audio research
D-250

Description
Tube stereo power amplifier. Unit can be bridged to make a 500 watt mono-block amp.

Introduced
1983

Discontinued
1991 ?

Revisions
D-250 MKII (1984)
D-250 MKII Servo

Options
-

MSRP (US new retail)
$4,995
$5,500 (D-250 MKII)
$6,500 (D-250 MKII Servo)

Specifications

Power output 240 watts per channel minimum continous power (both channels operating) at 16 ohms from 20Hz to 20kHz with less than 1% total harmonic distortion (typically below .005% at one watt output)
  D-250 MKII Servo: 250 watts per channel minimum continuous into 16, 8, 4 ohms from 20Hz to 20kHz with less than 1% THD at rated output and below .005% at 1 watt.
Power bandwidth  
Frequency response  
Input sensitivity D-250 MKII Servo: .8V RMS for rated output.
Input impedance 80 kOhms
Output taps  
Output regulation  
Overall negative feedback  
Damping factor  
Distortion  
Slew rate  
Rise time  
Hum & noise  
Power supply energy storage 550 joules
Power requirements D-250 MKII Servo: 105-125VAC, 2000 watts (20 amps), 900 watts at "idle".
Tube complement D-250: (6) 6922, (4) 7119/7044, (8 matched pairs) 6550, (4) 6550, (2) 12AT7
  D-250 MKII/D-250 MKII Servo: (4) 6922, (4) 7119/7044, (2) 6FQ7, (8 matched pairs) 6550, (4) 6550, (2) 12AT7
Other  
Dimensions 19" W (rack panel) x 10.5" H x 20.75" D (does not include rack handles, front or back)
Weight 120 lbs. Net, 155 lbs. Shipping

Reviews

Number 32 (D-250: Full Review), Number 34 (D-250: Editor's Choice), Issue 36 (D-250 MKII: Special Report), Issue 37 (D-250 MKII: Further Thoughts), Issue 45 (D-250 MKII Servo: Full Review), Issue 50 (D-250 MKII Servo: Capsule)
Vol. 7 No. 8 (D-250 MKII), Vol. 9 No. 5 (D-250 MKII Servo)

Pictures

D-250:

D-250 MKII:

D-250 MKII Servo: