Kenwood Model 700T

Kenwood Supreme 700T

December
1 9 7 4 december 1974
1 9 7 9 1979

Part of the original Supreme trio, Kenwood's first set of separates after the Supreme 1 (1967) and the subsequent departure of some engineers to form Kensonic Laboratories, aka Accuphase.

Digital FM tuning wasn't new in 1974, at all.
Heathkit, Harrisson, Fisher or Toshiba had done the basics since the late 1960s but the technique still was very expensive to implement in mid-priced components and sometimes gave way to sci-fi objects with great looks but questionable reliability and ergonomics.

So the Model 700T is a digital tuner... but analogue... but digital.

The reason for this wasn't entirely technical but the refusal to turn a luxurious audio component into a "complex multiple button keyboard arrangement which ignores those human engineering concepts which are so important to the user".
How thoughtful ! Seeing the Sony ST-5555 (1972/73) probably made an impression on the Kenwood engineers :)

Digital tuning of the analogue scale and 5-gang varicap is performed with a 2MHz crystal oscillator and a second, variable, tuned oscillator. The signal of the former is divided by 80 (to get a 25Khz reference ; multiply x4 and you get the width of an FM channel), transformed into digital pulses, compared to the varable oscillator, DC amplified and output to the local oscillator - et voilà !

Also in were two-step muting and a LED-controlled switching of the latter, "exceptional" IF system, a new Pulse Noise Blanking Circuit and Kenwood's traditional DSD (Double-Switching Demodulator) plus a Phase-Locked Loop MPX section - read the TECH1 section for the details !


The Supremes weren't advertised much, saw limited distribution and were very expensive, too ; they seemingly sold best in the US and Germany.
Although "Supreme" was extruded on the faceplates of the first japanese samples, the tag wasn't carried over to the production items and absolutely not outside Japan, even as a marketing name.
The same goes for the magnificent wood enclosures which remained in Japan where only symbolical sales were achieved.

This started Kenwood's strange relationship with its own high-end components, surprising design moves, rapid lineup successions changes and distribution/sales politics.

As a result, bar the L-07C / L-07M series and the L-01A, the Supreme 700 components are very rare.


See the large two-page schematiic of the Model 700C here and the (temporary) fmtunerinfo review of the 700T.

Kenwood Model 700T, image 1 Kenwood Model 700T, image 2 Kenwood Model 700T, image 3
Kenwood Model 700T specifications
Title Value
FM section FM section
Usable sensitivity : 2,0µV
Quieting slope : 4,0µV, 50dB s/n
Frequency response : 20Hz...15Khz (± 10dB)
50Hz...10Khz (± 0,5dB)
THD : 0,2% (mono, 1Khz, 100% mod.)
0,3% (stereo, 400Hz, 100% mod.)
S/N ratio : 70dB (1mV input)
Image rejection : 100dB
Selectivity : 100dB
IF rejection : 110dB
Spurious signal rejection : 110dB
AM suppression : 65dB
Capture ratio : 0,8dB
Stereo separation : 40dB at 100Hz
45dB at 1Khz
40dB at 10Khz
Sub-carrier suppression : 65dB
SCA rejection : 65dB
Antenna impedance : 300 Ohm balanced
75 Ohm unbalanced
Output : 1,5V / 100 Ohm (400Hz, 100% mod.)
AM section AM section
Usable sensitivity : 13µV
S/N ratio : 50dB (1mV input, 30% mod.)
Image rejection : 70dB (1Khz)
Selectivity : 40dB (IHF)
IF rejection : 70dB (1Khz)
THD : 0,5%
Antenna : Built-in ferrite antenna +
external antenna terminals
Output : 0,15V / 100 Ohm (400Hz, 30% mod.)
General General
PC: 20W
Dimensions : 44 x 14 x 30cm
Weight : 13,4kg.
Misc : 4-CH det. output
Tape-rec output
FM Multipath ouputs
Phones level pot (back plate)
Kenwood Model 700T : 0 topic
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page online since : april 2005
page updated : january 2011
page type : LGT / KNB
page weight : 236.64 Kb / 0 b

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