Anyone else using the kemper with an external DI?

    I've had a kemper a while and really love it. When I first bought it, I tried it in several configurations to find the optimal setup.


    I'm using it with a UAD Apollo (1st gen), which is by no means a top of the range interface - that said, using the JFET DI instead of the kemper's input is a very noticeable improvement (extended range/clarity, more realistic feel, exactly the difference I experience between different DI boxes). I'm going in and out of the kemper via SPDIF which is nice as it saves my analogue inputs/outputs for other things and presumably the conversion in the Apollo will be better than the Kemper's.


    There is definitely a difference in the sound of the D/A of the Apollo when I make the kemper the master clock. I had never previously noticed as drastic change in the sound of the D/A when changing the clock (I have a few ADAT preamps that I've run as the master before), so it seems the clock in the kemper is definitely something that could do with some improvements too. It'd be great to be able to run it as a slave, and also at other sample rates (although the Apollo does have an option on the SPDIF inputs to convert the sample rate).


    It definitely makes me curious to try some other DI boxes with the kemper - I don't feel any one DI box will be perfect for every guitar and bass, and I'm sure there are better options out there than the Apollo. I'll most likely pick an RNDI up further down the line as I can make direct profiles of amps with that too....

    From what I've seen most people don't use a DI box to record dry/DI tracks used for reamping later on.


    Most people do 2 methods:


    1) record with TRS from the Direct Output on the back of the kemper set to GIT Studio (This sends a line level signal), sent to the input of their interface.


    2) record using SPDIF out of the kemper to the SPDIF input of their interface.

    Quote from Ezerath

    From what I've seen most people don't use a DI box to record dry/DI tracks used for reamping later on.


    Most people do 2 methods:


    1) record with TRS from the Direct Output on the back of the kemper set to GIT Studio (This sends a line level signal),…


    I'd indeed imagine most people would use the kemper that way - the configuration I'm using it in sounds better to me than using its own analogue inputs, and was wondering if anyone else had similar experiences?

    not me.


    I suspect either your DI is coloring your signal in a way which you find pleasing, but it is not more authentic (quite the contrary), or your DI signal is somewhat hotter and you experience a louder signal (the old louder = better)


    generally, the Profiler has no signature sound.
    I don't recall any of the numerous high profile pros using the Profiler (some of them for about four years now) ever making a similar observation.

    I don't doubt that the built in DI input on the kemper is good enough for most people, in most situations. That said, I'm also not naive enough to believe that the Kemper is the first ever unit to create a PERFECT DI box, an entirely linear gain stage, and amazing A/D conversion as well as its groundbreaking technology at a price far cheaper than anything else out there. The loss in fidelity when changing it to the master clock immediately makes me weary of its conversion quality.


    I'm sure it has been designed to be as neutral and uncoloured as possible, as is the case with a lot (but not all) DI boxes/preamps/converters. Without some clinical way of testing each section of the Kemper's input, its entirely inaccurate to claim the Kemper "has no signature sound" or is "more authentic" then every other piece of equipment out there - not least as there is no defined reference point for a perfect behaviour. Furthermore, with the given specs, I don't possibly believe the Kemper's DI is outperforming gear with superior specs.


    Just to use the Apollo's DI as a comparison:


    The Kemper has an input impedance of 1MΩ vs Apollo 2.2MΩ
    The Kemper has a dynamic range of ">108dB" vs Apollo 117dB


    There is no values given for the Kemper's THD+Noise so its not possible to compare these.


    Something like this (http://rupertneve.com/products/rndi/#tech-specs) has far better specs than what I'm using, and there are also far better A/D converters out there. Could they only offer an improvement in sound by somehow "colouring" the sound? I'd be interested to know how these values above constitute the Kemper behaving more accurately than other equipment. If the Kemper sounds good enough as-is to you, that's absolutely fine. If you have compared it against other equipment (cleaner/more character/whatever), and ALWAYS prefer the sound of the Kemper, thats fine too. But its wrong to blindly assume the Kemper's input is somehow more authentic or has no signature sound.


    All I'd suggest, is if people have the means, to try alternative DI's/conversion, as based on my experience, there is a notable difference (and in my opinion improvement) by combining it with other gear.

    Quote from Ezerath

    1) record with TRS from the Direct Output on the back of the kemper set to GIT Studio (This sends a line level signal), sent to the input of their interface.


    How I plan to do it. I'd use the non-line (direct) option but my interface won't accept it.


    Quote from easstudios

    The loss in fidelity when changing it to the master clock immediately makes me weary of its conversion quality.


    This has nothing to do with the D/A convertors used for the line outs 'though, does it?


    I thought this would relate to the digital I/O only. Am I wrong?

    Quote from Monkey_Man

    This has nothing to do with the D/A convertors used for the line outs 'though, does it?


    I thought this would relate to the digital I/O only. Am I wrong?


    Well the "clocking" aspect of the Kemper will be the same regardless of which outputs you are actually using as the processing inside the kemper is all digital (and the Kemper has to be the master clock at all times). Changing my interface's clock from master to slave means my D/A sounds worse while the Kemper is set as the master (fine temporarily for tracking, as long as I'm not recording anything else at the same time). I have no idea what the quality of the built in converters are (these have improved a lot/become much cheaper over the last few years). Without any tested figures and no way of knowing for sure, I'm happier doing to A/D and D/A conversions elsewhere....

    Exactly. So, because the clocking has no bearing on the Kemper's D/A, we agree that the quality is uniform therefrom.


    The question therefore is as to how good the convertors are / sound, and IMHO, they're top-notch. I can't imagine their being any better for the task for which they're employed.


    I don't use the digital I/O at all, but it doesn't surprise me that when you use the Kemper as a master, your other convertors don't quite sound as good as they may when you use higher-end and dedicated clock masters. This is, after all, is why the Big Bens of the world exist; there's been a market for these things for eons simply because proprietary (in-built) clocks of our various outboard devices aren't specified to perform the task at the cutting-edge of technological possibility. They're generally there for their utility - to be used in a pinch, but certainly not as permanent solutions in pro setups.


    For transferral of audio digitally from the Kemper, if you have to slave your gear to it, there'll be no problem as your interface's outs' quality will be of no consequence, something you alluded to. For this reason I don't really see a problem unless I'm missing something obvious.


    As for the DI thing, which was your main focus, I suspect that the plain-jane feedthru (guitar-level) is for all intents and purposes uncoloured. I'm guessing that the analogue out from which it comes, in this case, doesn't involve the D/A convertor 'cause the signal isn't digitised in the first place. The "studio-level" option, however, AFAICR, does involve an A/D stage in order to be able to digitally boost it to line level, and then, of course, the D/A stage at the output. IMHO, if any real-world, tangible difference is to be heard, it'd therefore be whilst employing this second, higher-level option. As much as I'd like to, and I mentioned this, I can't use the former method 'cause my interface won't accept guitar-level signals; I'll therefore have no choice but to opt for the boosted, latter method.


    That is, of course, unless I use a splitting DI box and send one out to the Kemper and the other to the interface. Will look at this as I draw nearer to recording. I watched the "DAW-AMP" box's video posted here on the forum by SinMix, and something like that would be ideal IMHO (not esoteric, I grant you), if not for the fact that cable repatching for reamping is required. A second, DAW input, to go along with the DAW out (where the out acts only as an out and not a combined in / out as it does currently), would be ideal IMHO; one could then leave everything plugged in and simply disconnect the guitar when reamping, something you'd do anyway in order to not introduce the additional noise. We'd also, in the case of the Kemper, require a second to-amp output so that it could be left patched into the rear reamp input. On the Kemper, the front cable would have to be disconnected for reamping too in order to activate the rear one and also reduce additional noise.


    All this futzing about suggests to me that a simple, splitting-DI box such as I mentioned earlier would be a whole lot simpler. Clean, equal feed to both DAW and Kemper for recording. Disconnect Kemper front input and reamp from DAW with permanently-patched-in feed to the rear, reamp input on the unit. Done. Waaay simpler. Less cables too.


    Cheers mate. Will keep an eye on this thread; it's what I've been waiting for, and saves creating one of my own.

    It's certainly an interesting topic.


    Quote

    I don't use the digital I/O at all, but it doesn't surprise me that when you use the Kemper as a master, your other convertors don't quite sound as good as they may when you use higher-end and dedicated clock masters. This is, after all, is why the Big Bens of the world exist; there's been a market for these things for eons simply because proprietary (in-built) clocks of our various outboard devices aren't specified to perform the task at the cutting-edge of technological possibility. They're generally there for their utility - to be used in a pinch, but certainly not as permanent solutions in pro setups.


    This wouldn't be an issue at all if it were possible to set the Kemper's clock to an external source. Sure, Big Ben's/etc exist but if the Kemper's clock is causing noticeable issues to my system, then it'd be nice to have the option to sync it somewhere else. FWIW, I'm not using any kind of dedicated outboard clock, and this is the only time I've noticed a perceivable drop in quality when using digital devices (compared against "cheapish" units such as MOTU 896HD/Mackie Onyx/Focusrite Forte). It's not so much of an issue when only using the Kemper by itself - more of an issue when recording multiple instruments at once, or working at different sample rates. With the most recent generations of converters, the benefits of external clocking has reduced fairly considerably (the Big Ben for instance has been discontinued). If the Kemper isn't equipped with a clock that compares favourably, even to standard interface clocks, then it would make a lot of sense to be able to run the Kemper as a slave to whatever the best sounding option is.


    Quote

    As for the DI thing, which was your main focus, I suspect that the plain-jane feedthru (guitar-level) is for all intents and purposes uncoloured


    I'm curious to where the "uncoloured" assumption comes from? Connecting a guitar to any kind of "load" is going to affect how the pickups react - if the impedance is too low, the high end will disappear (good luck getting that information back). Likewise, all DI's have a frequency response, noise/THD behaviours, dynamic range etc. These values are not provided by Kemper so "uncoloured" is baseless without some kind of reference point. It certainly fares better to me than my Little Labs Redeye did (lower impedance than the Kemper, caused loading to the pickups and a lack of high frequency information). I've also used DI's that cause the high end to become distorted and lack clarity resulting in noise from around 3k upwards - again the Kemper
    doesn't seem to suffer from this. Furthermore, the specs given from Kemper (although by no means bad) compare less favourably to other gear; if you deem the Kemper to be uncoloured, then by definition choosing equipment with superior specifications will provide even less colouring.


    What I have experienced, is compared to DI's with a higher impedance than the Kemper (2.2MOhm upwards, such as http://rupertneve.com/products/rndi/#tech-specs , http://www.creationaudiolabs.com/#!mw1studiotool/cp99 , http://www.uaudio.com/interfaces/apollo.html , etc), the Kemper has less information in the high end (a warmer tone). This may not be an issue with lower output pickups or if the intended tone is on the warmer side. When capturing my DI's, I'm looking to capture as much of the sound as possible rather than losing anything.


    Now as far as splitting your signal goes, a good DI box is critical here as its impossible not to affect the impedance - hopefully you have the opportunity to try a few different ones (and even compare to the Kemper's) so you can experience what I'm talking about. The MW1, for example offers a variable impedance on input and output which seems like it would be great for tuning the impedance to the desired guitar sound. The Rupert Neve DI has the ability to also be used a speaker load which obviously has its benefits for making direct profiles. I'm currently going directly into the Apollo DI and then in and out of the Kemper which has the benefits of only one A/D stage, and also keeps my analogue inputs free for other things.


