For purchase, a gorgeous pair of ESS Heil amt 4 ohm woofers. The surrounds were just replaced with open cell polyether foam in June 2023, and the bextrene cones are very clean. As most early ESS builds, these woofers have 2 voice coils wound on anodized aluminum formers. Resistance measurements are 3.4 and 3.3 ohms, respectively. They should be considered an essential replacement if your woofers are indeed compromised. Utilized in several models of amt1(x), these are drop-in ready for models such as amt1a, 1b, 1c, amt1am, amt monitor, and all bookshelf variants of those models. These are factory original bextrene 12 drivers by ESS of Sacramento, removed from amt1b loudspeakers. These drivers are optimized for the specific dividing networks and cabinet offerings that were available during the production years of amt1b and monitor tower builds, circa 1977 through 1980. Modern replacements (from ESS currently) are not engineered to be coupled with amt drivers, nor your existing crossover networks where applicable. No testing or sampling has been performed with the new, generic off the shelf woofer drivers provided by the new Los Angeles based ESS. Packing will be very stout, expect these to arrive as advertised. UPS or FedEx will be the carrier, please let me know if you have a shipper preference. As with all of my listings of ESS equipment, if you are looking for parts from that era of long gone builds, feel free to inquire as i will assist with whatever parts i may have inventory of. I usually ship within 48 hrs of completed payment. Thank you for looking.

For purchase is a pair of original 4ohm ESS amt tweeter diaphragms of the Kapton variety. ESS has not made Kapton diaphragms available for a very long time. This diaphragm pair has unique power and heat handling characteristics due to its membrane substrate material. Transparent goldish in color, these have been gently used, are extremely rare, and come with no restrictive netting. These 689-1107 membranes fit all of the larger amt tweeters, including amt1a / 1b / 1c / 1d / amt monitor / amt1am, and all of their bookshelf variants. Due to this pair being of the 4ohm variety, they would not be appropriate for early ESS builds such as the amt1a, which use a dividing network designed for 6 ohm membranes. Kapton membranes allow for a longer life span due to their higher heat handling, at full rated power input. Original Heil air motion diaphragms from ESS of Sacramento. I typically ship within 36 hrs of completed payment. Thank you for looking.