BQFS-PBP Piezo Buffer/Preamp 2026 - Brand New - One Year Warranty!

To provide some background, I am a retired electronics technician with over 50 years of repairing and modding basses and amplification equipment.

This preamp is built around the "Till" circuit which is a proven circuit that provides about 3db gain, offers high input impedance (about 3Megohms), low output impedance, and has been around for years.

I developed this kit to help bass players improve the sound of their piezo pickups. This applies to both upright basses and electric bass guitars.

This started when I bought a bass guitar with a piezo system whose sound, in my opinion, was unusable. Too "clacky," which is a comment I hear about a lot of piezo systems.

First I built one and installed it in an Ibanez fretless 6 string (now sold). I was surprised how much better it sounded, to the point where I could actually solo the piezos and they sounded good, much better than my prior bass equipped with piezos made by GraphTech.

For additional proof of concept, I designed and built a pedal for an upright-playing acquaintance. The pedal used my Till preamp (version 1) and a three-band EQ. Sounded excellent!

I find surface mount technology difficult to deal with so I had the circuit board redesigned by a friend of mine, and had it completely fabricated offshore. This enabled higher reliability and consistency since the JFET I use is unreliable in through-hole format.

I am furnishing these in "kit" form to make it easier to install. Instead of requiring you to solder directly to the small board, I am furnishing plug-in leads so there is no risk of over-heating the board when soldering the connections to your instrument.

Why this circuit works so well:

In order to properly "load" the piezo pickup(s), they need to "see" a high impedance load. The Till circuit provides an approximate 3Megohm input impedance. Then, the circuit converts it to a low impedance output which helps to reduce noise and matches the output impedance of most bass preamps.

It is not necessary to use a volume or a tone control with this circuit, but if you do, you can use a value of around 25K ("B" or linear taper for the volume control, and "A" or audio taper, aka log taper, for the tone control) and any "tone cap" capacitor value of approx. 0.047Uf (microfarads), but you can feel free to experiment with any value cap you'd like. Just be sure to install these on the output (low impedance side) of the circuit.

The circuit also provides a mild, unadjustable, boost of approx. +3db.

You can also find dual concentric ("two pots in one, with each element individually adjustable) pots in case you have a limited number of holes or just don't want to drill any more holes in the top of your bass or its control panel. A typical B50K dual may be found on Amazon. Just search for "dual concentric potentiometers." Anything more specific than that may not return the ones you are looking for (trust me, I found out the hard way).

If you plan to install this in a bass with magnetic pickups, you will also need a blend control to mix the piezo and mag. signals. For this, I recommend the excellent EMG ABC (active balance control). Another excellent control is the also active Richter Electronic Engineering MX-1 or MX-2. The MX-2 is my preference as it has a built-in trim pot for ease in matching levels. The cost for each is about the same. Each is readily available and the price, last I checked, was similar. The EMG may now be less expensive than the Richter since it is made domestically, whereas the Richter is made in Germany.

The circuit board is very small, approximately 1" by 1/2" and will fit in just about any control cavity.

Installation Instructions:

Installation is very simple. On one side are two wires, White and Black. The White wire is where you attach the input from the piezo pickup(s) and the black wire is circuit ground or common. On the other side are three wires, Red, Black and White. The Red wire is where you connect the battery (it runs just fine off a typical 9v battery). Black is another ground wire, and White is the output. The Black wire on the input side and the Black wire on the output side are common, so you can use either one for common ground.

Although the boards themselves are fully assembled when I receive them, I solder the end connectors and attach the wires myself.

There is a deliberate opening near the Input side. You can use that to attach a wire tie if you wish.

Each preamp is tested twice - once when I finish assembling it, and again prior to shipment.

Each one is covered by my one year parts and labor warranty.

I do NOT accept returns or give refunds because it is too easy to damage these by improper installation. But, if yours does malfunction in any way, if you send it back to me I will replace it at no charge to you (other than postage back to me that should be under $7).

All returns must be approved in advance.

Please ask any questions before placing your order.