Revox B77 Tape Recorder is the industry standard. A well-designed tape transport mechanism will
not distort mechanically. It is insensitive to shocks and vibrations and will retain these qualities over a wide range of
temperatures. Therefore, REVOX B77 tape recorders use die cast parts for the motor chassis, the side bearers, the cross
member and for the head block and the pinch roller arm. This ensures exceptional stability for the precision tape guiding
system and the sound heads, as well as for the motors and the brake assembly. The motors are sturdy AC asynchronous
types - unbeatable in simplicity and reliability - thus especially suited for heavy-duty use.
Direct drive capstan motor with tacho generator and servo electronics to ensure outstanding speed stability independent
of variations in load or changes in the electrical supply voltage or frequency.
Magnetic tape recorders are an outstanding example of the perfect combination of precision mechanics and top performing
electronics. Even the best electronic circuitry would soon become worthless if the original precision in tape guiding is lost
as a result of insufficient long-term stability. One of the basic requirements therefore, was to ensure Revox B77 stable performance
for years, achieved with a rigid mechanical design, which disregards the possible advantages that may lie in such tempting
advertising claims as "feather weight" and "slim line"!
Precision cannot be realized without ruggedness. This is the reason why all important parts of the B77 transport mechanism
are made from solid die-castings.
Speed control via servo electronics
In 1967 STUDER REVOX had already ushered in the age of electronic capstan speed control for domestic tape recorders. Ever since then many have tried to copy it, yet they have never been able to match its simplicity and effectiveness.
The principle of electronically regulating a sturdy asynchronous motor by means of a separate precision reference has stood
the test so well that it has been adopted for the STUDER professional tape recorders years ago. The capstan motor and its
precision reference combined with the inductive speed sensor and its control circuits form a regulating loop, which is highly
insensitive to variations in power line voltage and frequency or changes in load. This system, which has proven its reliability
in more than half a million tape drives, combined with ideal tape guiding results in outstanding motion stability (freedom from
wow and flutter), which remains unchanged for years. The remarkable mechanical and electronic stability of the complete
tape transport mechanism makes it well suited for mobile operation by Revocx B77 powering it from car batteries in conjunction with
an inverter. For pitch matching or to achieve special effects, motor speed can also be varied continuously over a wide
range with the help of an external speed control.
The Revodur all metal heads for recording and playback, the erase head, the infrared tape sensor and the tape guides; all
these components are mounted on a rigid die-cast frame. A fourth magnetic head can be fitted to record automatic slide
synchronizing control signals (DIA/DHA/FH). These signals are recorded within the guard band of the tape allowing their
use with normal stereo signals.
As far as development of magnetic sound heads is concerned, STUDER REVOX is looking back on an experience which
equals that of building tape recorders.
Our experts manufacture all metal heads for REVOX B77 tape recorders and for professional sound recorders. The special
alloy Revodur ensures excellent magnetic properties and outstanding wear characteristics. The shape of the head's face
is designed to ensure a "ruler flat" response down to the lowest audio frequencies.
Ease of editing
The practical edit facility is standard equipment on each Revox B77 recorder.
By operating the sliding button, the tape is brought into contact with the heads, the playback amplifiers become activated
and the fast wind buttons respond only as long as they are held depressed.
This facilitates motor assisted searching for the edit point while final tape positioning is then performed manually.
The thoughtful design of the lower control panel facilitates easy access to tape heads for accurate tape marking. An
ingenuously conceived edit mode facilitates motor assisted tape shuttling and final manual locating of the exact edit point.
Part of the B77 head block, showing the roller bearing tape guide and infra red tape end detector.
The integrated tape cutter helps to make editing a simple task.
Half track (S2):
Half track models are always selected when tape splicing (editing) is required. Because of the large track width of 2mm,
these models feature excellent ratings with respect to frequency response and treble dynamic range.
The half track version can be equipped with slide control electronics and an additional sound head.
The high-speed version of the half track machine is ideally suited for applications requiring maximum audio quality
(e.g. as effects machine in audio or film production).