    Now, I'm sure we can agree that its best to not blindly assume that the Kemper (or any piece of gear) is the absolute benchmark in DI's, A/D conversion, clocking, etc. I'm not saying it categorically isn't, but based on the specs they've provided, it certainly doesn't stack up as well as other equipment. That's not to say that if all I had to work with was the Kemper, I wouldn't just get on with it, but given the other equipment available to me its worth exploring various options and working with the best sounding AND most convenient workflow. I started this thread as I was curious if there was people out there (say with one of the DI's I mentioned, or equivalent) who had experienced something similar to me, and I'm still interested in how others may be incorporating such equipment in their set up.

    I totally hear you, brother.


    Amazingly to me, my fave DI of those I've used over the years is the one built into the Onyx desks - the "guitar" inputs switchable on channels 1 and 2 on the original 1620 and the 4-bus model, whatever it was called - 1640?. I've not really tested guitar through it much, but oh man, for my Stingray basses, I've seriously not heard better. Talk about detail, articulation and sweetness. I'm betting the Apollo, Rupert Neve and so on would somehow take this to the next level, but in the areas of sweetness and weight, where I'd expect budget gear to fall down, the Mackie shines unexpectedly.


    It's a great pity to me that I can't figure out a way to use this input in my setup. I can't split the input off prior to the circuit (for feeding the Kemper), for one thing, and the output (direct, via D-Sub) is line-level, which makes it great for DAW recording, but again, not for feeding the Kemper's guitar in.


    My Onyx is an original 1620 and isn't expanded (no digital I/O), which is what I wanted (all-analogue) 'cause I didn't trust digital all those years ago when I bought it new (and still don't!). This clocking thing we've been discussing is exactly the sort of distraction I was hoping to avoid by that old purchase choice, and I don't regret it a bit. When I buy interfaces, I ignore digital I/O. The noise floors, S/N ratios and THD levels of modern convertors are such that I don't feel as if I'm missing out on anything by going "all-analogue".


    Quote from easstudios

    FWIW, I'm not using any kind of dedicated outboard clock, and this is the only time I've noticed a perceivable drop in quality when using digital devices (compared against "cheapish" units such as MOTU 896HD/Mackie Onyx/Focusrite Forte).


    Yes, but all those devices are front-end inputs, assuming you're talking about the newer or the expanded (via card) older Onyx, as opposed to sound sources like synths modules, FX processors and... Kempers.


    Quote from easstudios

    Sure, Big Ben's/etc exist but if the Kemper's clock is causing noticeable issues to my system, then it'd be nice to have the option to sync it somewhere else.


    Agreed.


    Quote from easstudios

    If the Kemper isn't equipped with a clock that compares favourably, even to standard interface clocks, then it would make a lot of sense to be able to run the Kemper as a slave to whatever the best sounding option is.


    Agreed.

    Quote from easstudios


    I'm curious to where the "uncoloured" assumption comes from? Connecting a guitar to any kind of "load" is going to affect how the pickups react - if the impedance is too low, the high end will disappear (good luck getting that information back). Likewise, all DI's have a frequency response, noise/THD behaviours, dynamic range etc.


    Let me bring in some facts to the discussion:


    In general (and in the Profiler) the Spdif generation unit is a hardware device in the processor. There is no way to make it work badly or even improve it by software tweaks.
    However, you might have heard about potential jitter on the digital channel, caused e.g. by the Spdif cable, that could potentially harm the signal.
    Modern Spdif receivers should be able to re-jam the exact clock phase so no signal degradation is happening.
    The well known jitter is a constantly discussed topic in certain groupes, heated up by e.g. Spdif cable manufacturers.
    It should be no issue still, even with the worst cable or other deficites.
    If you feel that your system performs inferior when synced to an external clock, please ask the manufacturer of the synced device.


    Sample rate converters are also a target of discussions. But todays sample rate converters work with comparable technics, they should not degrade the signal at all.


    The signal-to-noise ratio is not a measure of coloring the signal, if you don't clip the device.
    A noise floor is not coloring the payload signal, it's a parallel signal. The electric guitar produces noise of a multiple level of any analog input or DI box out there.
    That's why noise gates are so popular.


