TRIO KA-5500

Commentary

This is a pre-main amplifier designed to improve the characteristics of the equalizer stage by adopting the ICL method or two stage direct connection two power supply configuration.

The equalizer stage employs the first stage FET differential amplification ICL the equalizer stage to improve phase characteristics and transient characteristics.
The circuit configuration is 2-stage direct connection ± 2 power supply configuration.

The power amplifier section employs a first stage differential-amplification all-stage direct-coupled + pure complimentary service OCL circuit. The load circuit for class A amplification is made constant current to improve the stability.

The power supply section uses a large power transformer with good regulation and two 10,000 μ F electrolytic capacitors.

The protection circuit is equipped with double protection circuit by ASO detection type limiter and relay.

The equalizer amplifier section uses a ± 2 power supply system using a low-noise operational amplifier.
It is a low distortion rate tone control in which the CR element is included in the NFB circuit. In the tone defeat position, the CR element of the NFB circuit is disengaged and it becomes a buffer amplifier excellent in DC stability and phase characteristics.

First stage FET differential-amplified ICL equalizer stage, select NFB type tone control, all stages directly connected pure complimentary service OCL power amplifier, all stages use ± 2 power supply system to stabilize the circuit.

Equipped with left and right independent power meters that can read output directly.
W direct reading type can read from 0.01W to 60W, and the meter range can be switched between 60W and 3W.

Equipped with a subsonic filter and -20dB attenuator.

We use a 41-click detent volume for the volume.

There was a Brazilian rose finish wood case sold separately.

Model Rating

Type	Integrated amplifier
Power Amplifier Unit
Rated Output (Both Channel Operation)	20 Hz to 20 kHz : 55W + 55W (8 Ω) 1 kHz : 60W + 60W (8 Ω)
Total harmonic distortion factor	0.1% (8 Ω at rated output) 0.06% (at 1W output, 20 Hz to 20 kHz, 8 Ω)
Cross modulation distortion factor	0.1% (8 Ω at rated output)
Output Bandwidth Characteristics (IHF)	5 Hz to 40 kHz
Signal-to-noise ratio (using IHF A curve)	100dB
Damping factor	30
Optimum load impedance	4 Ω ~ 16 Ω
Preamplifier Section
Input Sensitivity / Impedance	Phono : 2.5mV/50k Ω Tuner, aux, tape play : 150mV/50k Ω
Maximum Allowable Input (1 kHz, 0.1%)	phono:210mVrms
Output level	tape rec(pin):150mV
Signal-to-noise ratio	Phono : 76 dB (5 mV input) Tuner, aux, tape play : 90 dB
Frequency characteristic	Phono : RIAA deviation ± 0.3 dB Tuner, aux, and tape play : 20 hz to 40 khz + 0 to 0.5 db
Tone control	Bass : + / - 10 dB (100 Hz) Treble : ± 10 dB (10 kHz)
Subsonic filter	18 Hz, 12dB/oct.
<General>
Power outlet	Power switch interlock : 2 systems Power switch not linked : 1 system
Power supply voltage	100 VAC, 50Hz/60Hz
Rated power consumption (Electrical Appliance and Material Control Law)	145W
External dimensions	Width 380x Height 140x Depth 255 mm
Weight	10.5kg
Sold Separately	Wood Case SRA-3000 (¥ 4,500)