Western Electric KS12027
- Thread starter Tsingtao_1903
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Solid vote here for building the TA-7331. 👍
Found on Instagram.
Sure am curious about those 12" drivers. Anyone?
He showed the inside view of some of his other projects and he was using GPA 414’s.
The P12N is a very good choice. But you should also consider A12 FC if you don't mind a power supply.. P12N has much detail, as it has a powerful alnico magnet There are other excellent P12's. We chose Jensen P15"R" for use in Iconic system.
Could give the link of A12 FC woofer ?
Photo is an example grabbed online...
For those interested in going all paper, early style, Jensen 12" woofers are good. While Jensen did not publish the A12 model in their catalogs, for all practical purposes, the F12 is the non-OEM model that Jensen sold directly with similar specs. The A12 FC woofer is an example of this.
Most A12s operate on high voltage, typically 180V or more, and were designed to draw power from the Hammond or Webster-built 6L6 and 2A3 PPP amps that they often accompanied in early 1950s tone cabinets. These speakers are more "wide range" than strictly a woofer, similar to Joe Roberts's writings on the magic of the WE728. Nonetheless, they perform well as woofers (within limits) and were used in tone cabinets due to their ability to produce very nice mids with a few highs and a smooth roll-off, while still delivering some natural bass -- not needing any help from horns etc. Hammond probably also used electronic filtering to further shape the tone for pipe organ. These speakers were perfect for the old open-backed solid wood cabinets of the day.
The A12 was produced in large quantities well into the mid-1950s, well past the time when field coil speakers were thought to be obsolete. The cooler units even have pedestals like the highly valued Jensen "M" series used by WE in the ERPI days.
Some Jensen A12s have a fabric damper/spider, while older units have the old-style phenolic suspension. The latter is expected to give it even more speed and midrange potential.
The catalog page belows, shows the "F12" -- it's basically the same.
Early @ HiFiTown
Attachments
KS-12027 is a small horn responsible for 1000-15000 Hz used in WE-757A.
The WE-728B is a full-range 12-inch woofer with poor bass ability, but like the WE-755, it is 4 ohm. So, when I saw that design, I thought the KS-12027 was a virtual coaxial for the main purpose of connecting two 4-ohm woofers in parallel. In general, the lower the ohm, the rougher the sound, so if you can get a 12-inch woofer of the same standard, connect it in series to make an 8-ohm woofer, and make the 1-inch compression driver for KS-12027 in the middle operate up to 20K at 8 ohm. I believe it will work quite well. However, the crossover is newly designed and the recommended compression driver is JBL D220ti. My idea is to keep only KS-12027 without using WE units.
The WE-728B is a full-range 12-inch woofer with poor bass ability, but like the WE-755, it is 4 ohm. So, when I saw that design, I thought the KS-12027 was a virtual coaxial for the main purpose of connecting two 4-ohm woofers in parallel. In general, the lower the ohm, the rougher the sound, so if you can get a 12-inch woofer of the same standard, connect it in series to make an 8-ohm woofer, and make the 1-inch compression driver for KS-12027 in the middle operate up to 20K at 8 ohm. I believe it will work quite well. However, the crossover is newly designed and the recommended compression driver is JBL D220ti. My idea is to keep only KS-12027 without using WE units.