The quarter track (S4):
The advantage of quarter track machines over half track machines is the double tape capacity.
The quarter track B77 is suited for applications where long playing times (up to six hours on the standard speed B77)
combined with excellent audio quality is essential.
The quarter track machines can also be equipped with side control electronics and an additional sound head.
Because of the narrower track width, the audio specifications are in certain areas slightly inferior to those of half track
The quarter track configuration interleaves the two stereo tracks. This allows the reels to be "turned over" allowing
double the recording time
The half track configuration uses the full width of the tape to lay down a stereo image. (excluding the guard band)
Standard version of B77
Speed, 3.75 and 7.5 ips:
The REVOX B77 has been designed to satisfy the requirements of a vast number of applications.
ALL machines are constructed from the standard speed version, without major changes to the electronic or mechanical
The flexibility of the B77, and its mature technology are two of the main reasons why the REVOX B77 is frequently used
by recording studios. Often side by side with the STUDER multi cannel studio tape machines.
The Revox B77 features an extremely stable 3 motor tape transport system, which can be adapted easily to individual applications.
The neat arrangement of the control and audio electronics ensures excellent access to various test points and trimmer
potentiometers for maintenance work, thus allowing field modifications to the machine for other applications.
ALL tape transport functions can be controlled remotely. A cable type remote control is available as an accessory.
Of course, the tape speed can be varied by an internal control (mk 2 decks) allowing +/- 10% or via an external control
across a wide range of 7 semitones.
Some of the simpler operations can also be performed by unskilled personnel because the controls are arranged for
maximum operating convenience and reliability.
The logically interlocked tape command keys as well as the record pre-selecting facility (protects against unintentional
erasure) also contribute to
high operating reliability. With its sophisticated transport and audio electronics the Revox B77 is a flexible and efficient tape
recorder with great application potential in recording, broadcasting, and film studios, as well as in industry.
The B77 standard speed version (3.75 and 7.5 ips (9.52 and 19.05 cm/s)) is available as a half track or quarter track
machine with NAB equalization.
Depending on the application, either a rugged plastic housing with Nextel coating or a metal housing (for cabinet mounting)
can be ordered.
High Speed version of B77
Speed, 7.5 and 15 ips:
The Revox B77 HS is ideal for applications that require maximum frequency response, dynamic range, and treble response.
Because of the high tape speed (7.5 and 15 ips (19.05 and 38.1 cm/s)), excellent frequency and treble response is
achieved. Editing and splicing is also easier and more accurate with high tape speeds.
The Revox B77 HS features the same sophisticated tape transport control as the standard speed model. The tape speed is
doubled by increasing the capstan shaft diameter and slightly re-positioning the capstan motor.
The B77 HS can of course be operated with the same accessories as the standard speed model.
The high speed version is particularly suited for semiprofessional use or as a cost effective alterative to expensive
studio machines in smaller recording studios or
local broadcasting stations. For this reason, the B77 HS is also available as a half track machine with either NAB
or IEC equalization. The type of equalization to be selected depends on the equalization standard of the existing
equipment or the library of recorded tapes being used.
The Revox B77 HS can also be fitted with an additional sound head for control purposes.
Low Speed version of B77
Speed, 1.875 and 3.75 ips:
The Revox B77 LS is designed for audio applications where uninterrupted playing times of over 6 hours is required and
with excellent reproduction.
The B77 LS operates at two speeds: 1.875 and 3.75 ips (4.76 and 9.52 cm/s). The main distinctions to the B77
standard model are the smaller capstan diameter and a corresponding lower capstan motor speed. The Revox B77 LS is
available as a half track or quarter track machine. Because of its high recording and reproduction quality the B77 LS
is ideal suited for audio applications in museums, exhibitions, galleries restaurants, or for speech recording during
Depending on the application, either the half track or quarter track machine can be selected. If only speech is to be
recorded, the quarter track version is recommended because the recording time is twice as long. For recording and reproducing music, the quarter track version is less suited. It has equalization according to NAB standards.
The Revox B77 LS is available in a Nextel coated plastic housing or in a metal housing (for cabinet mounting).