Conrad Johnson MV50 Tube Amplifier - EL34 Tubes - USA Made

$2,299

This is great vintage tube amp from CJ.

This example received a factory film capacitor upgrade to the power supply section.

No tube cover is included but we feel it looks way better without it. 

Please note there's some damage on the output terminal blocks, but they're completely usable and function correctly.

From a TONE review:

The MV 50 was one of Conrad-Johnson’s earliest vacuum-tube power amplifiers, utilizing EL34/6CA7 output tubes, with a modest power output of 45 watts per channel.  As is the way at CJ, this design was steadily improved over the years in the form of the MV-52, MV-55, MV-60 (and the 60SE, which utilized 6550 output tubes for more power) to the recent LP-70 power amplifier, which also uses 6550s, and CJ’s latest CJD Teflon capacitors.

More from Conrad Johnson:

MV50 Vacuum Tube Power Amplifier
The MV50 was, in effect, a more refined version of the earlier MV45. The input voltage amplifier included a cathode follower to provide low impedance drive to the inverter stage, to which it was direct coupled, eliminating one capacitor from the signal path. The remaining coupling capacitors were “cjd” polystyrene. Separate discrete dc voltage regulators supplied dc voltage to the input amplifier and the phase inverter.

Features:
• 4, 8, 16 ohm speaker taps (screw type)
• one pair of inputs
• two plate fuses
• power switch
• rack mount front panel

Specifications:
• 45 watts per channel RMS, at 4, 8, or16 ohms both channels driven from 30Hz to 15kHz with no more than 1% THD or IMD.
• Input Sensitivity: 2.35 Volts RMS to rated power
• Frequency Response: 20Hz to more than 20kHz , +0, -.5dB
• Hum & Noise: 90 dB below 45 watts

Mechanical:
• Dimensions: 19W | 9H | 11.5D inches
• Weight: 39 lbs.

The SkyFi Testing Process for Tube Amplifiers:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and tubes are inspected for signs of stress overheating or cracking.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If it all looks clean we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier the remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will also be tested.

We also test all tubes for output gain and leakage on our calibrated B&K 747 tester against the original manufacturers specifications. If needed, the tubes will be replaced from our vast NOS (New Old Stock) vintage or modern inventory.

Item

Included

Original Box

No

Manual

Online

Remote

Not Applicable

Cables

Yes - Power

Physical Condition

7

Working Condition

10

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