EMI TG Console

EMI TG Consoles Under Construction
EMI factory in Hayes, Middlesex, (West London) in the early 1970's.

Mr. Gibson was kind enough to forward us very detailed information on these desks. Thank you very much.

Brian Gibson recently left Abbey Road Studios in London after 30 years working in the maintenance department and now works on a freelance basis. During the time he was at Abbey Road he was responsible for installing and maintaining several of these consoles, and still maintains a couple as part of his freelance work.

These are the Mark III evolution of the desk. In the foreground is a 24 input/ 16 group desk. The unit on the trolley to the upper left is the stabilised power supply, whilst on the floor in the right foreground is an individual channel module. The desk to the rear is the same sized frame but with only eight output groups fitted. These consoles were never produced commercially, but were manufactured for use in EMI recording facilities world-wide. In addition Abbey Road Studios in London, countries included France (Pathe-Marconi), Germany (Electrola), The Netherlands (Bovema) and several other European countries, Nigeria, South Africa, Hong Kong, Singapore, Australia and New Zealand. I have been trying establish the production numbers but due to company restructuring the records appear to have been lost.

The EMI TG Mixing Console

The EMI TG12345 Mixing console was produced by EMI Research Laboratories, Hayes, to a design brief submitted by Abbey Road Studios. The design was for a Transistorised ("Solid State") multi-channel mixing console to replace the 10in/4out valve (vacuum tube) mixers which had been in use at the studios since the 1950's.

Part of 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 multi-track session.

A specification for the console was drafted in December 1967.
Since at this time EMI manufactured its own recording equipment there would be a limited production run of these consoles to equip its various studios both in Europe and the far east. The console was of a “split” design, with separate faders for microphone gain and group output level, along with separate rotary monitor level controls for each track.

The main points which differ on the TG consoles compared to more recent designs are outlined as follows:

1. Operating Line level was 0dB = 0.447 volts. This is a legacy of EMI's earlier consoles which worked at an operating impedance of 200 ohms, as opposed to the US operating impedance of 600 ohms. 0dB Line level in a 600 ohm system is 0.775 volts (1 milliwatt) with the usual operating level being +4 dBm which is 1.228 volts. The TG operating level is 0 dB into 200 ohms, which is 0.447 volts. This is 8.8 dB lower than +4 dBm (usually rounded up to a nominal 9 dB)

2. All inputs and outputs are balanced using transformers.

3. There is no integral patchbay and no internal insertion or patching points.

4. Every channel is fitted with an integral Limiter/Compressor (A world first?)

5. Almost every rotary control is a stud switch, with precise calibration for repeatability and matching.

6. Each modular section ("Cassette") was dual channel containing identical left and right signal paths.

7. Each Cassette contained its own local DC power supply, with its own rectification, regulation and decoupling. The 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 local to the channel meant that much smaller decoupling capacitors could be used rather than the massive decoupling necessary on a remote DC power feed. A heavy gauge earth loom was supplied to link all the individual cassettes and the frame together, and provide a low impedance ground return path.

Item 1 above makes it slightly awkward to use these consoles with modern recording equipment operating at +4 dBm line levels. Although most tape machines have sufficient gain in hand to allow for adjustment, other equipment sometimes needs a +9 dB buffer amp on the send and a simple resistive attenuator on the return.

EVOLUTION and DEVELOPMENT

The TG series of mixing consoles evolved through several different versions.

Mk I
This was the original spec. version as supplied to Abbey Road. It was only produced as a 24 mic. 8 track (group output) + Aux stereo configuration. Basic EQ.(Bass & Treble on Mic channels). It also featured a stereo "spreader" (width control) which could be switched in on the Mic. channels. Finished in light grey paint on panels with a dark grey hammer finish frame.

Mk II
This was still produced in a 24/8 format but with modified EQ. The HF equaliser on the Mic. channels was thought to be too limited in its operation. Abbey Road enginers requested a presence control as fitted to the Group channel be fitted to the Mic. channels. An improved limiter/compressor was fitted, along with various minor refinements such as multi-track announce instead of the individual track buttons of the Mk I. Abbey Road examples had dark grey front panels and the dark grey hammer finish console frame was dressed up with wooden end cheeks.

Mk III
Final production version of the TG console as supplied to overseas studios, but never used at Abbey Road. This was a 16 track version of the desk. In order to minimise the frame size, the Group channels and the track monitor ("TMC") cassettes were eliminated. The monitor controls were moved to the area of the main cassettes previously occupied by the Aux Stereo controls. To overcome the Line level problem an optional line booster amplifier was produced with this series of consoles, which raised the operating level to the more common +4dBm.

Mark 4/ "Mark Q" (Unofficial designations)
Only two consoles of this specification were produced both of which were installed at Abbey Road (originally in Studios 2 & 3, later the desk from 3 was transferred to Studio 1). The Mark Q designation came from the provision to monitor "Quadrophonic" 4 channel surround sound, with the addition of front/back pan controls on the monitor channels and the incorporation of encoder/decoder switching on the Control Room Monitor cassette, allowing the effects of the "SQ" processing system to be monitored. The Main and Group channels were eliminated completely and Mic. cassettes from the Mk III were used throughout the desk, supplemented by specially made "auxiliary" Mic. and Main cassettes. The frame also housed a simple 16 channel "sync mixer" to mix the sync playback signals from the tape machine and feed them to the cue (foldback) 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 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 studio 2, by an SSL 4000E series console in 1983.

The "Mark 4" mixer was housed in a wooden console housing 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 and was much better suited to a fixed studio environment.

The earlier mark I and mark II desks became used exclusively as mobile desks at Abbey Road. Since their mechanical construction was too flimsy to withstand continual mobile use, the cableforms were split and fitted with mating connectors whilst the frames were rebuilt in sections constructed of tubular steel which were much stronger than the originals. These 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 cableforms would be plugged together and the desk would be ready for use. These modifications were all carried out by Abbey Road engineers There was even a 16 track version built from two 8 track frames, although the desk featured two Control Room Monitor cassettes and it was necessary to operate two line in/line out keys simultaneously when switching from record to replay.

Although the only Beatles album recorded using the TG desk was “Abbey Road” many significant records of the early seventies through to 1983 were recorded on them, notably Pink Floyds “Dark Side of the Moon” and some of the early Paul McCartney “Wings” albums.

Several of the Ex-Abbey road consoles still exist, most in working order. One of the “Mark 4” consoles is owned by producer Mike Hedges (Texas, Manic Street Preachers, Travis & others) and is installed in his private studio in France. Mike also owns two ex-Abbey Road mobile desks. Another mobile desk is also privately owned and used in a programming studio, although it was also used for the remastering of the Beatles “Anthology” albums, when it was re-installed at Abbey Road at the request of engineer Geoff Emerick. (Incidentally, temporarily replacing a Neve “Capricorn” digital console!) This particular desk has been advertised for sale (without success) recently.

Other complete desks of this type I know of are Mark III versions, again in private studios. One was returned to England from Sydney Australia, where it was originally installed in EMI Studios 301 in Sydney. This desk was recently used in the recording of the Oasis album “Standing on the shoulders of giants” and there are photos of it on the cover of the album. The other belongs to a producer songwriter who works with Tina Turner, and parts of her last album were recorded using it. This particular desk came from the EMI Pathe Marconi studios in Paris, where it was used in the seventies to record two Rolling Stones albums, so it has quite a history.

Brian Gibson, February 2001

See www.tgmixers.co.uk for an expanded history and more, of the EMI TG 12345 console.

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