KLH Nine

The KLH Nine is the superb sounding and history making design that Arthur A. Janszen (AAJ) created at JansZen Laboratory and put into field tests in 1957. This design was then taken on by KLH and put into production at the end of the 1950's, with AAJ as V.P. Engineering.

The KLH Nine was the first truly full range electrostatic speaker. Even fairly recently, it was declared one of the 12 most significant speakers of all time, and has been written about repeatedly (example). Production began in late 1959 and continued for nearly twenty years. The list price was initially about $2,000/pair, which translates to about $17,500 in 2019 dollars (https://westegg.com/inflation/). 

Over the past decade or so, we've accumulated a fair number of vintage pairs for refurbishment or upgrade to your specifications. 

Although there are pairs still in service without having required repair, there are several things that can go wrong with this model after 40 to 60 years:

  1. Selenium diodes were the only high voltage, solid state rectification devices available in the 1960's. After 60 years, they're prone to failure. Failure causes reduced or missing sound from tweeters, woofers, or both. This will not happen to the modern silicon diodes that we replace them with. 
  2. Carbon composition resistors were the only type available in those days, and after 60 years, they can change their value and even fail. Failure of these devices also causes reduced output. We replace them with metal film resistors that are stable. 
  3. Soot and other particles can become electrostatically precipitated onto the woofer panels and high voltage wiring. Thsi can cause leakage paths for the high voltage. Leakage can cause reduced output and popping sounds. Our rebuilds include a thorough cleaning, and add an acoustically transparent barrier membrane only three microns thick. (Human hair averages about ninety microns thick.)
  4. The Bakelite (phonolic) terminal boards develop leakage paths over very long periods of time. This can cause reduced output or poppping sounds. We replace them with new ones made from a circuit-board grade epoxy/fiberglass material. 
  5. The original vinyl-insulated wire loses its insulating properties, unlike the mPPE-insulated wire that we replace it with.
  6. The PVDC membrane film used for the woofers, which was the only thin film available with appropriate tensile properties, has become stiffer and tighter over the decades. This typically causes the bass to roll off below 90 to 100 Hz, instead of the 40 Hz original design spec. This will never happen to the special PET material that we replace it with. 
  7.  The connection to the tweeter membrane coating can fail inside the tweeters, whch causes the treble to be reduced or disappear. The coating and coating connection that we apply during panel rebuilds is far more robust. 

We're uniquely qualified to address these issues.

We offer a refurbishment service as well as an upgrade service. You can order pairs that start out as one of our original vintage pairs, or you can send us your own pair for refurbishment or upgrading. 

Refubishment. This entails completely dismantling these speakers right down to the sticks, and then rebuilding them to better than original condition, with better joinery and finishes, fully rebuilt woofers and tweeters, and modernized supply units fitted with components that will not age appreciably over many subsequent decades. JansZen refubished Nines come with a full, transferable, two-year warranty. 

Our own pairs, refurbished to better than new condition, are rebuilt to order for half the inflation-adjusted original price, namely $8,750. Lead time varies depending on our backorder queue, which includes orders for our new products. It's generally at least six weeks, and can be as long as fourteen weeks. 

Upgrade. In addition to what's entailed in the refurbishment service, the upgrade also includes replacement of the original tweeters with our new ones, which requires several modifications; changes to the supply; creation of an acoustically transparent window ahead of the tweeters; furnture grade finishing of the frames; and replacement of the grill cloth with fine linen. The price for those built from our stock of original pairs is $12,250/pair.

If you supply your own KLH Nines, you will get credit for them. The credit is a function of condition, and varies from $200 for pairs in poor condition to $2000 for functional pairs in cosmetically fine condition with no rust, mold, or stains. After ordering, we ask that you wait to ship them to us until your order is next in the backlog queue. 

Again, we have only a small number of pairs already here for refurbishment or upgrading. 

You can find more information and details about our KLH Nine services from the main menu above. 

To inquire about KLH Nines, please refer to the contact page.