TRIO KA-9900
¥ 200,000 (released in 1978)
Commentary
An integrated amplifier developed by integrating three types of amplifier technologies such as DC amplifier and high-speed amplifier.
TRIO's original straight DC amplifier with multi-stage DC amplifiers is used, and there is no low-frequency cut capacitor between the Tuner (Aux) input and the speaker terminal.
The DC-configuration MC head amplifier uses an all-stage complimentary service push-pull circuit that uses a low-noise transistor in parallel connection at the first stage.
In the first stage of the equalizer amplifier section, a cascode differential amplifier with a high-gain current mirror using an ultra-low-noise FET is adopted. In order not to decrease the gain of the first stage, an emitter-follower is installed in the second stage and the last stage is equipped with a complimentary service push-pull circuit.
Since the SN ratio of the FET used for the input is hardly affected by the signal source impedance, an excellent SN ratio can be obtained even when the MM cartridge is mounted.
This equalizer amplifier also has a DC configuration.
The Phono1 position has an impedance 3-stage switching function.
It uses a four connected volume made of conductive plastic.
Conductive plastic is an extremely smooth resistor with a uniform thickness and a surface smoothness of less than 0.2 μ m. In addition to using this excellent resistor, the S / N ratio is greatly improved when the volume is narrowed down by combining two volumes at the front and back of the flat amplifier into four strands.
The flat amplifier section consists of a constant-current drive current mirror load cascode-connected FET differential amplifier circuit, a current mirror load differential amplifier circuit, and a complimentary service push-pull circuit.
A one chip FET with uniform temperature characteristics is used for the first stage differential amplifier circuit, and a dual transistor is used for the current mirror, cascode, and constant current circuits to suppress temperature drift.
TRIO's original NF-CR type circuit using ultra-low noise IC is adopted for the tone control circuit.
This tone amplifier has a gain of 0 dB and is a linear step type that does not invert the phase.
The high filter uses an ultra-low noise IC, which was developed for equalizer amplifiers as well as tone amplifiers.
The subsonic filter uses a non-polar electrolytic capacitor that is carefully selected for sound quality.
The power amplifier section is a DC amplifier consisting of three differential stages and all stages directly connected ICL and OCL circuits with a cascode-connected FET differential amplifier at the first stage and a third stage differential amplifier connected to a current mirror load.
In the final stage, a newly developed super linear transistor is used in parallel connection to realize high output with low distortion.
The power amplifier is powered by two power sources on the right and left sides using four large electrolytic capacitors of 18,000 μ F and two large transformers. When a large signal enters one channel, it affects the other channel through the power supply and suppresses dynamic crosstalk that interferes with sound image localization.
In addition, the KA-9900 has separate windings and a constant voltage power supply for the pre-section and tone section to reduce interference caused by the power supply.
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Model Rating
| Type | Integrated amplifier | ||
| Overall Characteristics | |||
| Rated output (phono → sp terminal, both channel operation) |
150W + 150W (8 Ω, 20 Hz to 20 kHz) 180W + 180W (4 ω, 1 kHz) 150W + 150W (8 ω, 1 kHz) |
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| Total harmonic distortion factor (8 Ω) |
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| Cross modulation distortion factor | Tuner, Aux, Tape → SP terminal : 0.0045% (at rated output, 8 Ω, 60 hz : 7 khz = 4 : 1) | ||
| Frequency characteristic | Tuner, Aux, Tape → SP jacks (straight DC on) : DC ~ 400 khz -3dB Tuner, Aux, Tape → SP jacks (straight DC off) : 1 Hz to 400 kHz -3dB |
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| Output Bandwidth (IHF) | Tuner, Aux, Tape → SP terminal : 5 Hz to 100 kHz (8 Ω at 0.03% distortion rate) | ||
| Damping factor | 100 (Tuner, Aux, Tape to SP terminal, DC to 20 kHz, 8 Ω) | ||
| Input Sensitivity / Impedance | Phono MM → SP Terminal : 2.5mV/33, 47, 100k Ω Phono MM → SP Terminal : 2.5mV/47k Ω Phono MC → SP Terminal : 0.1mV/100 Ω Tuner, Aux, Tape → SP terminal : 150mV/50k Ω |
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| Signal-to-noise ratio (IHF-A) | Phono → SP Terminal : 90 dB (2.5 mV input) Phono MC → SP Terminal : 70 dB (0.1 mV input) Tuner, Aux, Tape → SP terminal : 105 db |
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| Tone control (Tuner, Aux, Tape → SP connector) |
Bass : ± 7.5 dB (150 Hz, 75 Hz) Treble : ± 7.5 dB (10 kHz, 20 kHz) |
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| Loudness control | + 3 db, + 6 db, + 9 db (Tuner, Aux, Tape → SP terminal) | ||
| Transient response | Rise time : 0.8 μ s (Tuner, Aux, Tape → SP terminal) Slew rate : ± 230 V / μ s (Tuner, Aux, Tape → SP terminal) |
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| Phono maximum allowable input (Rec out, 1 kHz) |
MM : 230 mV (distortion rate 0.01%) MC : 9 mV (Distortion rate 0.01%) |
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| Phono RIAA deviation | 20 Hz to 20 kHz ± 0.2 mV | ||
| Output Level / Impedance | Tapre rec pin : 150mV/180 Ω DIN : 30mV/80k Ω Pre out (max) : 9V/750 Ω |
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| Power Amplifier Section (Power in → SP Terminal) | |||
| Total harmonic distortion factor | 0.005% (Rated Output, 20 Hz to 20 kHz, 8 Ω) | ||
| Signal-to-noise ratio (IHF-A) | 110dB | ||
| Input Sensitivity / Impedance | 1.0V/50k Ω | ||
| Rise time | 0.6 μ s | ||
| Slew rate | ± 230 V / μ s | ||
| <Others> | |||
| Power outlet | Power switch interlock : 2 systems Power switch not linked : 2 systems |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||
| Rated power consumption | 400W (Electrical Appliance and Material Control Law) | ||
| External dimensions | Width 460x Height 161x Depth 463 mm | ||
| Weight | 25.8kg | ||