K and K pickup preamps

[kmmando]

I have K and K pickups fitted recently to my bouzouki and Sobell mandolin. The preamp I tried out first has proven to be unreliable in a live setting, and I wondered if anyone has comments on the K and K range of preamps? None of them appear to have any mute switch. Which when swapping between instruments could be an issue? And do the two input preamp ones work for using two instruments alternatively?

Any other comments on the K and K pick up useage very much appreciated!

many thanks

Kevin Macleod

[almeriastrings]

Kevin,

As you are in the UK I would take a very close look at the Orchid Electronics preamp:

http://www.orchid-electronics.co.uk/acoustic.htm

and the Headway offerings:

http://www.headwaymusicaudio.com/

These do feature mutes and are both built to very high standards. Considerably higher in spec and performance than the K&K units.

[Markus]

I use a turbo tuner stomp box tuner in my signal chain. Passes the signal through cleanly when not in use, mutes channel when in use.

Having a mute on the preamp, for me, would be redundant though useful at times. If you must have a mute, the Headway and others get great marks as preamps and have them.

[DavidKOS]

My positive experiences with the K and K Big Shot were with no preamp at all. The output of those pickups can drive an amp or PA without the preamp that the older pickups like Barcus-Berry, etc. needed.

Which K and K pickup are you using that needs a preamp?

[Shelagh Moore]

My K&Ks generally work well without a preamp but for those occasions where they need a little bit of boost I've had good results with both a basic Fishman GII and a Schaller in-line preamp. The latter is particularly useful as it has a mute switch and phase switch as well as the usual bass, treble and volume sliders.

[Mandobart]

The need for a preamp is not determined by the millivolt output of the piezo's but by the impedance mismatch between the pickups and the amp/pa. A regular guitar amp made for magnetic pickups is not suited for the 10 megohm impedance of a piezo pickup, and some PA's also will not work well. I have also lucked out and got a good sound without a preamp on occasion, but that is the exception. A PA or acoustic amp with a high impedance input will give good results with no preamp. I have never had a preamp hurt my sound, and with some gear it is vital to getting a good amplified sound. If you've ever experienced the "piezo quack"; a tinny, thin sound thank impedance mis-match, not the output of your p'up.

You don't need a preamp necessarily, but you do need something to effect an impedance match. That is what a standard direct input box (DI) does. The simplest way is to go with a passive DI. I've never used one. I've tried the ART tube preamp, the Behringer ADI21, the K&K Pure and finally the Redeye. Believe the reviews you've read about the Redeye, it IS all that. Great simple unit, solidly built. Best amplified sound I've ever experienced on my acoustic instruments. Nice built in solo boost. No mute. You can buy the L.R. Baggs Venue if you just have to have the mute; like Markus I use an in-line tuner to both mute between sets or for instrument changes (and also to tune).

[shane8002]

I use the k&k pure preamp it's great I use a tuner pedal as my mute

[Patrick Sylvest]

K & K Pure and one of these for me. Works great!

http://www.musiciansfriend.com/acces...strument-cable

[Brian Court]

I use a Radial PZ-Pre -- Excellent piece of equipment. It has many great features;
Two channels to switch between instruments
Notch & resonance filters eliminate feedback
Pre & Post Radial DI outputs for PA and monitors
Power booster and mute for more control on stage
The Radial Tonebone PZ-Pre™ is the most powerful acoustic preamplifier ever to be put inside a pedal. And when we say acoustic, we do not just mean acoustic guitar - we mean ANY acoustic instrument including banjo, violin, cello, mandolin, contrabass, bouzouki or lute. The magic lies in the combination of high performance 100% discrete class-A PZB piezo boosters, an ultra-quiet preamp circuit that will adapt to any pickup system and a host of connectivity options that will put you in total control.
http://www.tonebone.com/pzpre.php


