Audio Database

The

Technics EAA-2009/SU-2009/SU-40A/Technics 40A 65,000yen (March, 1968 release)
69,500yen (around the 1970 time)

Description
 
Stereo power amplifier of a tube.
The model number is changed 3 times with EAA-2009, SU-2009, and SU-40A.

The Mullard form is used for circuitry, the low noise tube 6267 is adopted as the first rank, and low internal resistance and 12AT7 of a high amplification factor are adopted as the driver stage.
Moreover, the thing with a cathode coil is adopted as an output transformer, and high output of a pentode and coexistence of low internal resistance of the triode are aimed at by covering cathode NF of 6dB over an output tube.
Moreover, NF of a main loop is 20dB and the distortion at the time of an Output power is suppressed to 0.1% or less.

The circuitry is adopted as the bridge which combined current feedback and a voltage feedback, and it can carry out variable of the dumping factor continuously from infinity from +0.5 to -3, without changing gain.
This dumping factor variable functionality can choose the two-step of all the bands and a bass region of 500Hz or less by the change of a switchpoint.

The level control of a right-and-left independency, the low-pass cut-off filter (15Hz or less, 6 dB/oct), the speaker phase circuit changing switch, and the speaker impedance circuit changing switch are carried in the interior of the front panel

(from the left)
- Low noise-tube 6267 - high-L-tube 12AT7 - Output transformer
Internal
(from the left)
- AC outlet - Fuse - B speaker - A speaker - input terminal


Rating of a mode
Form Tube main amplifier
Music power 30W+30W (16 ohms, 0.1% or less of a distortion, 1kHz)
28W+28W (8 ohms, 0.1% or less of a distortion, 1kHz)
26W+26W (4 ohms, 0.15% or less of distortion)
Output power 25W/25W (16 ohms 0.1% or less of a distortion, 1kHz)
24W/24W (8 ohms 0.1% or less of distortion)
22W/22W (4 ohms 0.15% or less of distortion)
Frequency characteristic (at the time of 10W output) 4Hz - 50kHz, and +0 -3 dB
S/N ratio (A curve) Input short-circuit: 103dB
Input Open: 92dB
Input sensitivity 170mV (4ohms)
160mV (8ohms)
150mV (16ohms)
Input impedance 100kohm
Dumping factor - 3-infinity-+0.5 (succession variable)
It is a change possible to a perimeter wave number band (10Hz - 20kHz) and 500Hz or less (10-200Hz).
Light filter Low-pass cut-off filter: 15Hz-6dB / oct
The semiconductor used
Thermionic tube : 6267:2 pieces
7:2 12AT
26:4 50HB
Diode : Five pieces
Power source AC100V, 50/60Hz
Power consumption At the time of a non-signal: 85VA
At the time of 25Wx2 output: 145VA
Dimensions Width 360x height 150x depth of 330mm
Weight 14.8kg