Thermionic Culture THE FREEBIRD 3 channel equalizer - Manual (Page 4)

©Thermionic Culture Ltd., May 2011 3
1 Introduction
The Freebird is one of a new line of products from
Thermionic Culture Ltd. These products all share the same
basic front panel size and casing design, which uses a half
rack 4U size and a detachable power supply. We have
selected this format specifically to increase the tactile feel of
the front panel controls and to allow us to create a modular
product range.
The Freebird offers three channels of all valve EQ. Each
channel has a transformer balanced input, a transformer-
less unbalanced output and uses two valves.
The input valve is a 5965 as found in our Fat Bustard
summing mixer. The output valve is a PC86. These valves
are run in a single ended configuration which, we feel, gives
a good balance between smoothness, clarity and harmonic
distortion.
The EQ circuit is an active design, part of which is derived
from a circuit created by Vic Keary in 1961. It was used in
several valve consoles which were used from the early
1960's until present. The circuit has been refined and
enhanced in order to make The Freebird as versatile as
possible.
We feel that having three channels available, will allow the
user to approach this equaliser as a multichannel type EQ,
rather than simply a traditional mono or stereo EQ. The
difference being that this can then be used in many
applications rather than permanently consigned to only the
mix bus or only lead vocal, for example.
The Freebird would do a great job in both applications at the
same time or in whichever combination the user desires.