and frequency (“this is 48khz/24bit so is as good as it gets”). This is like evaluating a car by stating how high the speedometer goes. In my opinion sound quality is the invisible elephant in the room that no-one realizes affects them. And this isn’t just for wierdo geeks with oxygen free silver interconnects (um..technicaltitch looks furtively), greats like Gilles Peterson and DJ Scruff travel with a lorry load of delicious kit because every little hint of quality you can squeeze out makes a difference to people’s perception, even if when you ask them they’d claim to enjoy music from laptop speakers just as much.
PS Love your dnb mix makar1, we have similar taste.
How long did Dub Phizix take to release Clock Ticks? That was cruel. And what about Ivy Lab this year?
Denon is much better felling than NI S2
I got the Denon MC3000 and it got a good and stong feeling. The controllers is nicely heavy, and professional. The S2 is mainly in plastic and look like a cheap toy, at least that the feeling I had playing with it …
An old controller now, but still a good one. Very limited in what you can do with remix decks if you want them, but as a basic two channel controller with good controls for effects its great. I did what I think is a fantastic tsi file that also incorporates slip mode and a few other functions into it. I remapped sync turning the syc button in normal mode to toggle slip mode on and off, but you can still sync a decks by pressing shift+sync. I also turned the + and - pitch shift buttons into buttons for increasing and decreasing ??% for the tempo faders. And a couple of other small tweaks. meant I could use almost all of the Traktor 2.6 functions with the Denon. No longer have mine but would be happy to send you the tsi file so you could have a play with it.
Now that I think of it I also assigned the unused video buttons to do various things such as load and stop in preview deck, start and stop record mix, and toggle between browser and deck views. Really good little tsi it was actually!
Indeed, I see it s a good optimisation.
I did couples few trick on my mapping as well, especially in the FX buttons. You could updated your file in the midimap section. I am sure it would interest many people, and I will give it a try 
Which controller to use now ? if I leave Denon, I will go to pioneer I guess …
A tank. Gone back to controller free, have the XDJ-RX and use Rekordbox analysed usb stick. TBH i have more fun.
Waw that’s a nice setup 
Congrats buddy ! Do you feel a difference with traktor and rekordbox in the use and feeling ?
TBH it is a LOT more fun to use in terms of tactile and visual feedback. It’s also nice not to be looking over at a screen. It has waveforms, but I turn them off and go by ear which I think makes ME more involved in the music and therefore play a better set, but that is just me and I don’t claim that is true of everyone. It can do most things Traktor can, and does everything I need, although Traktor does make looping much easier and you have to pay a bit more attention wth Pioneer gear doing it, but working a little bit harder is no bad thing. The only problem is its big and heavy, and I miss the Denon’s size and weight for just rocking up at an informal house party if I travel anywhere further than a cab ride.
I get your feelings. I am using traktor since 4 years and I know it pretty well. It s a nice and powerul app which allow to do many stuff.
I wanted to try the rekordbox since a lol time and after spending hours in forums, I finnaly mapped my denon MC3000 on the app (including knob and fader). I played with it couples time this week and I get lot of fun. The 2 waves side by side are pretty useful. For internal routing I feel the EQ is doing very nice. The autoloop work good and adjust itself to the kicks. The library and music management are much better looking and useful. And the fx are much better.
I will see in the long run, but it s a good feeling overall )