Marantz Model 500 595,000yen( at the 1972 time(?))

Stereo power amplifier which how the distortion of a high region at the time of full power is pressed down as a high power machine or how the distortion at the time of mini power is lost pursued, and was developed.

What a Marantz and Motorola, Inc. developed jointly is adopted as a power transistor, and SJ is attached to the model number after M.
Moreover, made-to-order resistors and switchpoint are adopted.

The hardwired-connection preamplifier part of SEPP which circuitry allotted the differential-amplification circuitry first is placed, and the power amplifier part of the usual whole page hardwired-connection pure complimentary OCL continues after that.
NF is doubly hung from the end of a preamplifier part, and the output unit of the power amplifier part.
The perfect push pull was used for the power amplifier part from the entry point to the outlet for the first time in the world. For this reason, even if it used the top's differential circuit, it was separately prepared for the up-and-down completeness, and to the last stage of a pure complimentary, the up-and-down independency was achieved completely, it amplified, and perfect symmetric property and dynamic behavior have been acquired.

Power stages are 8 parallel stone stream compositions 4 stones, and are carrying out 3 stone Darlington (counting 4 stone parallel with one stone) adoption at one side ch. Sufficient idling electric current is sent, AB class operation of this power transistor is carried out, and a notching distortion peculiar to transistor class B amplification is pressed down.

When a certain unusual operation takes place, the thing of 2 stone stream compositions which prevent stopping an electric current in the drive stage and an excessive electric current flowing into a power transistor is used for a protection network.
The limiter circuit of the power change of 500W/300W/100W is using a part of this protection network, and its principle of operation is also the same.
Moreover, in a speaker protection network, if direct current voltage appears in a speaker termination with the amplifier of 3 stone stream compositions, the output of a speaker terminal and power amplifier is intercepted by relay, and this serves also as the muting to it.
Use a relay for the rush-current preventing at the time of the power source ON for those with three piece in all, one is used for it, and remaining two are used for the prevention from a direct current of a muting-cum-speaker termination.

The forced-air-cooling fan is carried in the interior. 

Form	Stereo power amplifier
Output	8ohm(at the time of an Output power both channel, 20Hz - 20kHz): 500W (250W+250W), Typically 600W
THD	0.05% or less (at the time of 20Hz - 20000Hz, both channel, and an Output power)
Cross modulation distortion	0.05% or less (at the time of an Output power both channel, SMPTE)
Frequency characteristic	20Hz-20kHz±0.1dB
Power band Wiz (IHF)	5Hz - 45000Hz (THD 0.1%)
Input sensitivity	2.25V for 250W into 8 ohm load with Gain Controls fully clockwise.
Input impedance	33 kohm with Gain Controls fully clockwise.
Dumping factor	400 or more
Total Noise	better than 106dB below 250W Power (8ohm Load)
<Synthesis>
Voltage Conversion	Special tapped primary allows easy conversion to 110VAC or 220 VAC operation
Control	Independent front panel Gain Controls and Power Level Selector Switch
Dimensions	Width 425x height 171x depth of 435mm
Weight	37.6kg

Posted in: Marantz, Marantz-Amplifier, Marantz-Amplifier-Separate, Marantz-Amplifier-Separate-Stereo