Model:77 mk III
Country of Manufacture:Australia
Max Reel Size("): 7"
Number of heads: 3
Head Composition: Permalloy
Head Configuration: Mono - Full Track
Frequency Response:(± 2dB): 50 - 10,000Hz at 7½ ips, 40 -15,000Hz at 15 ips
Wow and Flutter:better than 0.2% at 3¾ ips. 0.15% at 7½ ips. 0.12% at 15 ips
Signal-to-Noise Ratio:better than 50dB unweighted at normal recording level
Sound quality rating:5 / 10
Long-term reliability rating: 5 / 10
The Rola 77 Mk III replaced the Rola-produced
but Byer-badged 77 Mk II
in early 1962 and stayed in production up until the early 1970s.
Apart from several improvements in the deck construction, there were
three new features which made the machine more user-friendly and versatile.
Gone was the 4-position fast-wind “SHUTTLE CONTROL”. in its
place was a continuously variable winding control labelled “SPOOL”
which operated by applying current to the opposing spool motor to ‘brake’
it. An elapsed time indicator had been added whereby tape usage was indicated
on an analogue dial. One rotation equalled either 30 or 15 minutes depending
on whether 7½ ips or 15 ips was being used, with the smallest measurable
division being ten or five seconds respectively.
The third improvement was
a “FAST START” switch which switched on the capstan motor allowing
it to reachoperating speed before the transport was engaged prior to recording
The amplifier panel featured all of the functions that
were available on the Byer “77” Mk II, plus one additional feature
which, interestingly , had first appeared on the original Byer 77 but
had been dropped when the Mk II was released. This was a meter function
switch which permitted the VU meter to be switched from input display
to various internal voltages so that AC filament supply, DC HT, record
bias and cathode bias could be checked.
This recorder primarily saw service in schools, institutions,
armed forces and radio stations.
Sppoling: continuously variable, less than 1 minute for 1200ft / Inputs (all balanced): 50 ohm mic, 600 ohm line and 100 kohm bridging inputs. / Valve complement: 1 x 6GW8, 1 x 12AU7, 1 x 12AX7, 1 x 12BH7 and 4 x EF86 / Audio output power: 6 watts / Distortion: record – less than 2% from 600 ohm at +18dbm play – less than 2% for output level of +21 dbm / Speaker(s): internal oval ‘Rola’ speaker / Dimensions (approx): 19½ x 12¼ x 6½ inches (495 x 311 x 165mm) / Weight: 55 lbs (25 kg) / : / half-track mono