Lo-D HMA-8300

Commentary

This is a stereo power amplifier that adopts Dynaharmony (E-class drive) system.

The dynamic harmony method is a circuit method that efficiently realizes a large output of the amplifier through analysis of the level distribution of music. It works as a large output at the peak of the music signal, usually as a small output, and effectively operates as a large output amplifier.
This reduces the weight of the amplifier, expands the safe operation range, reduces the cost, and reduces the distortion factor.

The power section adopts the Dynaharmony system and consists of ± 2 power sources for each of low voltage power source and high voltage power source (total 4 power sources), thereby realizing large output.
Class A driver circuit uses a current mirror circuit for power stage drive.

It is equipped with an external magnetic meter that can directly read the peak output level by the value of power.

It is equipped with a subsonic filter that eliminates harmful vibrations outside the audible band caused by sleds of records.
This filter can be turned on and off as needed.

The transformer used in the power supply section is of a weight class of approximately 9 kg. The power supply Chemicon uses four capacitors with low earth impedance : two 18,000 μ F (63 V) ± 2 power supply dual chemical capacitors and two 10,000 μ F (125 V) capacitors.

As the power increases, the speaker relay adopts a new design for large power supply with rated current (AC15A) and surge current (AC60A), and DC cutoff is also possible.
In addition, the contact structure is a silver contact with a large contact area, and the deterioration of sound quality is reduced by limiting the contact area to 25m Ω or less. In addition, since the arc discharge between contacts, which becomes a problem when cutting off large output due to high power, is blown out by the built-in magnet, deterioration of contact resistance, etc. is reduced even after long-term use.

The carrying handle used in the picture was sold separately as an option.

Model Rating

Type	Stereo power amplifier
Circuit system	2-stage differential-amplification all stages directly connected 4 power supply high-efficiency pure complimentary service OCL (Dynamic harmony system)
Dynamic Power	800W (IHF, 8 ω)
Effective power (both channel drive, THD 0.1%)	200W + 200W (4 Ω, 20 Hz to 20 kHz) 200W + 200W (8 Ω, 20 Hz to 20 kHz) 220W + 220W (8 ω, 1 kHz)
Total harmonic distortion factor (20 Hz to 20 kHz)	0.1% or Less (Effective Output) 0.005% or Less (at 100W Output) 0.03% or less (at 1W output)
Output Bandwidth (IHF)	5 Hz ~ 30 kHz (8 Ω)
Frequency characteristic	5 Hz to 80 kHz + 0 -1dB
Input Sensitivity / Impedance	1V/50k Ω
Load impedance	4 Ω ~ 16 Ω
Damping factor (8 Ω)	50 (20 Hz to 20 kHz) 100(1kHz)
Channel separation	80 dB (1 kHz, 8 Ω)
S/N (IHF, A Network)	110dB
Semiconductor used	Transistor : 40 Diode : 47 Units IC : 2
Power supply voltage	100 VAC, 50Hz/60Hz
Rated power consumption	210W
External dimensions	Width 435x Height 182x Depth 395 mm
Weight	24kg
Sold Separately	Carrying Handle TA-1 (¥ 5,000)