Lo-D HA-510

Commentary

A pre-main amplifier with low distortion and high output.

The power amplifier section uses carefully selected Hi-Fi pair transistors and is made of emitter-grounded inverted Darlington pure complimentary service.
In addition, by adopting a stable differential amplification constant current drive system in the driver stage, crossover distortion at the time of very small output is suppressed and high sound quality is achieved.

The equalizer stage of the preamp section has a 3-stage configuration consisting of first stage differential input, FET and bipolar transistor. By driving this circuit with ± 2 power supply, a dynamic margin of 280 mv is obtained.
A high S/N ratio has also been achieved by using carefully selected Hitachi LTP transistors.
The flat amplifier section is a 2-stage direct connection type by the combination of FET-PNP, and low distortion and stability are achieved by applying NFB simultaneously with AC and DC.
By driving the tone control circuit with low impedance, ideal tone control without undulation of frequency characteristics is realized.

The volume uses a 22-contact switch type attenuator.
An FET with high input impedance is used in the first stage of the control amplifier, and it is combined with a switch-type attenuator to achieve accurate level attenuation. Moreover, by using an FET, the change of NF due to the variation of signal source impedance is small, and there is no degradation of SN ratio due to volume position.

The level of the speaker jack B can be adjusted up to -15dB.
This makes it possible to adjust the level of the speakers at the time of comparative listening.

The Phono2 terminal is equipped with an input sensitivity selector switch that can be used according to the output of the cartridge.

The protective circuit contains Lordi's proprietary electronic protective circuit.

Built-in features such as tone defeat, low filter, mode switch, loudness and microphone jack.

The wood case was sold separately as an option.

Model Rating

Type	Pre-main amplifier
Power Amplifier Unit
Circuit system	Differential 1-stage all stages connected to ground emitter inverted Darlington Net complimentary service OCL
Effective power	20 Hz to 20 kHz, both channel drive : 50W + 50W (4 Ω) 43W + 43W (8 Ω) 1 kHz, both channel drive : 65W + 65W (4 Ω) 50W + 50W (8 Ω) 1 kHz, single-channel drive : 80W/80W (4 Ω) 56W/56W (8 Ω)
Dynamic Power (IHF)	140W (8 Ω)
Total harmonic distortion factor	0.3% (Effective Output) 0.008% (1 kHz at 1/2 effective output)
Intermodulation distortion factor (70 hz : 7 khz = 4 : 1)	0.05% (at effective output) 0.05% (at 1W output)
Output Bandwidth (IHF)	8 Hz to 45 kHz
Frequency characteristic	10 Hz ~ 30 kHz + 0 -1dB
Input Sensitivity / Impedance	0.7V/70k Ω
Output terminal	A, B : 4 Ω ~ 16 Ω A + B : 8 Ω ~ 16 Ω Headphone terminal : 4 Ω ~ 16 Ω
Damping factor	60 or More (1 kHz, 8 Ω)
S/N	100 dB (IHF, A Network, Input Short)
Preamplifier Section
Circuit system	Equalizer amplifier : 1-stage and 3-stage differential directly connected, with FET Control Amplifier : NF Type, First Stage FET Used
Input Sensitivity / Impedance	Phono1 : 2mV/50k Ω Phono2 : 2 ~ 5mV/50k Ω (Low/High switching) Tuner, Aux, Tape PB1, 2 : 100mV/50k Ω Mic : 2mV/25k Ω
Phono maximum allowable input	Phono1 : 280 mV (RMS, 1 kHz) Phono2 : 280 to 750 mV (RMS, 1 kHz)
Output Level / Impedance	Tape rec1, 2 : 100mV/1k Ω Pre out: 0.7V/4.7k Ω (Rating) 6V/4.7k Ω (maximum)
Frequency characteristic	Phono (RIAA deviation) : 30 Hz to 15 kHz ± 0.3 dB
Tone control	Bass : ± 10 dB (100 Hz) Treble : ± 10 dB (10 kHz)
Filter	Low : 40 Hz, 6dB/oct.
Loudness control	+ 9 dB (100 Hz), + 4 dB (10 kHz) (Volume -30dB)
S/N (IHF, A-network Input short)	Phono:75dB Tuner, Aux, Tape PB : 90 dB
<General>
Semiconductor used	Transistor : 44 pcs FET : 4 pcs Diode : 35 pcs
Power supply voltage	100 VAC, 50Hz/60Hz
AC outlet	Power switch interlock : 1 system Power switch not linked : 1 system
Rated power consumption	105W (Electrical Appliance and Material Control Law)
External dimensions	Body : Width 435x Height 144x Depth 388 mm Wood Case : Width 467x Height 179x Depth 400 mm
Weight	10.8kg
Sold Separately	Wood Case LA-200 (¥ 6,500)