    A guitar tapped by a 2 MOhm input might sound brighter and more brilliant than run by the Profiler input that features 1 MOhm of input impedance.
    However, 1 MOhm is the impedance of most tube amps (none has 2 MOhm), thus 1 MOhm will produce an authentic sound from your guitar.


    Specifications of a device do not define the sound quality!
    The only difference to that rule is the input inpedance of a guitar input.

    Appreciate the response - I'll certainly inquire about the SPDIF clocking as I was surprised to notice a difference. Presumably your response above means it's not possible to make the Kemper the clock slave in the future?


    Of course, it's not easy to scientifically compare different DI's to what's in the kemper - specs contribute nothing to what sounds better (ultimately opinion anyway), but it is still interesting to compare what information is available and what benefits they can possibly bring. There are many talented developers out there who I'm sure made their design choices with as much reasoning as the kemper :)


    For my tastes, I much prefer the feel of a higher impedance input - I've always found it impossible to dial that high end brilliance/clarity back in to a sound, whearas it's very easy to scale it back afterwards once captured.


    I commend you if you feel the kemper's DI outperforms all of the competition, and I truly believe you're entitled to that opinion. As long as I'm noticing a sonic improvement I'm , happy to mix and match, and pair up the right DI to guitar/bass depending on the job. It'd be great if the kemper had a way of mimicking the kind of behaviour of an MW1 where the impedance is continuously variable and cab be tuned to the specific instrument and desired tone.....

    Quote from easstudios

    For my tastes, I much prefer the feel of a higher impedance input - I've always found it impossible to dial that high end brilliance/clarity back in to a sound, whearas it's very easy to scale it back afterwards once captured.


    Try the Definition and Clarity parameters in the AMPLIFIER module. This let's you literally dial in brilliance even after the Profiling process. You could say it let's you tune or mod your amp.
    Clarity/high end etc. also depends a lot on the pickups. Vintage wound single coils offer a lot more in this region than hotter SCs or even humbuckers. And new strings, obviously :)

    One thing you could try is recording the analog signal from the master outs of the profiler. This would remove the Kemper clock from the equation and you are unlikely to witness any "degradation", though in my own experience with a relatively high end RME Fireface 800, the signal is not affected by the Kemper as master clock. Could this be a bandwidth problem with your interface? What have you set the buffer to? Perhaps you could try increasing it since you have many instruments recording simultaneously.

    We are working in different configurations with IZ Radar Systems, RME Digiface, Apogee's and digital consoles. When set as master the Kemper's clock signal via spdif never degraded or influenced the sound quality from any of the devices or of the whole system.


    The first generation 2012 Apollo Interface (mid class converter btw) seems to have issues with external clocking. This is not the fault of the clock source (Kemper). The issues are rather caused by the design decisions for the clock section in the Apollo, From a gearslutz Apollo User review:


    With all the conversion tests I had the opportunity to compare the Apollo on its own clock and on external clocks. I found the Apollo to be quite sensitive to clocking and I found it to sound noticeably worse when clocked to some converters. Now, I am from the school that believes a better wordclock cannot improve the performance of the internal clock in the unit, but that external clock can, however, change the sound of the converters that are clocking from it.

    This definitely seemed to be true with the Apollo. While clocking it from the Digidesign clock noticeably degraded the sound, I found the smoothness, depth, tightness, and punch of the Apollo's converters to improve when clocked to a Big Ben, at the expense of a little stereo width.

    Edited once, last by tobytoby ().

    The Stage offers a bunch of line level outputs, TS as well as XLR, which can be configured. One of these is the SEND 1 output, which by default sends a dry guitar signal. This signal can be used for reamping. This is also the output used during the PROFILING process to forward the dry guitar signal to the reference tube amp's guitar input. The use of an external DI box connected to the outputs of the PROFILER is meaningless.