Vintage Speaker Maintenance - Finding a Diamond in the Rough

     Getting into the audiophile hobby and setting up a serious listening rig can be a daunting task, especially for those with limited budgets that can’t afford the more often than not multi-thousand dollar investments that a new system entails. I fall into that category but luckily I discovered my audio passion from exploring vintage gear from the golden age of hifi. Technology has come a long way since, but that came from years of research and a lot of legendary equipment that set the standard at which modern sound is compared to. With a bit of luck a few of these legends find their way to the marketplace or local garage sale at fair price offering a discounted entry to audio bliss. Sometimes there won’t be an issue to be found, but usually over years of storage there will be necessary repairs and maintenance required to bring the equipment back to life.

Vintage Speakers

    There is some real value still to be had in buying vintage speakers, some of the best performers can still stand toe to toe with some modern offerings based on current market value. That being said, much like purchasing a used car, there will be a level of maintenance and repairs needed to get them to spec, or even working at all.

    One of the first things that tends to go with vintage speakers is the foam on woofers and midrange drivers. Not all speakers use foam, but it is easy to spot if the foam is in need of replacing. It usually completely deteriorates and falls off leaving a gaping ring around the woofer cone. As tempting as it may be, don’t connect the speakers with broken or missing foam, as you run the risk of damaging the driver or even your amplifier. Foam repair is a simple but time consuming process where you can’t cut corners. The driver must come out of the cabinet, all leftover original foam removed and cleaned down the the bare metal of the basket for a proper repair. I like to use isopropyl alcohol, a scraper and light sandpaper if necessary.  Once the basket and cone have been cleaned to bare surfaces, you can then proceed with the instructions given with your foam kit. Also look and see if anyone has posted a how to for your specific speaker, they may have tricks or specific needs in the process, not to mention it can help you learn about your new addition to your home.  

The Drivers 

    A speaker is a sum of individual drivers that separate the audio signal based on specific frequency to minimize distortion. If it sounds complex, it is, and you should always beware of non matching drivers or non original, as it could be an indication of how they were treated. Every driver is carefully selected and the crossover designed specifically dialed in as a whole, it’s rare you can just swap a driver and it work as well as the original. As you are researching your speakers, you may come across some of the weak points that you need to check for function or repair, the weakness for the QLS being the midrange drivers and the solder on the back of the tweeters. These had seen some work at some point and the left cabinet needed significant work to reverse some of the quick repairs done in the past. The midranges needed rewired to match the crossover diagram and half needed rebuilt due to vulnerable leads on the outside of the driver that tend to dry over time, cracking and severing connection. (I will do a video on a popular repair method for these. Don’t toss them out!)

Cabinets and Crossovers

    The QLS made their way to their first home in 1976. That’s about 46 years old at time of writing this article. That’s 4 decades of damage from being moved, moisture seeping into the cabinets, and the dielectric of the crossover capacitors drying up causing drift. These had seen quite a bit over the years, so I am posting a separate write up of my undertaking of replacing the capacitors and fixing the bases. That article can be found here. The wood on the bases had been exposed to moisture causing rot and were starting to flake apart, while the tops were dry as could be, not having had any oil in years. On smaller speakers I have seen others use teak oil or some other restorative oil, but due to the sheer size of the QLS it would be difficult to move these to a properly ventilated area where smell wouldn't be an issue. I have been using monthly applications of Old English Lemon Oil and have had great results. Over time the darkness returned to the cabinets as the oil seeped into the dry wood, bringing new life to these tired old speakers. Not to mention the lemon scent isn't overpowering and reeking of chemical smell that will overtake your room. 

Extra Resources 

    There are numerous groups of enthusiasts on Facebook and Reddit with loads of experience and knowledge when it comes to vintage audio.  While a new system is plug and play and easy, you can save some money and build a better connection to your system by restoring your own vintage speakers and saving them from being tossed in the garbage, while also building your own troubleshooting skills for when something may go wrong in the chain. Google and Hifiengine.com have been tremendous help when it has come to crossover diagrams and design changes. The plus side of an older piece of equipment is that many people have had their own experiences and documentation to help resolve any issues that have come up, or even how to amplify system strengths.