Myriad Design Phantom Piezo Preamp V2 User manual

Myriad Design
Phantom Piezo Preamp V2
6517V2
(SKU SV206, SV207)
User Guide V1.0 – Dec 2017

SCREEN/SHIELD
USE SILVER-LOADED
SOLDER FOR THIS
CONNECTION
XLR Output
Pin 1 - Ground
Pin 2 - Hot +
Pin 3 - Cold -
Myriad Design
Phantom Piezo Preamp 6517V2
User Guide V1.0 - Dec 2017
Connect the piezo transducer to pins 2 and 3 on the input connector. It does not
matter which way around you connect pins 2 and 3. Connect pin 1 to the shield.
If your transducer has only two connections, connect the signal to pin 2 and the
shield to pins 1 and 3.
Thank you for purchasing the Phantom Piezo Preamp module V2.
The preamp is designed for integration into a musical instrument, an art installation or a
hydrophone and its purpose is to buffer the output of a piezo transducer element.The
preamp is professionally hand-built and the JFET transistors are very closely matched. The
preamp has very low distortion and noise.
The output voltage of a piezo is comparatively large but the impedance is very high.The
preamp provides some voltage-gain (approx. 12dB) but mainly lowers the output impedance
of the piezo transducer to allow the piezo to drive a significant length of microphone cable.
The unit must be connected to a mixing desk/console/sound board balanced microphone
input using a standard balanced XLRM-to-XLRF microphone cable.The mixing desk/console
must have phantom power facility of 12-48V.The unit does not incorporate a battery or
other power source.
The preamp serves the same purpose as a D.I. box. However, the preamp will have better
performance than a DI box because the cable between the piezo transducer and the piezo
preamp is very short. Think of the module as functionally equivalent to a phantom-powered
condenser microphone.
If the module is incorporated into a wooden case, such as a stomp box, cigar box guitar, or
cajon, you must create a shielded environment for the module and the piezo element either
with a metal box, or with self-adhesive copper shielding (or aluminium shielding).
For further information on shielding, search YouTube for“shielding a guitar”. Ensure that the
piezo element is not in electrical contact with the shielding.

The preamp module is physically supported by the output connector. There is
no need for additional support for the preamp circuit board.
Selecting a Piezo Transducer
Piezo transducers come in many variations. Generally, the larger the diameter, the
better the low-frequency response. Search Ebay for “piezo pickup”.
Version 2 Input Protection
Version 2 incorporates back-to-back zener diodes which clamp the maximum input
voltage to approximately ±4V (8V peak-to-peak). If you do not require input protection,
please clip the diodes out with side-cutters.
Using The Preamp
Piezo transducers have good frequency response and high output voltage. The preamp
will drive at least 100m of low-capacitance microphone cable without significant loss of
high-frequencies.
· Connect the unit to a microphone input on your mixing desk/console/board.
· Switch phantom power on.
· Consider using the PAD attenuator (if available and if necessary) to avoid overloading the
microphone preamp.
· Use equalisation (EQ) to alter the tonal quality of the piezo transducer.
· Use a limiter and/or compressor to reduce dynamic range or avoid overloads.
Panel cut-out (actual size, front view)
Ø22 (0.866”)
Ø3.2 (0.126”)
(typical of 2)
19.8 (0.780”)
19.8 (0.780”)
Allow minimum 7mm (0.275”)
clearance between the connector
mounting hole and the enclosure
min 7mm

Note:
The Phantom Piezo Module has been hand soldered using a proprietary
no-clean-flux solder. This is so we do not have to use environmentally
unsatisfactory solvents to clean flux residue from the circuit board.
There is no need to clean the circuit board further.
Copyright 2 15-17 Myriad Design. All rights reserved.
Disclaimer.
The information contained herein is provided in good faith. Myriad Design has
no control over the way the design is implemented or integrated into a system.
Therefore, Myriad Design offers no actual or implied warranty of fitness for
purpose and Myriad Design will accept no liability for consequential loss or
damage. This design is not authorised for use in any safety-critical system.
Your statutory rights are not affected.
Myriad Design · United Kingdom
www.stompville.co.uk · [e-mail]