|Speaker||12" Jensen Alnico PM P12Q|
The 115 was the model number for the Lyric. The Lyric, along with the Maestro, were the premium amplifiers in the Magnatone stable. It has two input channels, each with its own volume control and a shared treble and bass control.
Nathan Hellman was vice president and head of engineering during this era. Sometime in 1953 the M-19x model designations were replaced with models numbered in "100's". The 115 replaced a M-192-6 designation, and was only produced for a short while (maybe to sometime in 1955, mostlikely being replaced by the 150, 160, and 180's).
Above is an early example (est.1953-54). The Chrome emblems were used for a short time around 1953 and the speaker baffle-board loads from the back. Compare that to the examples below. Both are front loaded baffle-board cabinets. The amp at left has the round emblem from 1954. The amp pictured center and right is from 1955-56.
On at least one later 115 I came across, there was an unused octal socket near the pre-amp 12AX7. I'm not sure what this was used for originally. pin out was #1 ground; #2 and #7 heaters; #3 B+; #5 B+ ?? ; and #4,6,8 not connected. Please email if you have any ideas about this extra socket.