EMT Plate Reverb Tech Support and Audio Samples
updated 10th November 2012 by Eddie Ciletti
Over the past year, I have been helping a client get his EMT 140 Plate
Reveb online. It started back in August 2011 with an amplifier overhaul.
I added a few EQ trim mods in anticipation of instaling new piezo pickups
that will have higher output and much more low frequency response.
The new pickups were installed a few months later by my assistant at the
time, John Kargol. In October 2012, the plate was tuned (re-tensioned)
as per Jim Cunningham's specs and 'calibration' tools. Then, the
driver magnet assemble was repositioned because EITHER the plate had been
mistuned for a long time OR the frame had been bent, because the voice
coil was runbbing agains the magnet assembly.
The first week of Novemebr 2012, I added a 12 dB / octave high pass
filter to eliminate sub sonic interference. While it was a bit difficult
to predict how the passive filter would affect the piezo - the filter itself
reduce the level at 160Hz by 6db. It's a little more complicated
than that and I will share the details ina fture update. I
think you will find that the initial listening tests confirm that my educated
guess was in the ballpark.
Thanks to Zach Hollander at THE
PEARL RECORDING STUDIO in NE Minneapolis for sending these sound samples...
You'll want to purchase Jim
Cunningham's tuning kit. Jim worked with Bill Putnam at Universal
- the Studios and the Audio company - and, when the EMT plate patent expired,
he created his own Echoplate Versions. He is knowledgeable, helpful
and has an extensive audio history.
Folow Jim's instructions and do not overtighten. The plate may seem
'loose,' especially across its length.
Amplifier upgrade include replacing interstage and power supply capacitors
and upgrading plate and grid resistors to metal film. I also replaced
the filament hum balance pots.