|
In 1947, Brenell Engineering Ltd. were small, precision jobbing
engineers, based in Northington Street, Clerkenwell, London. They made simple optical toys and metal screw caps for, it is
believed, the photographic industry.
Founded by Czech refugee, Robert Hahn and Peter Glazer, who both served with the RAF during the
war, they were contracted in 1953 to design and build a tape deck for a new home-assembly tape recorder, the "Sound Master".
It is not yet clear how this came about, but Brenell also made under contract around this time a telephone answering machine
- of which little is known. It is perhaps ironic that the pioneer of tape recording, the Danish telephone engineer Valdemar
Poulsen, designed and patented his first machine to record telephone messages!
The "Sound Master" (left) was designed as a simple, yet
highly specified 3-motor, 2-head, 3-speed tape deck using the best available technology and components to which could
be added a valve pre-amplifier either underslung from the deck or as a separate uint. All the budding audiophile had to do
was invest 6/6d in a set of illustrated instruction sheets, then source the recommended components and set aside
a weekend to build this fine machine. At a cost of only £50 for a complete kit, it made a substantial saving over the contemporary
Ferrograph. The deck components could be bought direct from Brenell in kit form, or from selected radio shops, complete with
Collaro motors and "Wearite" heads.
As these were the days of "Meccano" kits, anyone competent with a spanner,
screwdriver and soldering iron was capable of assembling the "Sound Master". The instruction manual was expertly written and
remains today as one of the finest books on tape recording theory.
The deck was finished in a light grey metallic 'hammered enamel' paint
and could be fitted into a ready made case or a radiogram. It offered three speeds, with a top speed of 15 ips for
true hi-fi reproduction. Speeds were set by a two speed pulley and the use of a high speed capstan sleeve, giving
the user the option of high quality recordings or longer playing times. A simple printed time lapse plate beneath the spools
indicated available playing times. Mechanical controls and linkages were incredibly simple, but of an entirely sound
engineering standard.
The "Sound Master" was very well received by contemporary radio engineering
magazines, which encouraged their readers to modify, improve and experiment with tape recording and create special effects.
Even today, surviving machines still produce a fine quality of recording. Many hundreds were sold, prompting Brenell
to design and build an improved 7" version for themselves under the 'Brenell' name. An example is seen (below
left) of the Elpico 'Impresario' cabinet fitted tape-recorder with the Elpico AC60 pre-amp. Though clearly a Brenell
tape deck it carries the 'Elpico' badge on the tape counter plate.
Launched in 1956, "The Brenell" was a re-engineered 7" version of the "Sound
Master". It retained, in essence, the same deck, with redesigned ventilation louvres, linkages and Collaro motors
and Marriott heads but had the function controls re-arranged either side of the new two piece enamelled aluminum, kidney shaped head
covers. The speed selection was still the same, with the upper head cover now cut-away to allow the screw-on capstan sleeve
to be easily fitted or removed. It produced a very high standard of reproduction through a simple Brenell-Marriott amplifier.
It had a 4 watt output to the internal speaker, with separate bass and treble controls. "The Brenell" tape recorder
sold for 48 gns - it was soon replaced by an improved Mk.2 version ( above right ), fitted
into the same attractive crimson 'Rexine' covered cabinet but now with Brenell's own Mullard based Mk.II amplifier.
The heads were now of Brenell's own manufacture - Brenell even supplied these to Collaro!
The Brenell's pre-amplifier control panel was set at a slight angle to the deck; setting the
style for future Brenell tape recorders. It was also available as a pure transport deck to which the Brenell pre-amplifier
and power supply could be added. This made it a popular choice among radiogram manufacturers, both at home and abroad.
In late 1957, a much improved model, the 8-1/4" Brenell Mk.IV appeared together with an optional
and much improved alternative Pre-Amp (see bottom of page) which incorporated a head de-magnetiser circuit and a
new frequency equalisation compensation control for each of the three speeds which, unlike the Ferrograph, could be changed
at will to compensate for different tapes and conditions. It also appears that the 7" Mk.2 may have been marketed in America
alongside the later Mk.5, but as a "Mk.IV", as America showed no interest in the 8-1/4" spool size. This probably made
the Mk.2 a most appealing budget model! Can anyone throw further light on that anomaly?
The new Brenell Mk.IV ( left ) for the home market, was
developed from the 7" Mk.2. Though it shared the same deck plate, it differed in many ways. The motors were now from
British Thompson-Houston with its spool motors set further back to accomodate the larger 8-1/4" spools (later spool
turntables had screw-in retainers). The heads were still of Brenell's own manufacture and were still screwed directly
to the now 'gold' hammered enamel deck plate, but there was now provision for up to four heads allowing for a variety of special
applications, including "staggered stereo".
