⭕ A unique opportunity to purchase these ultra-rare (circa. 1955) Decca Domestic Corner Horn Speakers (serial nos.22.. and 24..) loaded with very early Metal PlaquePM7As (serial nos.22.. and 22..).The enclosures are in superb condition (especially considering they are over 55 years old) and have the original piano-laquer finish.They sound and look simply awesome.
The Lowther PM7As (with almost consecutive serial nos.) possess massively high-gauss,pure Alnico, magnets.I have owned PM6As and PM2As but these sounded hard and a little compressed in comparison.As far as I am aware the PM7A was constructed using much higher quality magnet material(shared by the mighty PM4A)and therefore the PM7A is truly high-end in performance and quality.These particular drivers have been totally refurbished by way of addition of brand new Lowther manufactured:
Cones
Surrounds
Spiders
Baskets
Adaptors
Gaskets
Hardware (bolts,washers,etc)
All the above are genuine Lowtheritems and have consecutive serial numbers 13370 and 13371.The original Lowther packaging has been retained for completeness.These units (if looked after) will provide many,many years of listening pleasure.Since the service (carried out 17th May 2012) they have had less than one hours use and are not even run-in (suggest circa.40hrs use) and are quite literally plug and play.The magnets are totally original and work perfectly providing awesome dynamics,presence and startling realism.
Specification is as follows:
DC Resistance of Voice Coil Re 7.4 ohms
Free Air Resonance Fo 64.609 Hz
Emission Piston Area Sd 0.021
Equivalent Volume Suspension Vas 43.429 Ltrs
Suspension Compliance Cms 693.505 u M/N
Mass of Cone Mmd 7.0 g
Mass of Moving Parts Mms 8.75 g
Force Factor Bl 8.234 T-M
Mechanical Q Factor Qms 1.751
Electrical Q Factor Qes 0.338
Total Q Factor Qts 0.317
Voice Coil Inductance 1 kHz Le 102.389 uH
Reference Efficiency No 2.922%
Sound Pressure Level SPL 96.674 Db