Tony's Do-It-Yourself Guide to
Speaker Replacement on WPC-Era
Bally/Williams Pinball Machines
Last updated: November 25, 2005
It's a commonly accepted fact that the stock speakers used in WPC-era Bally
and Williams pinball machines don't do justice to the audio tracks the
sound systems in those machines can actually reproduce.
Many pinball collectors choose to
upgrade the stock speakers for improved sound quality.
Speaker replacement kits are available for purchase from Pinball Pro, and many collectors
have commented favorably on the performance of these kits.
These speaker replacement kits offer a great deal of convenience. However, that convenience comes at a
the seller has overhead, labor costs, and deserves to make a profit for their efforts, so the
$65 subwoofer upgrade kit obviously can't contain a $50 speaker.
If you have several games and want to upgrade the speakers in all of them you're
looking at a sizeable investment.
If you don't mind spending a little time purchasing the individual component parts you
need, and if you're moderately handy with tools, you can save money and wind up with an installation
that sounds at least as good as the pre-packaged replacements.
This do-it-yourself guide will give you the basic information you need to choose replacement
components, some suggestions for components that I've found to work well, and the step-by-step
instructions to install your new speaker system.
The information in this guide was developed over the course of more than a
year, and is based on my personal experience restoring games for my own use and
for sale. I sincerely hope you find it useful! Feedback, comments, and suggestions for improvement are most welcome; please
send them to firstname.lastname@example.org.
Joseph "Tony" Dziedzic
First, let's make one thing clear: We are not trying to turn a pinball
machine into a high-fidelity speaker system. We are trying to improve the
quality of the sound produced by the machine's sound system. We can do this in
- Replace the back box speakers with wide-range units for cleaner and
more balanced sound
- Replace the cabinet speaker with a woofer to add additional bass response
We are limited in some ways by the physical environment with which we're
dealing. A pinball machine cabinet would never make a great subwoofer enclosure: the volume is too large for the size of speaker we can reasonably
use, and the cabinet can't be sealed or vented for a flat response curve.
Regardless, we'll still be able to vastly improve the sound quality over the
stock speaker system.
This guide does not discuss any of the esoteric schemes that the dedicated audiophile might try,
such as tapping the line-level output of the sound board and running the output to
active crossover networks, high-power amplifiers, and carefully selected speakers.
If you're that crazy you don't need this guide anyway!
This guide is written for the pinball collector who would like to improve the
sound quality of their Bally / Williams WPC-era pinball machine and is
comfortable using power tools. You should know how to use a jig or sabre saw, a drill, a circular saw or table saw, and a router. You don't have
to be a Yankee craftsman and you don't need a tool collection that fills
a barn to be successful. On the electronics front, if you can strip wire, solder
wires to terminals, and crimp connector pins onto wires you're all set.
The material in this guide is provided for informational
purposes only. If you choose to use this information you do so with the
understanding that you are solely responsible for any personal injury or
property damage that may result. You should read the entire guide before
beginning any modifications to your game.
This material is copyrighted, and may not be copied or reproduced without
written consent. You are of course welcome to print a copy for your personal
Safety tip: Wear eye protection when using power tools!
I've made the assumption that the avid pinball collector will choose to
replace the back box speakers and the cabinet speaker: this guide is
written with that assumption in mind. Replacing all three speakers is the best
way to improve the overall sound reproduction quality. I've also included enough information that you can be successful should you
choose to replace only the back box speakers or the cabinet speaker.
This guide is divided into a number of sections for easier reference. The
best method is to proceed through the guide by clicking on the NEXT links at the
bottom of each page. The HOME link will bring you back to this page.
The "how to choose and what to buy" sections:
A number of people contributed to this guide. Nearly two dozen
reviewers from the ranks of rec.games.pinball took the time to go through this guide and provide very useful feedback; a great big THANK YOU to
everyone (Barry, Dan, John (x4), Kevin (x4), Scott, Martin, Mark, Ross, Chris,
Scot, David, Tom, Phil, Matt, Mat, Daniel, and a few others I've probably missed). Special
thanks go to Cliffy for the pictures of the Bally-style back box speaker panel,
John P. for donating a Bride of Pinbot display panel, and to Martin for modeling some of the speaker and cabinet combinations.
Ready, Set, Go!
OK, that's enough preliminaries. Roll up your sleeves and let's get started!
NEXT: how to choose replacement speakers
Copyright © 2005 by Joseph A. Dziedzic. All rights reserved.