FAQ - 3ZB

How hard is it to install?
How big is the module?
Where do I connect the Pickup Ground wire?
Why is the pickup ground separated from the jack ground?
How do I ground the pots?
Why does it pop when I plug in the cable to the bass with the amp power on?
Why is there no sound for the first few seconds after power up?
How is the module mounted?
What if I don't know anything about bass guitar wiring?
What type of wire is used?
Why so many wires?
What types of switches are used?
What types of pots are used?
What passive EQ controls do you offer?
Too many knobs - I ALWAYS set my X control to the same position!
Do you provide knobs?
What colors of hardware can I get?
Do I hear more static noise in the High-Z setting?
What are the 4 adjustment pots on the module?
Does the active/passive switch bypass the electronic circuit to make it a passive preamp?
What is the frequency response of the tone controls?
What can't I get my peak frequency response higher in High Z-Mode?
Why does High Z-Mode sound exactly like Mid Z-Mode?
My bass has only 3 holes for controls - can I use this preamp?
What if I don't want to drill a hole for the Battery indicator LED?
What is heat shrink and why would you include any with my preamp?
What if my bass control holes are 0.4" diameter?
Some of my wires do not seem to go anywhere?
Can I wire up the pots and switches myself?

How hard is it to install?: We have an example of an installation under Support/Documents or follow the Install link. We recommend that you have experience with a soldering iron and installing simple electronics. A Luthier or repair shop can do it for you if you are uncertain. The Install example shows how you can play test the unit early in the installation.

How big is the module?: The preamp is 2.0" by 1.0" by 0.55". This is the same x by y size of a common 9 volt battery with a connector snapped onto the top. The thickness is slightly thinner than a battery. Note: there are a lot of wires which exit the top of the module. The drawing for the module is in the mechanical drawing .pdf.

Where do I connect my Pickup Ground Wire?: Pickups have at least 2 wires, call them Hot and Common. The Common(s) must be connected to the one wire that have one end free coming from the Module that is Green stripe on White. If you have two pickups, they join together with the module wire. (Hot wires also go to the module, Black stripe on White goes the Bridge or a Single pickup, Blue stripe on White goes to the Neck pickup.)

If you have a 3rd wire and it is a braided shield, this is a Ground wire and can be connected to the Cavity Ground. Do NOT connect the Common wires to the Cavity Ground. Doing so would increase the power pull and cause distortion.

If you have 4 wires you may have two Hot wires for split coils. Check with the pickup manufacturer on how to connect the 4 wire pickups for parallel or series operation.

Why is the pickup ground separated from the jack ground?: We developed a split power supply so we can DC couple the pickup signal to the input of the amplifier. This allows us to move the capacitive coupling to the output signal, which has a low impedance drive source, instead of having it coupled at the pickup side which is a high impedance signal. This provides a cleaner signal path.

How do I ground the pots?: The barrel of the pot is metal and is normally grounded by pressing against the shielded cavity.
Traditionally in guitar electronics people soldered directly to the back of pots. This was a poor idea for several reasons.
1) You need to use a very aggressive flux in the solder (acid core was traditional). If the flux is not thoroughly cleaned off it will reactivate when it gets humid and can corrode the metal and cause the pot to fail.
2) You have to heat the heck out of the part. This often shifts the resistance and permanently increases the noise of the resistance element. Many pots have internal plastic parts that can be damaged by this much heat.

Why does it pop when I plug in the cable to the bass with the amp power on?: Due to the standard power switching used for the battery connection (see the previous question) the battery is connected to the input of the guitar cable during the time the cable is sliding into the jack. Most people develop a habit of partially pulling out the other end of the cable before inserting the connector into the bass jack. Some people use a guitar cable with an integrated disconnect switch. Planet Waves and others have cables with this feature. Neutrik has a "Silent Plug" (NP2C) out that we haven't tried but it looks interesting.
Why is there no sound for the few seconds when the unit first powers up?: We mute the sound during the battery test time. The hardware is initializing the power supply level and checking the switch positions to set the Z- mode etc. The muted output is much better then listening to the uncontrolled hardware startup.

How is the module mounted?: We provide durable double-sided sticky pads to go under the module, secure but still removable.

