The Sony TC-K61 is
an outstanding expression of Sony’s ability to deliver the latest and best in
tape. The K61 provides the superlative speed constancy of Sony’s two-motor
drive system, controlled by a logic microprocessor IC. The microprocessor,
which receivers commands via feather-touch pushbuttons, executes them via
transport solenoids. The result is smoother operation, gresater flexibility,
and the capabilities for timer operation and remote control. Moreover, the K61
incorporates Sony’s exceptional Sendust and Ferrite record/play head, four-gap
erase head, LED Peak Program Meters, and a host of electronic refinements. Yet
for all its sophistication, the TC-K61 remains easy to operate - and reasonable
in price.
Low-Distortion
Electronics
Sony’s attention to
detail is evident in the electronic design of the TC-K61. For example, the
critical playback head amplifier uses a unique, patented, direct-coupled
design, which improves phases linearity and lowers distortion. The power supply
employs an FET-buffer circuit for constant-current drive, even when the
household voltage itself varies. And the K61 provides a switch for low and
normal Type Ibias, in addition to a four-position tape selector switch. Even
the selection of electronic parts reflects Sony’s commitment to the best
possible sound. The power supply incorporates fast-recovery diodes that
minimize noise. The equalization amplifier uses expensive metal film resistors
and polypropylene capacitors. Finally, the headphone/line output control uses a
stepped attenuator, with discrete, potted resistors for the lowest noise
possible.
Sony Dolby IC
A high-quality Dolby
noise reduction circuit typically requires about 100 separate parts, including
transistors, resistors, and capacitors. Sony has replaced all of these parts
with the newly developed Sony Dolby IC, the CX-174. Made with Sony’s unique “Process
V” wafering technique, the Dolby IC exhibits exceptionally pure chemical
composition. This helps the CX-174 realize lower distortion, wider dynamic
range, and better tracking linearity.
In addition,
conventional Dolby Circuits use a record/playback slide switch, which can
introduce noise. In contrast, the CX-174 works in conjunction with a relay
switch that is quieter and more reliable than the conventional slide switch. To further maintain
this recording accuracy, the TC-K61 incorporates a switchable multiplex filter.
When you record FM stereo broadcasts, the filter can be switched on to prevent
the standard 19 kHz FM pilot signal from interfering with the Dolby system. At
all other times, the filter can be defeated for optimum high-frequency
response
Microprocessor-Controlled
Transport
The sophisticated
two-motor transport is, in turn, controlled by a microprocessor IC logic
system. Feather touch pushbuttons provide convenient, foolproof mode selection.
You can go quiclky from one mode to another, without going through Stop. The
logic circuit checks each command for proper sequencing, and protects the tape
and mechanism from undue stress. The logic circuit also facilitates ‘Punch-in”
recording of new material onto a previously recorded track. End-of-side sensing
for All-mode Auto-Stop can be accomplished with Sony’s non contact Luminous
Sensor.
Two-Motor System
Because tape speed
irregularity can be heard as wavering sound, unvarying tape drive is essential
to high-fidelity cassette recording. For this reason, the Sony TC-K61 uses two
discrete DC motors to move the tape across the heads. This division of labor eliminates
any irregularities caused by variations in tape supply tension, and reduces the
number of mechanical linkages needed in the transport mechanism. The spooling
motor drives the reel hubs and provides fast winding. This high-torque motor
works in conjunction with the magnetic clutch assembly to provide not only
quick fast-forward and rewind, but also extremely gentle tape handling.
The second motor,
which drives the capstan, incorporates Sony’s famous brushless and slotless
(BSL) design for uncommonly even delivery of torque increases and decreases as
a result of spaces - “slot” - between the electromagnets. This wavering-force
effect is called “cogging”. Sony has eliminated cogging with the remarkable BSL
motor. There are no brushes, no slots, and the magnetic force is smooth and
constant. As an additional benefit, the absence of motor brushes makes the BSL
motor unusually quiet and trouble-free.
As with the TC-K44,
the K61 uses a frequency-generator (FG)servo system. In the K61, a tiny FG has
been incorporated into the BSL motor. As the motor turns, the generator
produces an AC signal whose frequency is proportional to the motor’s speed. In
this way, the FG reports any speed irregularities to the servo control
electronics, which in turn, governs the motor speed. Thus, even slight speed
variations are corrected - before they can affect the sound.
