Der Vorverstärker "model 7" macht ja noch keine Musik. Dazu braucht man die Endstufe "model 8B".
Rückwärts gesehen, war die Auswahl an dicken Röhrenendstufen rar. Mit je 2 von den bekannten Röhren - zum Beispiel der berühmten EL34 - konnte man etwa 30 Watt Sinus herausholen. Danach war die Qualität mau - bei 5% Klirrfaktor. Die Amerikaner hatten da noch ein paar Tricks auf Lager und konnten sogar 35 edle Watt anliefern. So auch der Marantz model 8B. Schön sah das Teil nicht aus, es war dafür aber auch preiswert (im Vergleich zum McIntosh 240), jedenfalls in den USA.
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Marantz Dual Thirtyfive Stereo Power Amplifier model 8B
The Model 8B Stereo Amplifier is essentially two 35 watt amplifiers on one compact chassis. It features the highest quality of performance. All connections are made on the rear, making it ideally suited to exposed installation (for example: bookshelves, room dividers, etc.). With its optional grille snapped in place, it presents a smooth, uncluttered appearance with all tubes and wires hidden from view. Simple built-in metered adjustments provide assurance of correct operation despite tube aging.
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POWER OUTPUT
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- POWER OUTPUT, PER CHANNEL:
35 Watts (70 Watts Peak) "Ultra-Linear" operation. Nearly 20 Watts of excellent Triode operation can be had by altering two connections inside chassis.
(es müssten da 2 x 35 Watt Sinus bei 1.000Hz herauskommen.) - OUTPUT CONNECTIONS 4, 8 and 16 ohms.
- INPUT SENSITIVITY FOR 35 WATTS 1.3 volts RMS into 250K.
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RESPONSE
At 35 Watts: Within 0.2db from 20cps to 20kc (equivalent of ±0.1db). Within 1db from 15cps to 40kc into "Grid" input. At 1/2 Watt: ±1db from 3cps to 40kc. Response has been deliberately rolled off approximately 7db at 100kc to control transient response. Subsonic Filter in standard "INPUT" slowly rolls response off below 20cps (Less than 1db at 20cps; - 10db of 3cps; etc.)
DISTORTION
Total Harmonic Distortion at 35 Watts: Less than 0.7% at mid-frequencies. Less than 0.5% from 20cps to 20kc. Intermodulation Distortion at 35 Watts equivalent (70 Watts Peak) Less than 0.5% (60cps/l2kc, 4:1); (I.M. measurement of typical amplifier: 35 W. equiv. 0.5%; 30W. equiv., 0.28%; 20W. equiv., 0.17%; 10W. equiv., 0.11%). Distortion below 35 W is largely of 2nd order and reduces rapidly with signal level.
DAMPING FACTORS
Greater than 20 from 20cps to 20kc. (Instructions given for optional insertion by the customer of two additional resistors to provide damping factors of 2, 1, or 1/2.)
INVERSE FEEDBACK AND STABILITY
20db of overall feedback. Great care has been taken to ensure stability and low distortion under widely varying loads, both resistive and reactive, such as are encountered in loudspeaker systems. Power supply surges are balanced out of signal channels providing excellent recovery from strong transients. Will not oscillate under any condition of open circuit capacitive load.
HUM
Better than 90db below 35 Watts containing proportionately little of high order components.
METERED TESTS AND ADJUSTMENTS
Built-in meter and test switch provide accurate adjustment of each output tube bias. This makes the use of matched tubes unnecessary. Adjustable A.C. Balance (located sub-chassis) preset at factory.
POWER SUPPLY
The use of Silicon rectifiers, three telephone quality electrolytics, and a choke, provide improved regulation, and thorough filtering, together with long life.
POWER REQUIREMENTS
Design center: 117 volts, 60 cycles. Range: 105-125 volts, 50-60 cycles. 170 Watts at zero signal; 250 Watts at maximum signal.
Anmerkung: Es gab da schon eine 50 cycles Exportversion mit 220 bis 240V Trafo.
TUBE COMPLEMENT - 2-6BH6, 2-6CG7, 4-EL34/6CA7.
SIZE : 13 1/2" W x 7 1/4" H x 10 1/2" D - SHIPPING WEIGHT: overall 55 lbs.
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Und wieder der Preis :
$264.00 (less grille) - (Higher in West)
Gold-finish perforated grille - $9.00
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Anmerkung: Der Preis - hier für Vor- und Endverstärker - war aus unserer europäischen Sicht absolut genial-preiswert. Für die Amerikaner waren aber etwas über $500.- bereits recht viel, zumal da noch ein Plattenspieler, ein Tuner und 2 Boxen dazu gehörten.
Dazu muß man aber auch noch wissen, daß zum Beispiel Dual zum Ende 1963 mit dem brandneuen Dual 1009 in den USA zu einem sagenhaften Niedrigpreis einstieg, nämlich für knappe 99.- Dollar. Das war damals in den USA der Hammer. Und er hat einige andere amerikanische "Mitbewerber" umgeworfen.
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