Marantz model 9 (1960 - 1968)

Marantz Model 9 Seventy Watt Amplifier
Sleek, efficient beauty hallmarks the unparalleled performance of this massive single-channel 70 watt amplifier. Here is the instrument that proves just how much difference an amplifier can make in high fidelity reproduction. Exceptional stability and low distortion team with its tremendous reserves of power to produce the finest sound available today. Its precision design and construction is mirrored at every point - from superb transient response to the built-in metered adjustments. If you've a taste for luxury and a desire for the purest of sound reproduction, satisfy it with the Marantz Model 9.

SPECIFICATIONS
Power: 70 watts continuous - 140 watts peak. Switch for 40 watt triode operation.
Response: At full rated power; within 0,1 dB - 20 cps to 20 kc; within 1 dB - 12 cps to 40 kc. At 0,5 watt, within 1 dB - 3 cps to 40 kc
Harmonic Distortion: At full rated power; less than 0,1% at mid-frequencies, less than 0,33% - 20 cps and 20 kc.
I.M. Distortion: less than 0,5% at full rated power.
Hum & Noise: better than 100 dB below 70 watts.
Damping Factor: 17. Damping factor may be changed internally by adding current feedback.
Output Impedances: 4, 8 and 16 ohms, plus 1 ohm tap for center-speaker conection.

Construction: Instrument type, precision construction throughout. Circiut assembled on rigid heavy-duty terminal board with machined, silver plated turret-terminals. Wiring connections neatly cabled. Silicon diode B + and bias supplies, with Zener regulation for first stage. Three Sprague type 17D telephone-grade electrolytic capacitors. Over-sized transformers for very cool operation. Heavy front panel with precision-machined knobs, precision d'Arsonval meter, etc.
Test Section: Complete built-in instrument for self-testing and balancing of output and driver tubes. Adjustments for balance of driving signal. The circuit includes five scrowdriver adjustments, a seven-position test switch, and an accurately calibrated d'Arsonval meter. These simple adjustments eliminate the need for matched output tubes and assure optimum performance despite normal tube aging.
Controls: All controls, adjustments and connections with the exception of the Triode switch, are accessible from the front.
Gain Control: Isolated by cathode-follower / phase-reversal circuit.
Phase Switch: For securing corect phase relation (A +B) of phantom center channel speakers fed by two amplifiers.
Low Filter: Subsonic cut-off filter, less than 0,25 dB @ 20 cps - 20 dB @ 3 cps
Test Switch: For bias (plate current) readings for each tube. Built-in test signal for dynamic balance adjustment. Five bias and balance adjustments, as well as all input and output connections are located under snap-out panel
Tube Complement: 2 x 6DJ8/ECC88; 1 x 6CG8; 4 x 6CA7/EL34; 1 Zener Diode; 5 Silicon rectifiers.
Overall Dimensions: 15⅜" x 8¼" x 10½" (W x H x D); Panel 15⅜" x 7¾" (W x H)
Shipping Weight: 60 lbs