Yamaha K-220 Owner's Manual page 10

With cassette tapes, the most noticeable form of noise is
high-frequency hiss. To reduce this hiss noise, the K-220
has been equipped with a newly developed Dolby C noise
reduction system in addition to its conventional Dolby B
NR. Either type of noise reduction may be selected with
the switch provided,
Dolby B NR has a noise-reduction effect of about 10dB in
the high-frequency range. The corresponding figure with
Dolby C NR is about 20 dB, but this is over the entire
rnage where the human ear is most sensitive to noise
(2 kHz to 8 kHz). Dolby C NR alsa improves the tape's
MOL. {maximum output level).
Dolby C NR has two new circuits: a spectral skewing cir-
cujt and ari anti-saturation network. By improving the
saturation lavel of the tape it is possible to prevent high-
frequency loss and encode/decode error, etc., improve
dynamic range and signal-to-noise ratio, and make it easier
+10
: Frequency response C Tyne
dB
ee B Type
" {—10dB) =~
=EN " (—20d8) w~
Level (dB}
L
©
—60 Dolby off
Noise reduction effect
—80
20 100 500 ik 2K 5K 10K 20K
Frequency (Hz)
to set the recording level. With Dolby C NR, it is possible
to achieve the same noise reduction effect at both high
and low signal levels and to set the recording level at a
point where side effects such as "breathing" are eliminated.
Also, by expanding the operating frequency range to two
octaves more than that of Dolby B NR, overall noise
balance is obtained and the system also becomes effective
against high frequencies from the power supply.
The graph shows the frequency response and the noise-
reduction effect of recording and playback with Dalby B
NR and Dolby C NR. The noise reduction effect of Dolby
C NA is larger — approximately 20 dB.
Dolby noise reduction is a 2-part process that acts both on
recording and playback; be sure that the Dolby NR switch .
is set to the same position on record and play.
* Noise in the source material can not be reduced with
the Dolby NR system,
TV BO pea ee ak eS wae ee. 4-track, 2-channel record-
ing and playback stereo
cassette tape deck
Rec/Play head ........ Hard permalloy
Erase head, ......,..-.. Ferrite
Motors
Capstan g ore. circa le: a d DC servo motor
PRO! tg hoe eee Bh ee Ss a Flat torque DC motor
Wow and Flutter ........ No more than +0.15% W.peak
0.08% W.RMS
Fast winding time ....... Approx. 95 seconds (C-60)
Frequency response
Normal tape (—20dB) .... 40 to 16,000 Hz +3dB
Chrome tape (—20dB) .... 40 to 16,000 Hz +3dB
Metal tape (~20dB) ...... 40 to 16,000 Hz +3dB
Signal to Noise ratio
Dolby off x uteri. oe Gt dy he Vans ' 68 dB
Dolby BON age cw sk et .. 66dB
Dolby Con 3-44 ata scx 740B
Harmonic distortion ...... Less than 1%
Input Sensitivity/Impedance
EINS? ce gti hcg! Be Sots, fe oige N 45 mV/50 k-ohms
Output Level/Load Impedance
LING: soared, Oe, a ard 360 mV/47 k-ohms
Headphones.......... 40mV/8 ohms
Power supply .......... AC120V, 60Hz
Power consumption. ...... 15W
Dimensions (W x Hx D ) . ... 435x112 x 225 mm
(17-1/8" x 4-3/8" x
8-7/8"')
Weight .............. 4.0kg (8 Ibs 13 oz)
Specifications subject to change without notice.