Dynaco Mark VI Vintage Monoblock Tube Amplifier Pair, 120W

$2,499

This listing is for a working set of Mark VI Monoblocks in working condition.

Features rare XLR inputs for an amplifier this age. Cool bias meter on the front with rack handles.

This pair of amplifiers is labeled "Dynaco Wired", however they have underwent a significant modification at some point in the past.

The majority of the electrolytic capacitors were replaced, film bypass capacitors were added to the various power supply rails, and slow start relay circuits were added to delay the B+ voltages.

Other modifications may have been performed that we are unaware of that sharp Dynaco aficionados may recognize. 

Both amplifiers were tested to their rated power of 120W. Both meter lamps and meters are working properly.

Tubes include RCA 7199, and a mix Sylvania and Philips USA 8417.

Please see our pictures for overall condition.

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - XLR Interconnects

Kimber Kable - Speaker Cables

More from Dynaco:

The Mark VI is a vacuum tube high power basic power amplifier designed for the professional sound installer.

Vacuum tubes are most often favored in their ability to withstand enormous physical and electrical abuse - conditions frequently encountered in discotheques, public address and musical instrument applications.

Its rugged construction and utilization of superior components, including the patented Dynaco Super Fidelity transformers, permit continuous duty at full power, while maintaining safe operating margins.

Protective isolation of the load from the driving circuits, and uniform power output into a variety of load impedances are inherent in all designs which use an impedance matching transformer.

The Mark VI employs a basic circuit arrangement which all Dynaco vacuum tube amplifiers have used since the inception of the Mark II amplifier in 1955.

Refinements of the operating parameters have been incorporated for circuit balance, stability, and for drive capability.

The components used have been selected to protect against failure, and all parts are operated conservatively to assure superior performance and proper operation for many years.

Dynaco Mark VI Professional Power Amplifier - Instructions For Assembly Operation

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 modern and professional tube 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.

Specifications:
Power output:
120 watts into 8 Ω (mono)

Frequency response:
10 Hz to 40 kHz

Total harmonic distortion:
1%

Damping factor:
14

Input sensitivity:
1.6 V

Signal to noise ratio:
95 dB

Speaker load impedance:
4 Ω to 16 Ω

Valve complement:
4 x 8417, 1 x 7199

Dimensions - Each:
19 x 10.5 x 8.75 inches

Weight - Each:
55lbs 

Item

Included

Original Box

No

Manual

Yes

Remote

Not Applicable

Cables

Yes - Power

Physical Condition

6

Working Condition

10

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