ONKYO Integra T-408

Commentary

This FM stereo tuner is equipped with a quartz lock and has pursued the performance of audio equipment by adhering to the concept of TQ = total quality.

It is equipped with a quartz lock system that applies crystal oscillation and realizes excellent tuning accuracy of 0.005% or less of local frequency deviation. Moreover, it is locked to the accurate tuning point instantaneously, enabling excellent tuning.

The front end section consists of a basic configuration of a 5-row varicon exclusively for FM using 2 MOS FET and linear frequency type, and a local generation circuit blocked by Tetoron epoxy board. Furthermore, the input stage is double-tuned, which drastically reduces reception interference (intermodulation interference) caused by two adjacent high-level stations.
In addition, for the first stage (wide) of the IF stage, a MOS FET with a low noise figure and a wide dynamic range was adopted for the first time in place of the conventional bipolar transistor and IC. Furthermore, an AGC is applied to the second gate to ensure linear response at strong input.

The IF stage employs 2-stage bandwidth switching to respond to various radio wave conditions.
In the wide mode, a new 4-element linear-phase filter is adopted in which the center of the flat band is suppressed at 10.7 MHz by the group delay direct-viewing device. By selecting and managing severe characteristics, it is possible to add a phase equalization filter with accurate inverse characteristics that compensates for even slight phase undulations.
In the narrow mode, a 6-element linear-phase filter is added to the front stage of the wide-mode filter to obtain high selectivity.

In the MPX section, a pilot canceler is built into the MPX / PLL IC, and by extending the cutoff of the low-pass filter to 23 khz, the frequency characteristic is expanded to the high band of 18 khz.
Moreover, sufficient NFB is applied to the amplifier inside the IC to reduce the generation of harmonic distortion.

When the 19 kHz pilot signal required for left / right separation is modulated by the audio signal in the MPX section, a beat occurs in the high-frequency range and distortion increases in the mid-frequency range. To prevent this, we have developed our own beat canceler, which extracts a pure pilot signal by cutting all signals except 19 kHz.

In addition to the IF part, wide-band ratio detector and low-distortion MPX part, the ± 2 power supply audio amplifier with a large dynamic margin is used to clear overmodulation with a low distortion factor even at 200% modulation.

Equipped with 50% modulation 440 Hz continuous sound air check calibrator, it is useful for low distortion rate recording with wide dynamic range by setting appropriate recording level.

Equipped with a linear type signal meter.
The signal to the signal meter is detected by three differential type limiters, an IC that does not saturate even with strong input is used, and by applying AGC to the second gate of the IF first stage MOS FET, linear response characteristics up to a strong input level of 80 dB is realized.

Equipped with a multipath output terminal that can detect multipath linearly up to a strong 80 dB input.
Also, by connecting an amplifier to the multi-path V terminal, only the distortion component can be checked by ear.

Model Rating

Type	FM stereo tuner
Receiving frequency	76 MHz to 90 MHz
Practical sensitivity	1.8 μ V (IHF, 300 Ω) 10.3 dBf (new IHF)
S/N50dB sensitivity (IHF)	3.0 μ V 14.8dBf
Image interference ratio	120dB(83MHz)
IF interference ratio	110dB(83MHz)
Signal-to-noise ratio	mono:80dB stereo:75dB
Spurious interference ratio	110dB
2-signal selectivity (± 400 kHz detuning)	50dB(wide) 85dB(narrow)
AM suppression ratio	60dB(wide) 57dB(narrow)
Capture ratio	1.0dB(wide) 2.0dB(narrow)
Distortion factor	Mono, 400 Hz : 0.05%(wide) 0.1%(narrow) Mono, 50 Hz to 10 kHz : 0.1%(wide) 0.3%(narrow) Stereo, 400 Hz : 0.06%(wide) 0.2%(narrow) Stereo, 50 Hz to 10 kHz : 0.15%(wide) 0.4%(narrow)
Frequency characteristic	20 Hz ~ 18000 Hz + 0.2 -0.8 dB
Antenna impedance	75 Ω, 300 Ω
Stereo separation	1kHz: 50dB(wide) 40dB(narrow) 100 Hz to 10 kHz : 40dB(wide) 35dB(narrow)
Carrier leak	-55dB
Output voltage (400 Hz, 100% modulation)	0 ~ 750 mv
Output impedance	2.5k Ω (Maximum Variable Output)
Lock Collection Factor	0.03 or less
Lock offset error	Within ± 3 khz
Semiconductor used	Transistor : 44 pcs FET : 3 IC : 6 Diode : 23 Pieces
Pwer	100 VAC, 50/60Hz
Power consumption	17W (Electrical Appliance and Material Control Law Standard)
External dimensions	Width 438x Height 150x Depth 390 mm
Weight	7.2kg