What if I don't know anything about wiring an electric bass guitar?: Installation is simple if you have experience with installing music electronics. However, typical hand tools for soldering wire connections and assembly are required. If you are uncertain about the installation we recommend you have a guitar setup or repair technician or a Luthier install it for you. The module and controls are all pre-wired to make it easy to install; you will need to connect the pickup wires, install the LED battery indicator, put the switches and pots into the body mounting holes and attach your grounding to the jack.

What type of wire is used?: The wire is a Mil-grade thin Teflon jacket over 24 AWG with 19 sub-strands for high flexibility. Most of the wires have a base color and a 2nd colored strip. The advantage of using Teflon is the insulation can be very thin and will not burn back from high heat during soldering. The disadvantage is it is harder to strip unless you use a very sharp stripping tool.
Why so many wires?: 18 base configurations, not including all the control options. We could have eliminated any wires that you don't need for your specific configuration but you might want to change the configuration later. Instead, we keep all the preamp wiring intact so you can change your tone or volume configuration in the future. Note: there are three different base modules, 1 with no tone circuit, one with a circuit for 1-3 bands, third is for 4 band control. The good news is we'll pre-wire it for you.

What types of switches are used?: We use DPDT (on/off/on) for the Z-mode switch and QPDT (on/none/on) for the preamp override switch. We tried several brands of switches and selected Carling Technology switches which had good performance at a reasonable cost.

What types of pots are used?: The pots we use are high end audio grade with low noise metal film resistance elements (often called industrial controls). The pots are small 9mm units which provide you with more vertical space to stack the electronic module and battery. Our pots are all 100K ohms with the volume pots having an audio taper and active tone controls having a linear taper.

What passive EQ controls do you offer?: We do offer a tone type control but our design intent for passive mode is for use as a backup, not as the normal playing style. We explain why in more detail on the Active/Passive page, but to summarize - the advantage of our design is that it gives you control of the impedance load on your pickups when in active mode. In passive mode your pickups are affected by the downstream impedance of the cable, external preamp, and any controls.
Too many knobs - I ALWAYS set my X control to the same position!: If you want a quasi-fixed position control, for example, if you always add/delete a little mid range, then we can wire up your unit with a trimmer which is a small plastic part which stays hidden in the control cavity. These controls are 25 turn adjustments so you have a very accurate set point. The size of the adjuster is roughly 3/8" square by < 1/4" deep. This allows you to setup the bass as desired then forget about that control. If you change your mind later, then you can move the adjustment to a new setting. The cost of this option is the same as a regular pot but you need to put a note with the order to get it wired up this way, and include an email address in case we have questions.
If you do not want one of the tone controls and you do not have room to store the control in the body of the bass, you can remove the control pot by cutting off the pot and insulating the wires. That tone control section will default to a flat response.

Do you provide knobs?: We can supply knobs with the preamp but they are an optional item. See the purchase menu under knobs. You can also use your own knobs. Single controls have a 6 mm shaft size. Stacked controls have both a 6 mm and 8 mm shaft. All knobs need a set screw to hold onto the shaft.

What colors of hardware can I get?: The switches are chrome and we provide a chrome, a black and a gold washer/nut set so you can coordinate the look with your other hardware.
Do I hear more static noise in the High-Z setting?: Yep - This is true for any comparable preamp. It is a physics problem - a high input impedance amplifier will have more noise due to increased Shot Noise in the input resistor. Excess noise normally increases in higher Ohm resistors. Also the pickups with this loading will pickup more voltage noise from various sources in the environment. While we can not beat the fundamentals of physics - the circuit design and parts were selected to reduce the noise level as much as is possible given the impedance tradeoffs. You can also really help reduce this noise by Shielding the Pickup Cavities.

What are the 4 adjustment pots on the module?: The two closest to the wires, the top edge of the module, are the High Z-mode capacitance adjustments. These adjustments modify the location of the resonant frequency peak of the pickups. More information is available on the Impedance page and on the High Z page.

The two on the lower edge of the module, away from the wires, are the Low Z-mode gain adjustment. This adjusts the loudness of the pickups in this mode, more information is on the Low Z page.