This advanced drive
system is completed by an oversize dynamically-balanced, anti-resonant
flyhweel. The die-cast, zinc flywheel incorporates a nonmetallic compound to
dampen resonance, and thus helps to minimize modulation noise caused by the
transport mechanism. As a result of these precautions, the K61 can maintain
smooth tape travel under a wide variety of temperature and mechanical load
conditions. The audible pfoof of the system’s excellence is clear, unwavering sound,
and a measured wow and flutter of only 0,04% (WRMS)
Auto-Space/Record
Mute
To provide absolute
silence between recorded selections, teh TC-K61 incorporates a unique Auto-
Space/Record Mute control. The control can be used to automatically attain a
timed, four-second space unwanted program material, such as FM commercials,
with four seconds of silence, or insert longer or shorter gaps, as desired.
Auto Play and Memory
Cue
Another convenience
of the K61’s transport is Auto Play. Auto Play allows you to preset teh deck to
transfer from rewind into play at the beginning of the tape, by simply touching
the rewind and play buttons simultaneously. With the memory feature selected,
the K61 can be put into rewind and it will stop automatically when the tape
counter reads ‘999’. Or with Memory Cue, you can touch the rewind and play
buttons simultaneously to have the deck rewind to ‘999’ and transfer into the
play mode automatically.
Timer Operation
With an external
timer, the K61 can be set to record or play back automatically, at a
predeterminated time. You can have the K61 record FM broadcasts in your
absence, or even wake to music from your high fidelity system. Unlike other
timer provisions, the number of recording or playback operations in the
unattended period is limited only by the capacity of the timer.
LED Meters with Two
Types of Peak Hold
Like the TC-K44, the
K61 incorporates Sony’s sixteen-segment LED Peak Program Meters, whose
parallel-bar arrangement shows channel balance at a glance. In the K61 however,
the meters’ range is calibrated from -40 dB to +8 dB, and there are two methods
of holding the highest-peak indication. In the automatic mode, the peak-hold
re-sets after 2,5 seconds, or when a higher peak is established. Or, if you
wish, you can set the meters for manual hold, at the touch of a button.
Specifications
TC-K61
Number of Heads: Two
Head Type
(Rec/Play): S&F
Erase Head Type:
4-Gap Ferrite
Bias Adjustment:
2-Position Switch for Type I
Drive Type: Belt
Motor Type: Capstan
- BSL; Spooling - High-Torque
Meter Type: Peak
LEDs 16 x 2 parallel
Fast-Forward/Rewind
Time (C-60): 80 sec.
Wow and Flutter:
0,04% (WRMS); 0,12% (DIN 45507)
Frequency Response
(-3 to +3 dB, Re: -20 dB):
Metallic Tape : 30 -
17,000 Hz
FeCr Tape : 30 -
17,000 Hz
EHF Tape : 30 -
16,000 Hz
SHF Tape : 30 -
14,000 Hz
Frequency Response
at Re 0 dB:
Metallic Tape : 30 -
13,000 Hz
Signal-to-Noise
Ratio (Dolby NR Off, Re: 3% THD, Peak, IHF-A weighted):
Metallic Tape : 59
dB
FeCr Tape : 59 dB
EHF Tape : 57 dB
SHF Tape : 52 dB
Improvement with
Dolby NR On : Up to 5 dB at 1 kHz, 10 dB at 5 kHz or Above
Total Harmonic
Distortion (1 kHz, Re: 0 dB Record Level):
Metallic Tape : 1,0%
FeCr Tape : 1,0%
Crosstalk (1 kHz,
tracks): 60 dB
Separation (1 kHz,
channels): 35 dB
Erasure (400 Hz,
incl. Mettallic Tape): 60 dB
Bias Frequency: 105
kHz
Meter Range: -40 ,
+8 dB
Line Input
Sensitivity/Impedance: 77,5 mV/50 k Ohms
Mic Input
Sensitivity/Impedance: 0,25 mV/Low
Line Output:
Level ‘Fixed’: 435
mV
Level ‘Variable’:
27,5 - 435 mV
Line Output: Load
Impedance, Nominal: 50 k Ohms
Load Impedance,
Minimum: 10 k Ohms
Headphone Output
Level: 4,9 - 77,5 mV
Nominal Headphone
Impedance : 8 Ohms
Power Requirements:
AC 120 V, 60 Hz
Power Consumption:
26 W max
Dimensions (W x H x
D): 430 x 130 x 290 mm (17" x 5-1/8" x 11-3/8")
Weight: 5,6 kg (12
lbs 5 oz)
Full-Function Remote
Control: RM-50 (optional