Myriad Design Stompville Altoids User manual

by Myriad Design
Altoids Piezo Preamp
(SKU SV802)
User Guide V1.0 – May 2017

Thank you for purchasing the Altoids Piezo Preamp.
Please note that the preamp is built into a genuine used Altoids* tin and the tin will likely not
be in perfect condition. Please expect small scuffs and dents and minor damage to the paint
finish. Such imperfections are not to be considered manufacturing defects of the Piezo
Preamp and are not cause for product returns.
The preamp is designed to buffer the output of high impedance piezo transducers as
typically used for stringed instruments (such as violins, cellos, basses, dulcimers, etc)
and percussion instruments such as cajons and stomp-boxes. The preamp may also be
used as a buffer for electric guitars to prevent loss of high-frequency tone do n a long
connecting cable. The preamp is professionally hand-built and the JFET transistors
employed are very closely matched. The preamp has very lo distortion and noise.
The output voltage of a piezo is comparatively large but its output impedance is very
high. The preamp has unity voltage-gain and provides current-gain to lo er the
output impedance of the piezo to allo it to drive a significant length of cable ithout
loss of high-frequency signal.
BATTERY
Before use, the unit must be opened using a cross-head scre driver and fitted ith a
9V battery. Any type of battery may be used (heavy-duty, alkaline, NiCd, NiMh or
Lithium), but, as po er consumption is extremely lo , a disposable alkaline battery is
recommended and ill likely last years ith moderate use. It is recommended that you
do not remove the cover from the sticky foam pad - just fit the battery and sand ich
the battery lead bet een battery and the lid. Friction ill keep the battery from sliding
about.
There is a red LED bet een the input and output connectors. The LED ill illuminate
hen it is time to change the battery. Do not be alarmed if the LED lights during a
performance - there ill be enough charge left in the battery to get you to the end.
Ho ever, the LED takes a comparatively large current, so you should change the
battery at your earliest convenience. You may observe that the LED lights briefly hen
you remove the input connector (thereby disconnecting the battery).
CONNECTING THE CABLES
You may note hen you open the unit that the connectors have three contacts.
Nonetheless, you must use a mono (2-pole) jack plug in both the input and output
connectors.

The preamp powers up when you plug a cable into the input jack. Disconnect
the input cable when the preamp is not in use.
CONNECTING THE INPUT
Connect the piezo transducer or output of your instrument to the input of the preamp
using as conventional 1/4" Jack guitar lead. This lead should be as short as comfortably
possible.
CONNECTING THE OUTPUT
Connect the output of the preamp to the instrument or line input of a mixing desk,
DAW or combo/amplifier instrument input using a conventional 1/4” Jack guitar.
Alternatively, you can connect the preamp via one or more effects pedals. The preamp
should be the first item in the effects chain.
TECHNICAL STUFF
The unit has an input impedance of about 10Meg Ohms. It has a voltage gain slightly
less than unity. There are no input protection diodes fitted, so if you plan to use the
unit for a hydrophone or other instrument hich may be subject to mechanical shock
creating high piezo voltages, you should consider fitting input protection. See
http://stompville.co.uk/?p=879 for more details. The unit ill function ith a supply
voltage bet een 4V and 24V d.c. The nominal current consumption is about 200uA,
but if the supply voltage is less than about 7.3V, the LED ill light and increase the
current consumption to about 2.2mA.
WARRANTY
The Altoids Piezo Preamp is offered ith a t elve month return-to-base arranty.
Please contact [e-mail] if you have a problem ith your preamp. If the
preamp is found to be defective due to a component or manufacturing defect, the
preamp ill be repaired or replaced (at the sole discretion of Myriad Design) and
returned to you. In the event that the unit has suffered user damage or misuse, a repair
may be offered at nominal cost plus return postage. Postage charges for return of the
unit to Myriad Design ill not be refunded. Your statutory rights in the United
Kingdom are not affected.
*"Altoids" is copyright The Wm. Wrigley Jr .Company. Their rights are ackno ledged.

Copyright 2012-17 Myriad Design. All rights reserved.
Disclaimer.
The information contained herein is provided in good faith. Myriad Design has no
control over the ay the product is implemented or integrated into a system.
Therefore, Myriad Design offers no actual or implied arranty of fitness for purpose
and Myriad Design ill 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
.stompville.co.uk · [e-mail]