Does the Active/Passive switch bypass the electronic circuit to make it a passive preamp?: Yes - in passive mode you could remove the battery and still play, that is the ultimate test of whether a preamp is passive. Some people use the term passive preamp to mean an active preamp without tone controls, which is also an option with the Audere preamp. There is a bit more info on choosing passive mode in the Features section.
What are the frequency responses of tone controls?: For the passive style treble roll off
    Treble rolls off starting at about 16k adjustable down to 800 Hz
For the 3 band active module
    Bass shelving ending at 240 Hz +/- 15 dB
    Mid center 250, 500, 860 Hz +/- 10 dB
    Treble shelving starting at 1.92 KHz +/- 15 dB
For the 4 band active module
    Bass shelving ending at 172 Hz +/- 15 dB
    Mid1 centered at 200 Hz (wide control) +/- 10 dB
    Mid2 centered at 800 Hz +/- 10 dB
    Treble shelving starting at 1.92 KHz +/- 15 dB.

What can't I get my peak frequency response higher in High Z-Mode?: Many players prefer the resonant frequency in the 2k to 5k range which is the mid to upper range of a female vocal. The factors that determine the location of the peak frequency are explained in more detail in the High Z feature section, but capacitance is one of them and that can be changed with the High Z-Mode adjustment. The peak frequency location varies due to the pickup's design and if your pickup is of the very low variety, then there is a limit to what adjustments can be made external to the pickup. The adjustment range provided by the preamp loads the pickup from a small Capacitance, lower than any guitar cable / amp combination, to a Capacitance larger than most 50' cables. If you can not get the resonant peak location high enough (this would be a rare type of pickup or unusually high peak location request) then you can change out the pickup to one with a higher resonance location. In general - look for a pickup with a ceramic magnetic or neodymium magnet as these will have fewer turns of wire due to the strong magnets. If the pickup has 4 wires brought out for the windings use Parallel Hum cancelling instead of Series Hum cancelling.

Why does High Z-Mode sound exactly like Mid Z-Mode?: If your pickup is a non-traditional design with a low amount of coil inductance and a low amount of capacitance, then the High Z-Mode resonant frequency could be located at a frequency too high for your speaker system to response too. Dial in more capacitance using the adjustment on the preamp. This will bring the resonant frequency into a range where you can hear it.
My bass has only 3 holes for controls - can I use this preamp?: There are lots of options for what to do with your 3 holes. One of the possible configurations is: 1st hole for a volume/volume; 2nd hole for the Z-Mode switch; and the 3rd hole for a Treble/Bass tone control.

What if I don't want to drill a hole for the Battery Indicator LED?: The LED comes standard on all units. It is really nice to know your battery level is cool before you step onto the stage. I would recommend you allow us to wire it up and if you decide you do not want it then cut off the LED and insulate the wires with the enclosed heat shrink pieces. But it's your preference and if you add a note to the order saying delete the LED then we will.

What is heat shrink and why would you include any with my preamp?: Heat shrink tubing is a plastic tube which is used to insulate wiring. The tubing shrinks or reduces its diameter when you heat it. It comes in various types of plastic, sizes and shrinking ratios. You can shrink it with a hot air source (a match can be used with care). Just be careful you do not apply too much heat to the tube or other parts on you bass. We supply you with a few pieces so you can insulate your wiring if you need to.

What if my bass control holes are 0.4" in diameter?: We supply rubber rings to fit over the switches and single pots to expand the diameter. This works well for most applications. If you require a special sized spacer ring then most Luthiers could help you out.

Some of my wires do not seem to go anywhere?: On all 3ZB preamps there will be a varying number of extra wires which do not go anywhere and are covered with heat shrink. The extra wires allow you to change the configuration of the preamp in the future. For example, if you decide to go from volume and volume controls to a volume and balance setup - the extra wires allow the preamp to be rewired to the new configuration. If you do not have space for the wires or dislike the concept of having the extra wires attached to your preamp then we can delete them. Just put a note in the comment field with your order...

Can I wire up the pots & switches myself?: Sure, drop us a note with the order - but do you really want to? Our background is building very high quality instruments and we have a process in place to ensure that you'll receive a well built, fully tested unit. If you want to shorten the wires or change your configuration you can de-solder the wires and make your modifications. It will be easier to change the connections one at a time.