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We sell two models of compact preamps, the Fishman Powerjack and the Pure Preamp from K&K. Both are well suited to the needs Experimental Musical Instruments people are likely to have, but they have very diffferent features. To help you decide which is best for your purposes, there's a comparison chart at the bottom of this page. The rest of this page is about the Pure Preamp. (Click here for info on the Power Jack).

THE PURE PREAMP

The Pure Preamp made by K&K Sound Systems will enhance the performance of magnetic pickups, piezo contact pickups, high-impedance microphones, and other high impedance, low-level sources. (It can work with low-impedance microphones too, but not optimally).

The Pure Preamp is practically noise-free and the fidelity of the output signal is excellent. It’s wonderfully compact – just 2.5” x 3.5” x 1.25” (including the knobs). It comes with a belt clip, so you can wear it when you play, keeping cable lengths from the pickup to the pre-amp to a minimum. Or perhaps, if this works for your instrument, you’ll prefer to devise some simple way to mount it directly on the instrument. There is no additional wiring or soldering required; nor is it necessary to make any modifications to your instrument. You just plug in the cables from the pickup and to the power amp, and play. It has easily accessible volume, bass, midrange and treble control knobs – almost like having controls on the instrument itself. In addition, there’s a gain-control located inside the unit which allows you to adjust the input signal strength as needed for particular instruments.

High-impedance signals, particularly the ultra-high impedance signals coming from piezo contact pickups, tend to lose both fidelity and signal strength when they pass through cable runs of more than a few feet. The solution to this problem is to include a pre-amp in the signal path as close as possible to the pickup. The pre-amp will boost the signal, making it more immune to unwanted noise pickup, and it will convert it to a lower impedance, allowing for longer cable runs without loss of fidelity or signal strength. The K&K Pure Pre-amp is ideal for this purpose.

Further details: The Pure Preamp has standard quarter-inch jacks for input and output. Unplugging the input works like an off switch to prevent battery drain. It uses a standard 9-volt battery; battery life up to 180 hours playing time. Frequency range: 10 – 30,000Hz. Input impedance: 1 mega Ohm; output impedance: 10 K Ohm. Comes with a one-year warranty.

Price $96 Item #122

For more information on different types of pick-ups, their uses, and the pre-amp question, click here.

*The Pure Preamp replaces the K&K Power Pack preamp that we previously sold. The two are very similar in features except that the Pure includes a midrange control, and the housing is very slightly larger.

To aid your buying decisions, here is a comparison of the features of the two models of compact pre-amps that we sell.

Use with piezos:

• The Fishman Powerjack's very high input impedance makes it ideal for use with piezos.
• The K&K Power Pack will also handle piezos. Its somewhat lower input impedance means it is not technically ideal, but the difference between the ideal impedance match and the less than ideal one is scarcely discernable.
  

Use with other sources:

• The Fishman Powerjack will do fine with magnetic (electric guitar-type) pickups. It is not suitable for low impedance sources such as most microphones.
• The K&K Pure Preamp will do fine with magnetic (electric guitar-type) pickups. It is not ideal for microphones, but will still do a good job with them.
  

Mounting on the instrument:

• The Fishman Powerjack is designed as an onboard preamp -- it's made to be mounted on the instrument. Specifically, it's made to be mounted where the endpin of an acoustic guitar would go, but its small size and unobturusive shape mean that it can be mounted in other ways on any number of different instrument types. It's not well suited to being used offboard.
• The K&K Pure Preamp is designed as an offboard preamp. You can set it on a table or mount it on a mic stand nearby, or use the belt clip it's provided with. It is small enough that you might be able to mount it on the instrument, but not as conveniently or elegantly as the Powerjack. .

Controls:

• The K&K Pure Preamp has volume and tone controls readily accessible, and a special input level control on the inside.
• The Fishman Powerjack does not have controls.

Amplifiying the Signal:

• The K&K Pure Preamp can substantially boost the signal level, and with excellent clarity and fidelity.
• The Fishman Powerjack is not designed primarily to boost signal strength, but rather to provide high impedance pickups -- piezos in particular -- with the buffering and impedance-lowering they need for improved performance. Accordingly, the Powerjack provides only a very modest boost in signal strength.

Soldering or modifications to the instrument required?

• The K&K Pure Preamp requires no soldering or modifications to the instrument, assuming that whatever you want to plug into it has a cable and a standard 1/4" with a plug..
• The Fishman Powerjack is intended for permanent onboard installation rather then off-board plugging and unplugging. It requires soldering of the two wires from the pickup, and provisions for mounting the pre-amp on the instrument.and attaching the battery clip.

Price:

• K&K Power Pack: $96
• Fishman Powerjack: $56