Technics EAA-2009/SU-2009/SU-40A/Technics 40A
¥ 65,000 (released in March 1968)
¥ 69,500 (around 1970)
Commentary
Tube bulb type stereo power amplifier.
The model number has been changed 3 times : EAA-2009, SU-2009 and SU-40A.
The Mulard type is used for the circuit configuration. Low-noise tube 6267 is used for the first stage, and 12AT7 with low internal resistance and Takamasu depth factor is used for the driver stage.
The output transformer is equipped with a cathode winding. By applying a 6 dB cathode NF to the output tube, both the high output of the 5-pole tube and the low internal resistance of the 3-pole tube are achieved.
The NF of the main loop is 20 dB, and the distortion at the rated output is suppressed to 0.1% or less.
A circuit is adopted in the bridge which combines current feedback and voltage feedback, and the damping factor can be continuously varied up to + 0.5 ～∞～-3 without changing the gain.
With this variable damping factor function, you can select two levels by switching the switch : the whole band and the low frequency range of 500 Hz or less.
Inside the front panel, there are independent level controls on the left and right sides, a low-cut filter (15 Hz or less, 6dB/oct), a speaker phase switch and a speaker impedance switch.
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Model Rating
| Type | Tube type main amplifier | ||||
| Music power | 30W + 30W (16 Ω, Distortion Factor 0.1% or Less, 1 kHz) 28W + 28W (8 Ω, distortion rate 0.1% or less, 1 kHz) 26W + 26W (4 Ω, Distortion Factor 0.15% or Less) |
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| Rated output | 25W/25W (16 Ω, Distortion Factor 0.1% or Less, 1 kHz) 24W/24W (8 Ω, Distortion Factor 0.1% or Less) 22W/22W (4 Ω, Distortion Factor 0.15% or Less) |
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| Frequency Response (at 10W output) | 4 Hz to 50 kHz, + 0 -3dB | ||||
| S/N ratio (A-curve) | Input short : 103 dB Input Open : 92 dB |
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| Input sensitivity | 170 mv (4 Ω) 160 mv (8 Ω) 150 mv (16 Ω) |
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| Input impedance | 100k Ω | ||||
| Damping factor | -3 ～∞～+ 0.5 (continuously variable) Switchable between full frequency band (10 Hz ~ 20 kHz) and 500 Hz or less (10 ~ 200 Hz) |
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| Filter | Low-pass cut filter : 15 Hz, -6dB/oct. | ||||
| Semiconductor used |
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| Pwer | 100 VAC, 50/60Hz | ||||
| Power consumption | No signal : 85 VA 25Wx2 output : 145 VA |
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| External dimensions | Width 360x Height 150x Depth 330 mm | ||||
| Weight | 14.8kg |