McIntosh MI-350 Amplifier - Front Panel
(Compare with the pics below)
The McIntosh MI-350 and MC-3500
HIGH POWER HIGH-FIDELITY
TUBE AUDIO AMPLIFIERS
The mighty MC3500, reportedly designed by Mila Nestorvic (Nilo Nestorovic??) in about 1968, or its industrial version the MI-350, is unsurpassable - in my humble opinion, the greatest commercial tube amp ever made.
This amp was produced by McIntosh between 1968 and 1971.
SPECIFICATIONS: MC-3500
ELECTRICAL:
350W RMS continuous. 500W RMS Maximum.
Frequency Response: 20-20kHz (+0 -0.5dB).
Total Harmonic Distortion: 0.15%.
Intermodulation Distortion: Unmeasureable - ie behold measuring instrument
threshold
Hum and Noise Levels: -95dB.
Output - Rated Load Impedances: 1, 4, 8, 16, 50 and 64 ohms.
Note: Rated Power Output for 1 ohm load is 300W and 4 Ohm load is 320W
Output Load Circuits: Can be isolated from ground - ie "balanced output".
Internal impedance: less than 5% of Rated Load Impedance.
Input impedance: 200k.
Input sensitivity 1.1V RMS
FRONT PANEL:
Anodized gold and black panel.
Input connectors: RCA and BNC (front and rear).
Gain control.
Meter Range switch: off, volts, dB, dB-10 or V1-V8.
Power circuit breaker: on or off.
Output range switch: 1 , 4, 8, 16, 50, and 64 ohms with corresponding
voltages 17.3, 35.8, 53.0, 75.0, 132 and 150V.
Dual banana output connectors.
Meter: Monitors output voltage, dB or cathode current for each output
tube.
Heavy duty drawer-pull style handles.
BACK PANEL:
Line voltage switch: 117 or 125V.
Output barrier strip.
Input terminals.
Sub sonic filter switch: In or out.
Cooling fan.
TUBES:
8-6LQ6/6JE6B output,
2-12AX7/ECC83,
2-6DJ8/ECC88,
6CG7/6FQ7
6BL7GTA.
Solid state full-wave bridge rectifier.
DIMENSIONS: 19" Wide rack mounting x 10 1/2" High x 17" Deep behind front panel.
WEIGHT: 125 lbs
POWER CONSUMPTION:
400W at zero signal
900W at maximum signal
MANUFACTURE:
Sold from 1968-1971.
1971 retail price USD$1099.00
SPECIFICATIONS - MI-350 :
Generally as for the MC-3500 but with variants not yet identified to me.
The MI-350 has a variable output impedance selector switch knob on the front panel that enables output loads of 1 - 4 - 8 - 16 - 50 - 64 ohms. (Same as for MC-3500)
As far as I can determine to date, there is negligible difference between the two models.
McIntosh MI-350 Amplifier - Front Panel
(Compare with the pics below)
McIntosh MC-3500 Amplifier - Front Panel
McIntosh MC-3500 Amplifier - Internal View with Top Cover removed
Note the chassis layout re the driver stages - the driver tubes are
shielded by the electrolytic filter capacitors
The output transformer is on the left-hand side presumably to provide
right/left weight balance.
Review: Courtesy of "Stereo Review" Magazine, November 1969 Issue
The advice regarding installing a fuse in the loudspeaker circuit is
interesting. If the fuse blew at full output, the owner could expect to
face a truly horrendous repair bill. These days, installation of a core-balance
circuit breaker into the output circuit and controlling a contactor in
the mains supply might be a smarter move.
IMPORTANT COPYRIGHT NOTICE:
Copyright and intellectual property in these audio amplifier designs and circuits remains with their original owner.
Their inclusion in this page as reference materiel is not a license
to reproduce or use them for any purpose contrary
to the terms of any original copyright notice or license.
These reproductions are presented for historical information and education purposes only and are not intended for construction.
No warranty is given of any kind as to fitness for purpose or performance or rating.
Their source is not acknowledged here because I am unable to determine
their origin.
This page was last modified 25 November 2007
This page is located at http://www.webace.com.au/~electron/tubes/MC-3500.html