The PZ-Pre is equipped with two inputs for quick instrument changes on stage. These can also be combined to blend two pickups together if you so desire. Features include a powerful yet warm sounding semi-parametric EQ to tailor your sound, feedback eliminating controls including a dual-Q notch filter to surgically remove feedback, a high-pass filter to cut low frequency resonance, and a phase reverse switch to eliminate hot spots on stage. It is also equipped with a host of outputs: a ¼" hi-Z instrument out for an on-stage amp, a pre-EQ balanced XLR output for the PA system and a post EQ XLR out for stage wedges or in-ear monitors. A dedicated tuner out with mute switch lets you quietly tune on-stage. There's even a combination power booster - effects loop

[DHopkins]

I have K&K in my Breedlove Legacy FF. Sounds great. It's accompanied by a K&K Pure Sound preamp. Great combo. The preamp does operate on battery only. I have used the mandolin without a preamp and it always does quite well. I try to use a preamp when I can so I can cut the mid-range down a little and lessen the pick noise.

[almeriastrings]

The need for a preamp is not determined by the millivolt output of the piezo's but by the impedance mismatch between the pickups and the amp/pa. A regular guitar amp made for magnetic pickups is not suited for the 10 megohm impedance of a piezo pickup, and some PA's also will not work well. I have also lucked out and got a good sound without a preamp on occasion, but that is the exception. A PA or acoustic amp with a high impedance input will give good results with no preamp.

Absolutely correct.

K&K transducers are perfectly standard piezo elements, and abide by the same 'rules' of physics as any other piezo element. The "High Impedance" input on most mixing desks and normal (electric guitar) amplifiers is likely to be far lower than truly optimum. Ideally, something in the 5-10M range should be available, with a minimum of around 1M. Although you will get sound from sub-optimal inputs, it will be compromised sound. There is no way around that.

Most of these preamps use very similar circuit concepts. The main differences tend to be in the 'extras' offered and in how they implement the EQ. You can build a pro-grade, basic high impedance preamp with about $10 worth of parts and a little metal box..

[Tim Griffin]

Red Eye.

[kmmando]

Fantastic responses, lots to take on board, many thanks to all!

Kevin

[kmmando]

Any Red Eye stockists in the UK, anyone know? Can't see any online ....

[Austin Bob]

I think which preamp you choose can depend a lot on the type of music you are playing and the mix of other instruments.

I have a K&K pickup in both of my mandolins and after some trial and error I ended up with the LR Baggs Venue DI.

• The sound is not quite as pure as the Red Eye, but close enough and it runs on battery. The Red Eye has a power cord with a big "wall wart" on the end, and I had no place to plug it in a church.
• I use the Venue in a choir setting with two guitars, a recorder, bass and 12-15 voices, so any purity of sound gets lost in the mix anyways.
• The Venue is built like a tank, and has a mute switch, a tuner, and a boost for solos.
• I set the PA flat, then dial in my tone on the Venue. It is easy to reproduce it next time even if someone has changed all the settings on the PA's input.

If I were playing in a bluegrass or even a folk type string band I might have made another choice. I also have a Pickup the World line driver that I sometime use in other settings, and it works well.

[Mandobart]

The sound is not quite as pure as the Red Eye, but close enough and it runs on battery. The Red Eye has a power cord with a big "wall wart" on the end, and I had no place to plug it in a church.
The Venue is built like a tank, and has a mute switch, a tuner, and a boost for solos.

Bob - The Red-Eye (built in Austin) runs on 9 VDC battery or phantom power from the PA. It has no wall wart input; it can't be plugged in. The Red Eye is also very solidly built, and has a boost switch for solos.

[Astro]

I dont know what any of this means but my Fishman platinum pro eq (almost 10 yrs old now--its plastic case not the newer aluminum one) has an impedance of 10.

Its this one : http://www.fishman.com/product/pro-e...num-preampeqdi

Somewhere along the way, I was told the preferred impedance for these piezos is 1.

Then above someone said its beteen 5 and 10 ? Does it matter ?

My Fishman does work. But is there something that could sound better ?

[Austin Bob]

Bob - The Red-Eye (built in Austin) runs on 9 VDC battery or phantom power from the PA. It has no wall wart input; it can't be plugged in. The Red Eye is also very solidly built, and has a boost switch for solos.

