The Hammond M-100 was smaller than the classic
B3 model, and is one of the smaller "spinet" organs. The Spinet organs
are related to the larger B3 and C3, but have shorter keyboards, built-in
amplifiers, and fewer pedal options. These small Hammonds are more portable,
and were used by many famous groups: Procol Harum's "Whiter Shade of Pale"
(M-100), Booker T and the MG's "Green Onions" (M3), and early Pink Floyd
(L-100). The spinet Hammonds generate sounds by mechanical "tonewheels"
spinning inside the organ -- just like the B3/C3 series of organs. While
other organ companies used electronic oscillators or vibrating reeds to
create notes, the Hammond tonewheel system creates a warm, rich sound
that has become the classic organ sound of the '60s and '70s.
John Paul Jones used his own M-100 for the first
Led Zeppelin record, on "You Shook Me" and "Your Time Is Gonna Come."
The M-100 is featured on the "You Shook Me" solo beginning at
2:07. The most interesting aspect of this track is the lack of a Leslie
speaker; considered standard practice for Hammond recording, the Leslie
speaker adds a spinning effect to the organ tone. Instead of a Leslie,
Jones used the M-100's built-in Vibrato setting and, throughout the solo,
he changes the Vibrato/Chorus rate and depth, which effectively creates
a similar sound to the Leslie. The M-100's Vibrato/Chorus tone shares
the same circuitry as the larger B3 and C3, so it is slightly superior
to many other spinet models (like the L-100).