This auction is for the most significant pair of high fidelity loudspeakers ever offered on eBay. While all of the Hartsfield, Iconic and Tannoy auctions are fun to watch, those loudspeakers are quite common when compared to this pair. If you have never seen nor heard of them, there is good reason. Very few were produced and even fewer remain today. They were the first bass reflex cabinets ever offered to the public when they were introduced back in 1937. Production lasted one year. In addition to being the original "Onken" cabinet, they are the foundation for all of the ported boxes ever made.

Hugh Knowles, chief engineer at Jensen, and formerly of McMurdo-Silver, is credited with coming up with this groundbreaking design. Intended for use with McMurdo-Silver’s Masterpiece V radio receiver, the cabinets included an 18" full range Jensen field coil driver. This driver was essentially the same as the Western Electric TA-4181 and the Jensen V-18, M-18, etc. It used a special cone and a 4 ohm voice coil to allow HF extension well above the average 18" woofer. The advertised frequency response was 30 Hz to 9 KHz. An available option was twin 16 ohm Jensen Q8-P permanent magnet tweeters to extend the range above 15KHz. (It should be noted that Jensen marketed the Q8-P as a high frequency driver while the field coil Q4 used by EH Scott was marketed as a midrange driver.) The secret to the bass extension was a rear panel with 4 cutouts (ports); one at each corner. The four openings were to be equal in size but the opening on the lower right was sized larger. The power supply added the additional blocking at this location to make all 4 more or less the same size. It was the first radio cabinet designed taking into account the rear wave. Until then, cabinet design ignored the inherent cancelling effect of the rear wave. It was introduced in January 1937 during the production of the Masterpiece V; some V models have the "magic" rear panel, others do not.

The resulting sound is absolutely amazing. I generally use them with 10W 6B4G amps to great effect. They have a large, effortless presentation and the tweeters play well above my hearing limit. They have wonderful speed, especially considering the size of the cones. The sound quality is at the upper levels of what one might expect

This particular pair started as a Masterpiece V (1937) and a Masterpiece VI (1938). The VI has the back panel and the V does not. Both have the optional twin Jensen Q tweeters. Both cabinets are quite sound, especially in light of their age. They are in the condition as pictured; fair condition but structurally sound and restoreable. The color and finish do not match. It is probable, but not certain, that the finish of the V cabinet was stripped before I got it. McMurdo-Silver advertisements declare using black walnut for their cabinets so both may be the same underneath the finishes. Also included is a damaged but original piece of grill cloth in the event that the new owner wants to duplicate it. Both woofers have repairs to their cones but both cones are authentic, with original 4 ohm voice coils. The pedestal on the VI driver has some surface rust. The handle and pedestals are easily removed if one wants to paint or powder coat. The frames and magnet covers are cast aluminum so have no rust. The cast frame on the VI woofer is cracked at the lower left (viewed from the rear). It has been that way for a long time without affecting performance. I have included pics that show all damage. The field coils of the woofers were used as chokes in their respective power supplies and require different voltages for operation. This hasn’t been an issue – I use individual Kepco BHK regulated power supplies to energize the coils to the proper 24 watts. The supplies are not included but will be made available to the high bidder. Required voltages are: 125V @ .190A and 95V @ .250A. All 4 tweeters are original and excellent. The crossover network was originally a 1 or 2 uF paper cap located within the loudspeaker stand. These were dried out and removed long ago. I use 1 uF oil types and a pot currently. I have some NIB Jensen rheostats from the 30’s or 40’s that will be included to allow the new owner to make a more authentic network.

Local pickup is always welcome. I cannot quote any shipping charges until there is a winning destination. My best estimate is that I will have two crates of about 150 pounds each. Please check locally for what it may cost to get the two boxes from Richmond, VA 23222 USA to the destination. They will probably need to be airfreighted to any international locations but ground delivery can be arranged to US addresses. A packing charge of $150 for time and materials will be added to the total. This will defray some of the cost of making wooden shipping crates.

I do not accept Paypal. Most other payment forms are fine. This item, like many items on eBay, is subject to prior sale. The reserve price is below historic prices for pairs of Jensen 18" drivers.