Luxman MB8A Mono Tube Amplifiers with KT88 Tubes - Rare and Collectible

Free Shipping on *ALL* Electronics (Excluding Speakers, Contiguous 48 US States Only)

Super neat industrial looking tube amps from Luxman's Golden Era back in the 1960's.

Fitted with KT88 tubes and ready to rock your high-efficiency speakers.

Also tastefully modernized to accept modern speaker banana connections, and attenuators were added for each channel so you can perfectly match your preamp.

Both are working exactly as they should, fully tested, serviced, and biased.

Include tube cages, power cables, and speaker jumpers.

Specifications (Translated from Japanese):

Model
Tube monaural power amplifier

Input voltage
0.9V

Output Power
70W (20Hz-20kHz)

Output Impedance
4Ω, 6Ω, 8Ω, 10Ω, 16Ω

S/N Ratio
90 dB or more

Frequency Characteristic
12Hz ~ 25kHz -1dB

Negative Feedback
28 dB

Distortion
1% (20Hz)
0.4
% (30Hz to 10kHz) 1% (17kHz, maximum)

Vacuum Tubes:
12AU7x2
6GB8x2
5AR4x2

Power Supply For Preamp/Tuner
For DC310V 50mA
Heater: 6.3V3ACT/12V1A

Power Supply
AC90-110V, 50Hz/60Hz

Power Consumption
About 110W (without signal)
About 200W (at maximum output)

External dimensions
Width = 17.52" (445mm)
Height = 9.69" (246mm)
Depth = 7.80" (198mm)

Weight
36.81 lbs (16.7kg)

The SkyFi Testing Process for Amplifiers (Tube):

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.

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage KEF speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.