One of the
most famous, legendary and musically inspiring was the TG
12345 series EMI recording\mixing desk. The technical design
was carried out by the EMI Studios technical department for
studio's equipment development.
The EMI TG12345 Mixing console was produced by EMI Research
Laboratories, Hayes, to a design brief submitted by the
engineers at Abbey Road Studios. The requirement was for a
Transistorized ("Solid State") 24 channel, 8-track mixing
console to replace the 10input/4-track valve (tube) mixers
which had been in use at the studios since the early1960's.
the original design brief was for the desk to be
"transportable," (as opposed to portable), so that it could
be used for location recording, and also the ability to make
a simultaneous stereo recording at the same time as a
specification for the console was drafted in December 1967,
and a prototype was delivered to Abbey Road in the fall of
1968 and installed in Studio 2 in December.
this time EMI manufactured it's own recording equipment,
there would be a limited production of these consoles to
equip it's various studios in Europe, Africa, South America
and the Far East.
The construction featured all discrete components and a
novel motherboard/daughterboard interconnection between the
circuit sub- assemblies.
Technical features of the TG
12345 Recording\Mixing Console
The TG consoles featured the
following technical innovations:
Limiter/Compressor on every microphone channel (A first on a
inputs and outputs were balanced using transformers.
Almost every rotary control is a stud switch, with precise
calibration for repeatability and matching.
modular section ("Cassette") was dual channel, containing
identical left and right signal paths. These could be used
as a stereo pair, or two independent mono channels.
Cassette contained its own local DC power supply, with its
own rectification, regulation and decoupling.
mixer "Power Unit" was simply a constant voltage
transformer, which supplied 50 volts ac to a wiring loom,
which fed all the power supplies on the individual
cassettes. Keeping the power regulation within the channel
meant that much smaller local decoupling capacitors could be
used rather than the massive decoupling necessary on a
remote DC power supply.
EVOLUTION of the EMI TG 12345
The TG series
of mixing consoles evolved through several different
the original spec. version as supplied to Abbey Road. It was
only produced as a 24 mic. 8 track + Aux stereo*
configuration. Basic EQ. (Bass & Treble on Mic channels,
with Presence Controls on the Main and Sub-Groups). It also
featured a stereo "spreader" (width control) which could be
switched in on the Mic. channels. Finished with light grey
front panels, with a blue hammer finish main frame.
Stereo was a feature of the earlier desks. Intended for use
in a "live" situation, it was simply a method of deriving a
simultaneous stereo mix from a multi-track recording. There
were individual level and pan controls on the eight main
output buses and by using these a separate stereo sub-mix
could be created. This is why the MkII consoles pictured
have ten group faders and meters, the extra pair being the
masters for the Aux. Stereo bus. Aux Stereo was not
extensively used, and was a feature that was deleted on the
later MkIII and Mk4 consoles.
still produced in a 24/8 + Aux stereo format, but with
modified EQ, and various minor refinements, such as
multi-track announce, instead of the individual track
buttons of the Mk I.
simple "shelving" HF equaliser on the Mic. channels was
thought to be too basic in operation, and the Abbey Road
engineers requested a presence control, as fitted to the
Main and Group channels, be fitted to the Mic. channels. The
Limiter-Compressor was improved and the spreader control
Road also requested a colour change, to dark grey, for the
front panels, and the dark grey hammer finish console frame
was dressed up with wooden end cheeks.
The two front panel colours were offered as an option, with
the result that some overseas versions were supplied with
light grey front panels and others dark grey.
console was further developed by EMI Research Laboratories
into the Mk 3 version. This final production version of the
TG console was supplied to overseas studios, but never used
at Abbey Road.
basic version of the Mk 3 was a 24 input, 16 track version
of the desk, although the frame was produced in various
sizes up to 32 input, 16 track. In order to minimise the
frame size, the track monitor ("TMC") and Group cassettes
were eliminated, although the Group cassettes could still be
fitted as an option. The monitor controls (pan, level & echo
send) were moved to the area of the main cassettes
previously occupied by the Aux Stereo controls. Minor
changes to the Cue/Foldback controls.
dedicated "Echo" cassette was introduced, each of which
contained the master level controls and Eq. for two sends,
plus a pair of echo returns.
Mark IV / "Mark Q"
Mk 4 consoles were produced, both of which were custom built
for Abbey Road (originally in Studios 2 & 3, later the desk
from 3 was transferred to Studio 1).
Initially they were built with a combination of Mk II and Mk
III cassettes, but they were later upgraded to what was
unofficially called the Mark Q.
The Mark Q designation came from the provision to monitor
"Quadraphonic" 4- channel surround sound, with the addition
of front/back pan controls on the track monitor cassettes,
and the incorporation of encoder/decoder switching on the
Control Room Monitor cassette, allowing the effects of the
"SQ" processing system to be monitored.
and Group channels were eliminated completely and Mic.
cassettes from the Mk III were used throughout the desk,
supplemented by custom made "auxiliary" Mic. and Main
cassettes. The Mk3 Echo Cassettes were also incorporated.
The frame also housed a simple 16 channel "sync mixer" to
mix the sync replay signals from the tape machine and feed
them to the cue (fold back) circuits. Although the basic
configuration was 24/16 the possibility of using Mics on the
main channel inputs meant it was theoretically possible to
have up to 40 mics with 16 group outputs. The flexibility of
the configuration also meant that some mic. channels could
be used as monitors for tape returns allowing for 24 track
operation, and still have up to 32 microphone inputs
available. It was this flexibility which allowed the desk to
be used well into the 24 track era before it was finally
replaced in Abbey Road studio 2, by an SSL 4000E series
console in 1983.
4 mixer was housed in a substantial wooden console which had
a semi-wrap around layout, with the outer wings of the frame
angled back towards the operator for easier access. The
whole console was a much sturdier construction than the
previous versions, and was much better suited to a fixed
was another official Mark "Q" version produced for the Pathe-Marconi
studios in Paris. This console had full Left-Right &
Front-Back pan controls fitted to every channel.
Housed in a frame based on the TG post-production console,
the "quad"modifications meant that Limiter/Compressors were
not fitted due to lack of space. This console is now owned
by "Vega" studios, in Southern France.
earlier Mk I and Mk II desks were modified by Abbey Road
technical staff to become used mainly as mobile desks at
Abbey Road, although one was used in a dedicated remix room,
and was later modified for 4 channel "Quadraphonic" mixing.
having been designed from the outset for "transportable"
operation, their aluminum frames were inadequate to
withstand continual mobile use. As a result the Abbey Road
engineers modified the construction of the consoles. The
cable forms were split and fitted with mating connectors,
whilst the frames were rebuilt in sections constructed of
welded tubular steel. The frames were fitted with lockable
castors, which made transporting them much easier. Once on
location the sections of the frame could be wheeled together
and secured, then the cable forms would be plugged together
and the desk would be ready for use.
modified frames were built in various configurations to suit
different recording requirements.
was even a 16 track version built from two 8 track Mk II
desks, with full Four Channel ("Quadraphonic") surround
The following Studios
currently operate or own TG consoles:
2 KHz Studios,
Abbey Road Studios, London.
AR Studios, Rio de Janiero, Brazil.
Vega Studios, France.
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