HiZ ... impedance converter for electric guitar/bass & passive Piezo elements ...

A HiZ should be in every guitar case, where a passive pickup can come into play ...


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The impedance troubles  ...

Who ever tried to connect an electric guitar with passive pickups to a low-impdance input (e.g. PC, Line-/Aux input of HiFi equipnent,...) has expirienced the troubles:

  • hazy basses
  • powerless mids
  • trebles without any brilliance

A low-impedance input will just cut-down the "fragile" signal from high-impedance outputs of passive pickups in electric guitars/basses or bare piezo elements in acoustic guitars.

By interconnecting an 'impedance converter', that provides a high-impedance input for the passive pickup and can drive the current on the output side, that a low-impedance Line/Aux input needs, then the world will be in order again for the passive pickups:

  • crispy basses
  • powerful mids
  • brilliant trebles

HiZ is such a device  ...

A HiZ is equiped with high-grade operation amplifiers (Burr-Brown "SoundPlus" with JFET inputs), that provide exceptional slew rates and extremely low distortion and are therefore also used in high-end HiFi equipment. The characteristics of the JFET inputs is similar as that of tubes thus providing a 'silky' sound characteristic.

Instead of cheap replacement circuitry a high-precision rail-splitter from Texas-Instruments provides an exact 'virtual-ground' to the circuit.

Burr-Brown "Soundplus" Features
  • Superior Sound Quality
  • Ultra Low Distortion: 0.00008%
  • Low Noise: 8 nV/√Hz
  • True FET-Input: IB = 5pA
  • High slewrate of 20V/µs
  • Operation voltage down to +/- 2.5V

With a typical output amplification of 1:2.5 the input level from the instument is lifted, that even less sensitive inputs can be served well. A HiZ is for that concern also a level shifter to some extend.

An internal 'booster' can be geared-in to the output signal to push up the slew rate of the output signal and to lift the corner frequencies. That doesn't make the output louder - but gives a little 'freshness' and 'pinch' in the output sound characteristics.

HiZ Booster small

HiZ has a usual 9 volts accumulator built-in that you can use it simply without any power supplies everywhere you need it. To load the accu any 12V/DC power supply with a 5.5/2.1mm power jack (ground outside!) can be used.  HiZ is delivered without power supply so that you can use one which you already have. If you do not have such a power supply you can find one under 'accessories' in the shop. The accumulators we use on delivery are so-called "Ready-to-Use" (R2U; RtU) accumulators which have a significantly low 'self-discharge' and the load last a long time if the device is turned 'off' - maybe in your guitar case ...

HiZ deliberately abstains from an operation LED, since even a low-current LED would pull more power from the accu than the entiry circuit does when turned 'on' - that's for the benefit of operations time of the accu. The load circuit gets the accu within 2..3 hours to its nominal voltage which is enough for 2..3 hours operation in a concert or in the studio with accu operation and minimal load. The used operation amplifiers from Burr-Brown work stable down to a voltage of 5 volts (+/-2.5V)

After reaching 'nominal voltage' the load current for the accu steps to 'smooth loading' for the benefit of the accumulators life-time. The accu -practically- cannot be over-loaded, so you can have it continously loading for days or even constantly. The green "BAT-LED" shines brighter than the red LED (which indicates"power suplly connected"), if the accu is fully loaded. This state takes ~3..4 days to be reached while 'smooth-loading'. The operation time is ~8..12 hours of permanent use, if the accu is fully loaded - and even far more, if running idle (no input signal).

With a car adapter (instead of stationary power supply) the device can be loaded while you are driving your car or in the tour bus, that has a 12V board-socket.

Like all devices from musIC the HiZ also sits in an extreme quality aluminum enclosure . These enclosures can withstand even the roughest circumstances on stage.



  • Power supply 12V/250mA/DC with powerjack 5.5/2.1mm
  • Adapter cable 6.35mm (1/4") socket to 3.5mm jack (Mono)
    [For microphone inputs on a PC - or other LINE inputs with 3.5mm socket]
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