Onkyo TX-4500 - Circuit Description; Tuning Knob; Quartz Locked Circuit; Tuning Meter Circuit

SPECIFICATIONS
MODEL TX-2500 SERVO LOCKED STEREO RECEIVER
Amplifier section
Power Output
Total Harmonic
Distortion
IM Distortion
Damping Factor
Frequency Response
Tilt (sag)
Sensitivity and
Impedance
27 watts per channel,
min.- RMS, at 8 ohms,
both channels driven,
from 40 Hz to 20 kHz,
with no more than 0.5%
total harmonic distortion.
34 watts per channel, min.
RMS, at 4 ohms, both
channels driven, from
40 Hz to 20 kHz, with no
more than 0.5% total
harmonic distortion.
(30 watts per channel, min. RMS,
at 8-ohms both channels driven,
1 kHz, 0.5% THD.)
(40 watts per channel, min. RMS,
at 4 ohms both channels driven,
1 kHz, 0.5% THD.)
0.5% at rated power
0.2% at 1 watt output
0.5% at rated power
0.3% at 1 watt output
40 (8 ohms | kHz 10 watts)
20 — 30,000 Hz (+1 dB)
2 — 60,000 Hz (£1 dB at power
amplifier )
better than 5% at 50 Hz.
PHONO: 2.5 mV 50 kohms
TAPE PLAY: 150 mV 50 kohms
TAPE REC: 150 mV 50 kohms
DOLBY OUT: 150 mV 50 kohms
DOLBY IN: 580 mV 50 kohms
Phono Overload
Bass Control
Treble Control
Signal-to-Noise Ratio
Filter
Tuner section
Tuning Range
Usable Sensitivity
50 dB Quieting
Sensitivity
Intermediate
Frequency
Capture Ratio
Image Rejection
IF Rejection
Signal-to-Noise Ratio
Alternate Channel] att.
AM Suppression
Harmonic Distortion
Frequency Response
Stereo Separation
Muting Level
Stereo Lamp Level
Locking Level
Tuning Meter
150 mV RMS 1 kHz 0.5% THD
+10 dB at 100 Hz
+10 dB at 10 kHz:
PHONO: 65 dB (IHF C NETWORK)
TAPE: 80 dB (IHF C NETWORK)
6 kHz
FM: 88 — 108 MHz
AM: 530 — 1605 kHz
FM mono: 2uV (11.2 dBf)
FM stereo: Suv (19.2 dBf)
AM: 29uV
FM mono: 4uvV (17.2 dBf)
FM stereo: 40uV (37.2 dBf)
FM: 10.7 MHz
AM: 455 kHz
FM: 2 dB
FM: 45 dB AM: 40 dB
FM: 80 dB AM: 30 dB
EM mono: 65 dB
FM stereo: 60 dB
AM: 40 dB
FM: 60 dB
FM: 50 dB
FM mono: 0.2% AM: 0.8%
FM stereo: 0.4%
FM: 30 — 15,000Hz +0.5, -2 dB
FM: 37 dB at 1 kHz
30 dB at 100 — 10,000 Hz
FM: 4yuV (17.2 dBf)
FM: 4uV (17.2 dBf)
FM: 4uV. (17.2 dBf)
Signal Strength & Center Tuning
Specifications and features are subject to change without notice.
CIRCUIT DESCRIPTION
1. Tuning Knob
Touch of the tuning knob causes the ham to be initiated,
which, in turn, is amplified at Q 126, followed by rectifica-
tion at D 119, and 120, while the transistor of Q 135
allows passage thereby causing the signal for the local Si er
oscillation frequency regulation to drop to the earth, thus i
leading to a perfect tuning.
fig—1