New, extended kidney shaped, ivory coloured plastic head covers were
now fitted; these hid two studs on which were stored a 1" dia and 1/2" dia brass capstan sleeve when not in use; for while
the Mk.2 required the drive belt between the drive motor and capstan flywheel to be raised or lowered for the two speed ranges,
the Mk.IV had its speed changed by sleeves: thus directly off the capstan spindle for 3-3/4" ips; a 1/2" screw on sleeve
for 7-1/2 ips and a 1" sleeve for 15ips.
Whereas the Mk.2 had the record function controlled by the pre-amplifier, the Mk.IV was fitted
with a detent button on the new Record-Stop-Play motion control. It also had much improved control linkages, brakes and a
new sprung tape tension control arm on the take up side.
Whereas the Mk.IV tape recorder, (later called the Mk.4), with its splendid striped
yellow/brown cabinet offered basic facilities, the Mk.IV deck was also offered with a variety of options to suit the enthusiast,
professional and industry. In addition to the standard lapsed time plate, there was an optional tape counter,
fitted above the fast forward/reverse control, belt driven from the feed motor turntable. A special Mk.4 Model
600 ( right ) was fitted with an underslung pre-amplifier for console mounting and came complete with a central
'magic eye' recording level meter with a gain control and optional frequency compensation correction control; these were mounted
below the head covers and fitted with minature radio knobs (later with new black castellated plastic knobs). The
machine shown here was used by a Cambridge pathology laboratory!
With its superior motors and heavier flywheel, the Mk.4 boasted an impressive 0.05% wow and flutter
at 15 ips and 50-16,000 Hz for hi-fi performance. The Mk.4 sold well and soon established Brenell as a serious challenger
to Ferrograph in the semi-professional field.
Soon after the launch of the Mk.IV came an entirely new, purely domestic
model, the 7" Brenell "3-Star" ( left ). Was this the Mk.3 by another name?! Unlike other Brenells,
this was to be their only single motor design. Idler drive from a new alloy bodied BT-H motor powered the heavy capstan
flywheel while belts provided fast forward and rewind. Speed selection was by rotation of a cammed spindle set behind
the large head cover, giving three speeds on demand of 1-7/8, 3-3/4 and 7-1/2 ips. There were no additional capstan sleeves.
To make it even more fool proof, it used piano key controls set centrally in the large, chocolate brown head cover.
This was a strictly domestic model, but with 0.2% w&f at 7-1/2ips, frequency response up
to 14,000 Hz and a high quality speaker within a substantial plywood cabinet, it was more than adequate for domestic
hi-fi, added to which, its ease of use made it ideal for schools. Its stunning design gained for Brenell a coveted Design
Council Award.
It was later fitted with the new Papst motor (these had the rotary cabinet catches seen in the
photograph rather than the usual over-cam catch). With the popular move towards 1/4 track, it was also
offered with 1/4 track heads - it appears these may have been from "Miniflux" or "Wearite". Tracks were selected by push
buttons to the left of the head covers. In 1959 a special stereo model appeared. This was Brenell's first full stereo
(as opposed to 'staggered' stereo) and was fitted into a modified Mk.5 cabinet with two "3-Star" amplifiers (
below ) . Thus both stereo recordings and playing of commercially produced, exceptionally high quality stereo tapes
from HMV and Columbia was possible. It was however a short lived model.
With an impressive model range from the domestic 3-Star to the versatile
Mk.4, plus a new Mk.5 on the drawing board, Brenell soon found themselves desperately seeking additional accommodation. This
was found in nearby mews at Doughty Street.
In addition to the standard deck mounted pre-amplifier, with its 4
watt output stage to feed the internal 3ohm speaker (or external 15 ohm speaker) on their Mk.2 and Mk.IV recorders, Brenell
also offered an alternative pure pre-amplifier for connection to other hi-fi equipment. This unit (below left)
incorporated a head demagnetising circuit, frequency equalisation correction and a useful signal output mute facility
to avoid feedback during recording. It also used the new cathode ray recording level indicator rather than the usual EM34
'magic eye' . A revised version, called the TP.2, survived until
the advent of their STB based 'Tape Link' pre-amplifier.
With tape enthusiasts becoming more adventurous, tape recorder manufacturers began to offer simple mixers to, for example,
combine two microphones and a record player to create sound effects in a stage play. Brenell's own offering (right)
was a very basic, 3 into1 passive mixer which fed into the tape recorder's microphone socket. Initially in gold hammered
enamel they were still available in 1970, albeit in grey enamel.
|
