Audio Database


Lo-D HA-610
85,000yen(1975 release)

The Integrated Amplifier which concentrated the technological result to the output with a Low-noise-izing and allowance.

The transistor for Hi-Fi and constant current drive grounded-emitter inverted Darlington pure complimentary OCL circuitry which were selected carefully are used for a power amplifier part.

The three-step stream composition of a difference input-FET-bipolar transistor is adopted as an equalizer part, and a 280mV dynamic margin has been obtained by driving with ±2 power source.
Moreover, RIAA deflection is suppressed to ±0.3dB by using a high-precision element and sufficient feedback.

The flat amplifier part had adopted the two-step hardwired-connection type by the combination of FET-PNP, applied NFB to alternating-current / direct-current concurrent, and has realized low distortion and quantity stability. Moreover, since the low-impedance drive of the tone control circuit is carried out, the circuitry without the surge of the frequency characteristic has been realized.
Since the defeet organization is carried, it is also possible to remove a tone control circuit.

22 contact switchpoint type Attenuator is adopted as a volume.
Moreover, since high FET of an input impedance is used for the first rank of control amplifier and there is little transition of NF (noise figure) by variation of a source impedance, there is no failure of the SN ratio by a volume location.

Since three steps of gain selectors are carried and an additive expression can also be used, the thing which will be made into a broad range from -5dB to -35dB and to do is possible. Moreover, it is also possible to perform an exact coordination by using it combining a switchpoint type Attenuator.
This gain selector can be used also as an audio muting.

Loudspeaker B level adjustment is carried.
Moreover, a Phono2 level fine tune is possible.

The wood case was sold as an option option.

Rating of a mode
Form Integrated Amplifier
<Power amplifier part>
Circuit system 2 steps of differentials whole page hardwired-connection grounded-emitter inverted Darlington
Pure complimentary OCL
Effective output
20Hz - 20kHz, both ch(es) drive : 70W+70W (4ohms)
60W+60W (8ohms)
1kHz, both ch(es) drive : 90W+90W (4ohms)
70W+70W (8ohms)
1kHz, one-side-channel drive : 100W/100W (4ohms)
75W/75W (8ohms)
Dynamic power (IHF) 180W (8ohms)
THD 0.3% (at the time of an effective output)
0.006% (at the time of 1 / 2 effective output 1kHz)
Cross modulation distortion (70Hz:7kHz=4:1) 0.05% (at the time of an effective output)
0.05% (at the time of 1W output)
Output bandwidth (IHF) 7Hz - 50kHz
Frequency characteristic 7Hz-70kHz+0 -1 dB
Input sensitivity/impedance 0.8V/70kohm
Output-terminal A, B:4ohms - 16ohms
A+B: 8ohm-16ohm
Headphone jack: 4ohms - 16ohms
Dumping factor 60 (1kHz, 8ohms) or more
S/N (IHF, A network, input short-circuit) 100dB or more
<Preamplifier part>
Circuit system Equalizer amplifier: The differential three-step hardwired connection per step, an FET using
Control amplifier: NF form, a first rank FET using
Input sensitivity/impedance Phono1:2mV/50kohm
Phono2:1.6-6mV/50kohm (succession variable)
Tuner, Aux, Tape PB1, 2:100mV/50kohm
Phono maximum permissible input Phono1:280mV (RMS, 1kHz)
2:200-750mV (RMS, 1kHz) of Phono(es)
An Output voltage/impedance
Tape rec1, 2 : 100mV/1kohm
Pre out: 0.8V/4.7kohm (rate)
6V/4.7kohm (maxima)
Frequency characteristic Phono(RIAA deflection): 30Hz-15kHz±0.3dB
Tone control
Bass: ±10dB (50Hz, 100Hz)
Turnover frequency: 150Hz, 300Hz
Treble: ±10dB (10kHz, 20kHz)
Turnover frequency: 3kHz, 6kHz
Filter Low: 20Hz, 12dB / oct
High: 8kHz, 6dB / oct
Loudness control (Volume-30dB) + 13dB (100Hz), +7dB (10kHz)
S/N (IHF, A network, input short-circuit) Phono:75dB
Tuner, Aux, Tape PB: 90dB
Attenuator - 5, -10, -20dB (addition is possible)
The semiconductor used Transistor: 55 pieces
FET: Four pieces
Diode: 29 pieces
Supply voltage AC100V, 50Hz/60Hz
AC outlet Power-switch interlock: One line
Power-switch un-interlocking.: Two lines
Power dissipation
(Electrical Appliance and Material Control Law)
Dimensions Main unit: Width 435x height 144x depth of 388mm
At the time of a wood case using: Width 467x height 179x depth of 400mm
Weight 12.0kg
Option Wood case LA-200 (6,500yen)