Sorry, you are correct. I was thinking of the Tonebone, not the Red-Eye. My mistake.

[almeriastrings]

I dont know what any of this means but my Fishman platinum pro eq (almost 10 yrs old now--its plastic case not the newer aluminum one) has an impedance of 10.

Its this one : http://www.fishman.com/product/pro-e...num-preampeqdi

Somewhere along the way, I was told the preferred impedance for these piezos is 1.

Then above someone said its beteen 5 and 10 ? Does it matter ?

My Fishman does work. But is there something that could sound better ?

There is no problem feeding your transducer into a 10 Mega Ohm (10M) input. Problems tend to result when using lower impedance inputs that required as they affect the "loading" and frequency response.

Some further reading on this topic:

http://www.buildmyelectricguitar.com...er-mpf102.html

http://liutaiomottola.com/PrevPubs/P...Transducer.htm

http://tclutherie.hypermart.net/interface/index.html

http://www.zachpoff.com/diy-resource...-preamplifier/

All of the commercial ones are based around very similar circuits to these.

They may add, however:

1) An EQ stage (of varying complexity)
2) A balanced output stage
3) Other 'options' such as phase reverse, mute, phantom power operation, variable input impedance, etc. This latter can be useful as you can select from several different options to find the one that you think works/sounds the best in your particular circumstances.

[Astro]

So I think I hear you saying mine is likely as good. I would be willing to get the redeye or tonebone if they resulted in better tone but I dont want to spend the money if its going to be about the same tone.

The tone I've gotten with my mando (dual surface piezo//fishman pro eq) through a PA has been fine for live bar gigs with guitars, bass, vocals, and snare/kick drum for a folk rock thing. But I wouldnt be happy with the tone if I were playing as a solo instrumentalist in a quiet venue (good thing I'm not good enough anyway).

[almeriastrings]

Piezo transducers are... at the end of the day, still piezo transducers, and whatever you plug them into, they stay piezo transducers.

They have their uses, and can sound "good enough" (for some things) but they do not sound half as good, in my opinion, than a nice microphone. You can get a improved sound over a piezo also, by looking at non-piezo transducers. The moving coil Schertler DYN for example, or the electret condenser based AKG C411. Those are both very good as far as transducers go, but even they fall well short of a good microphone, used correctly.

[pops1]

The K&K pickup is a 1meg ohm impedance, so is their puremini peamp. The Orchard is also a 1 meg ohm. The Baggs is a 10 meg ohm, still works fine, but i feel the K&K and Orchard with and exact impedance match sounds better. The rule of 10 works, but ears are the best judge.

[almeriastrings]

The K&K pickup is a 1meg ohm impedance.

Technically, it is not. Test it. Put a multimeter across it.

The reason you cannot use that approach is that it would only work with resistive loads. A piezo transducer presents a highly reactive load, where its resistance varies with frequency. So there is no "exact impedance match" for such a device that is true at all frequencies.

[Astro]

Learned a lot here. Thanks all.

Yeah, I tried a mic in this band and it just didnt work. I had to stay a constant 1/2 inch off the mic to get a steady output and that was very hard to do.

The Piezos were cheap (30 bucks thanks to MandoBarts suggestion of JJB's), easy to apply (dual surface mount), and do work for this type application. And so easy to plug into PA and no feedback ever. I can be heard and I can move around. The tone envy doesnt bother anyone but me. Everyone else seems to think it sounds great.

If I could get a little better tone with a different preamp, I would be willing to buy the latest best gizmo. But from what I am able to glean so far, I'm probably ok with what I got.

[pops1]

Technically, it is not. Test it. Put a multimeter across it.

The reason you cannot use that approach is that it would only work with resistive loads. A piezo transducer presents a highly reactive load, where its resistance varies with frequency. So there is no "exact impedance match" for such a device that is true at all frequencies.

Understandable if you use a resistive meter, but using something that actually measures impedance and reading and talking to K&K and some of the other folks like Orchard and Baggs. This is on their specs and that's what they will tell you. Of course the impedance will vary, but there is an input impedance and measurable impedance each of these.