audio research
M-60

Description
Tube mono power amplifier. Remake of Dynaco Mark III reusing only the transformers. Generally marked 'Electronic Industries'.

The M-60A and M-60B were offered at the same time, where the M-60A was the same as M-60B except with additional provision for regulated 75 Volt 20 ma. supply for FET preamplifier or other application.

Introduced
1968

Discontinued
?

Revisions
M-60A/M-60B
M-60B-2 - Serial numbers are usually around 074220.
M-60B-2R - Serial numbers are usually around 175220. This model is unusual in that it has 2 extra holes in the chassis for some extra tubes that were not incorporated in the final production of this amp. This amp also has a standard AC outlet on the top of the chassis which the other versions of the M-60 amplifier lacked.
M-60C
M-60D - ARC and Fulton musical industries (FMI) had an agreement that FMI could modify the M-60 and sell it with the FMI logo as the M-60D amplifier.

Options
3/16" gray anodized aluminum rack panel (19" W x 10 1/2" H) with cutouts for Rotron fans, together with 1/8" anodized aluminum mounting frame kit for mounting 1 or 2 M-60A or M-60B ($100)

MSRP (US new retail)
$219.50 (M-60A)
$199.50 (M-60B)

Specifications

M-60A/M-60B:

Power output 50 Watts RMS 20Hz/20kHz
Power bandwidth  
Frequency response ± 1 dB 20Hz/20kHz
Input sensitivity 1.15V RMS for 50 W RMS output
Input impedance 500K ohms
Output taps 4-8-16 ohms
Output regulation  
Overall negative feedback  
Damping factor  
Distortion Less than 1% 30Hz/20kHz @ 50 Watts
Slew rate  
Rise time Approximately 20 µs.
Hum & noise 90dB below rated output
Power supply energy storage  
Power requirements 117V 50/60 Hz, approx. 150 Watts at idle, approx. 200 Watts at rated power
Tube complement (1) 12AX7, (2) 6FQ7, (2) 0A2, (2) 6550, (1) 5AR4
Other Load regulation: Approximately 1-172 dB/1kHz
Dimensions 9" W x 10" D x 7" H
Weight 21.5 lbs. Net; 26 lbs. Shipping

Reviews

Pictures

M-60A/M-60B:

M-60B-2:

M-60B-2R:

M-60C:

M-60D: