K&K Pure Mini — Great Natural Sound
 

I installed a K&K Pure Mini in an OM I built as part of a course this morning. Very happy with the natural quality of the sound and that I won’t have to mess around with changing 9-volt batteries.

It’s quite easy to install yourself with the jig they provide given that doing anything inside the closed guitar is a bit fiddly. The unit is very compact and minimal—no knobs or batteries or barn doors. But best of all, the sound is quite true to the genuine acoustic which I’m delighted with. I’ve tried a number of pickups in various guitars that I thought were disappointingly synthetic sounding (with the Maton AP5 being a notable exception).

Was playing it through a Fishman loudbox mini.

Anyway, I’m very pleased with the pure mini. Thanks K&K!

My favorite by a longshot - and lord knows I've been through about everything!

When eq’d and pre-gained properly they definitely are hard to beat...they sound just like the guitar more or less. I’ve put them in plenty of guitars. That being said I haven’t tried Dazzo or Trance Amulets and I hear good things from the pro’s and engineers.

+1 on the K&K Pure Mini. I put one in my J-50 and it has become a great guitar to use when I play with a group. I usually play thru a bass amp for a nice big sound (I often play bass anyway) but even thru a regular amp it has a nice acoustic sound that the original UST pickup didn't have.

I watched the YouTube videos on installation - looks straightforward enough but after buying the pickup and having it sit in the box for a few months, I ended up having a luthier install it for $75, well worth it.

I'd love to get a few and have them installed on my guitars. I can't standing the 9 volts...

I've gone through nearly every pickup system on the market. There are some advantages to active, battery powered, on board systems. I've had a lot of success with many of them. But, with the exception of very few, they all tend to acoustically dampen the guitar. That's something I find troubling when you've either invested in a high quality guitars, or made one in your case.

Every pickup system starts with a component that "hears" the sound. Then, the signal get passed to something that can process the signal and amplify it. The active systems do the "hearing" and the processing and pre-amplification before it leaves the guitar. So, you can plug into just about anything and get a predictable result.

The distinct advantage to the K&K is also its weakness. For a feather weight pickup that does no acoustic dampening, it "hears" very well. However, sometimes it hears too well in the lower registers. And, the passive K&K needs to pass through an impedance matching preamp to deliver a more flat response signal to the amplification device. The bigger the mismatch between the passive K&K and the amplification device it is plugged into, the less predictable the result will be.

I've come full circle on this a few times, and I suspect I probably will circle back again in the future. It all comes down to how and where you amplify your guitar. The more control you have over the signal chain from guitar to audience, the more attractive the K&K can be.

Big fan here too. Depending on the guitar sometimes it takes a bit of eq to get a smooth response but then to be honest that usually is the case for just about any pickup.

True, but it's not like exotic or expensive gear is required to tweak its EQ.

That depends on the tone you're looking for and the gear you're using. Finding a preamp with the recommended 1 Meg Ohm can be a bit tricky. Finding one with 1 Meg Ohm input impedance and a prametric EQ is more tricky. Finding one with 1 Meg Ohm input impedance and 2 bands of prametric EQ, and a high pass filter is more tricky still. Trial and error has produced surprising results for some people with all manner of equipment.

For instance, I recently "reunited" with the TC Helicon Play Acoustic, which has 1 meg Ohm input impedance, and just edited all of the parametric EQ information. I got an excellent clean tone from it.

I also invested in the ToneDexter, which is the latest and certainly the "greatest" preamp system available for correcting a pickup to sounds like a microphone using impulse response.

The hurdle for many of us with the K&K is not the kind of gig where you setup your own pedals and equipment. That is reasonably straightforward. It's the "plug and play" performance where someone hands you an instrument cable and says "strum" to get their level check. This is especially true for people who finger pick and need to tame the lows and bring out the highs.

About 1/3 of the time I can plug in a passive K&K into someone's PA system and get something that sounds like a guitar when played with a pick and bare fingers. 1/3 of the time I get something that can be used with a pick, but sounds like mud with bare fingers. 1/3 of the time I get something that sounds like mud regardless. Most of the time the board doesn't have mid controls in the 500 Hz to 1000 Hz range, which is where most of the over reproduced mud comes from.

For those situations, I have the K&K pure preamp. It sounds good, but it's big, clunky, and not really convenient to clip on your belt or guitar strap. It sometimes scrapes and scratches against the instrument. I'm presently working with a forum member who has developed custom IR files for me to use with another smaller preamp system. This has a lot of bugs, and isn't ready for prime time. But, I have hope that we can eventually use my ToneDexter wave maps with a (truly) portable preamp device.

@Martingitdave - I would be really interested in hearing what Para Eq settings you have dialled in on the Play Acoustic - I have struggled and struggled trying to make that box work well with a K&K...! Thanks.

All of my acoustics have K&K pups. Love ‘em!

Along the same lines Dave, I'd love to hear how you go about tweaking the parametric EQ onboard the Play Acoustic seeing as how there are no knobs to "sweep." I'm not naturally adept at EQ but just being able to cut some low mids is a big help in hearing how I sound when I practice with the Play Acoustic and Bose L1C.

Maybe I've been lucky, but the gear I've tried my K&K with, a Mesa Rosette and the TC Play acoustic, have no problem with the ohm compatability. Also no problem plugging straight into a Bose L1C, although I should clarify that by saying there isn't an ohm discrepancy -- but it doesn't sound good (which is why I got the Play Acoustic) due to too much low-mid information.

Also, if I do the quick and dirty setup thing at open mics, usually through fairly commonplace DI boxes, I don't think relatively unsophisticated EQ settings can be blamed for performances that didn't go over that well. So far I'd say I'm getting the appropriate audience reaction based on my performances whether or not the guitar tone is ideal. In ideal performance situations where people are paying, EQ settings become much more important.

I actually get a lot of compliments on my guitar tone although I realize it could be more advanced, enough that I'm hesitant to switch guitars even though the neck is a little wide for me. And I'm sure a lot of that has to do with the combo of K&K in my particular guitar. It seems like K&Ks invariably go well with Collings guitars (and I'm sure many others).

One aspect is the guitars that are being played. Double 0 guitars are better balanced as a whole and aren't as difficult to get similar sounds. Dreads are not the guitars for these types of systems.

Impedance

Much has been written on the topic. Simply put, try to use preamps that have an input impedance of 400KOhm to 1MOhm. Too little impedance and you get too little bass. Too much impedance and you get too much bass. And, we're talking about losing or gaining information for the whole low end below 250 Hz.

From memory:

If you go into the setup menu and choose advanced editing for body rez you will get the following EQ toys to play with:

Low shelving EQ
High shelving EQ
(2) Parametric mid frequency controls.

These toys, plus some sort of ambiance reverb effect which I assume is used to increase sustain, are "BodyRez." And, yes, you can do this on your own if you want to. But, they generally do a nice job of knowing where the hot spots are.

If you are not familiar with a parametric EQ, they can seem a little intimidating. But, armed with a little background, it's actually quite simple.

Here is a link to explain how a parametric EQ works:

https://www.wikihow.com/Use-a-Parametric-Equalizer

My recommendation for EQ it to use it surgically. I seldom add. I use it to take away.

TC Helicon Tricks for EQ

TC seems to do somethings a little different from others. They like to use two mid frequency bands with a Q of 2.04 centered around ~500Hz and ~900Hz. These two work in tandem to create a wave shape in the mid that eats away at the annoying frequencies pickups produce. You can use one or both. Most analog parametric EQ products use a wider bandwidth Q of 1.0. In my experience, the ~2 range is actually better. So, here I agree with TC Helicon. That said, all of this is totally adjustable to your taste.

What I do:

1. I use a compact PA system with a built in digital mixer. It includes a real time analyzer function that lets you visualize the frequencies in real time. You can get an idea of where you might need to notch for feedback, or where you might have some spikes in your signal that need to be tamed.

2. Play through the 5 Body Rez shapes and pick the one that sounds the best to you overall. This is just a starting point. Don't get too hung up on perfectionism.

3. Go to the advanced pages in the menu. Start with the shelves. If you want a little more bottom end, or top end, start by bumping the gain 1-2 dB at a time and play a little. Once you get it where you generally like it, try moving the shelf frequency a few clicks in each direction. When you increase the low shelf you are starting the bass boost a little "earlier" and vice versa.

4. The mids is where the money is. When you cycle through those 5 pre-programmed settings to choose which you like better, mostly you are hearing the result of the sweepable mids. Just like the shelves, you can play with these too. It's important to make one change at a time and play a little to hear what you've done. For instance, you can decrease the Q value to make the cut wider. Or, like in my case, I will shift the center frequency for the mid cut a few clicks in either direction and listen with each click. You'll be surprised what a 40 Hz shift can make. If you want to net out a cut altogether, you can just change the gain to zero, and it is effectively off.

What a K&K needs:

This is debatable, but what I hear is this:

1. The K&K acts sort of like an internal microphone. It picks up a lot of low and low mid frequencies that are bouncing all around the inside of the guitar and reflecting off the back, etc. This is unlike an under-saddle pickup that mostly "hears" the strings. I call this "mud."

2. People argue that the K&K is all mud and no highs. I agree to a certain extent. But, like a mic, once you surgically remove the mud from the signal you can suddenly hear all the highs that have always been there, but where hidden under the mud.

3. Depending on the guitar, I hear at least two "humps" of mud. One hump in in the low end (below 250Hz or 150 Hz in feedback range) and a second hump in my dreadnought shaped guitars around 800 Hz. The first hump is usually due to the resonant frequency of the guitar. The second I attribute to listening from inside the guitar. Once you remove those, it sounds much more natural to me and the highs start to come through. This is important because most mixing boards have a wide Q mid frequency adjustment that is centered around 2.5KHz. That's way too high to be effective at removing any mud from the K&K. And, the lows are centered around 80Hz, which is way too low for the shelving filter to be effective. That's why lots of players opt for mixers with a sweepable mid frequency.

4. Some might hear a third hump around 1KHz, 1.5KHz, or 2KHz. I would be hesitant to cut much up at the higher mid frequencies because those help a pickup cut through the noise.

5. The highs might still be a litle too weak to cut through the mix, so feel free to bump those a dB or several according to taste.

OR

Buy a ToneDexter, which has the equivalent of 2000 parametric EQ bands that get automatically set by the computer to mimic what it hears from a microphone. It does this magic in about 2 minutes, and it doesn't cost much more than most of the parametric EQs out there. And, as a bonus, it was designed for 1MOhm impedance because the creator is a fan of the K&K style pickup.

Either way, you'll be doing fine from the audience's perspective.