McIntosh MC30 Tube Monoblock Amplifiers - Full Blown Restoration

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Likely to be the cleanest and most perfect MC30's on the market, having undergone a price no object restoration.

They look and work better than the day they left the factory many decades ago.

The restoration goal was to make these classics as reliable and as cosmetically clean as possible, without disturbing their special vintage sound quality.

With regards to sound quality, the MC30 is considered to be the most desirable McIntosh model among audiophiles and collectors. It was only produced from 1954 to 1962, and unlike other McIntosh Tube amps there were no later model anniversary or commemorative editions produced.

SkyFi Restoration Notes:
Both MC30's underwent an extensive professional restoration as follows:
• New and professional reproduction chrome chassis.
• Three-Prong power cord - Note no ground connection. This modification forces proper hot/neutral connection at the outlet.
• Multi-section filter can replaced, and new power resistors installed for the B+ Supply.
• Bias Diode replaced with a Silicon unit.
• All signal path capacitors replaced with film and Russion PIO, with the exception of the "bumblebee" capacitor on the preamp input socket.
• Select resistors replaced on the peg board
• New terminal block
• Bottom cover and transformers appear to have been repainted

Both MC30's performed amazingly well on our bench tests. They are perfectly balanced to one another. Clipping at just under 35W each into 8 ohms.

Tube Notes:
Each MC30 is loaded with a carefully hand selected set of vintage driver and rectifier tubes, along with current production Tung-Sol 6L6GC output tubes.

The writing on the tube bottles from left to right channel vary, but they are the same brand/production tube from L/R Channel.

All tubes were tested for in-spec plate current, Gm, and microphonics, on our modern and professional Amplitrex AT-1000 tube tester. Yes the tube test results are available upon request.

V1 - 12AX7 - Telefunken (The Fisher Branded)
V2 - 12AU7 - GE
V3 - 12BH7 - GE
V4 - 12AX7 - RCA

Rectifiers - 5U4GB - GE

Output Tubes - NEW Plate Current Matched Quad - Current Production Tung-Sol 6L6GC

McIntosh MC30 Owners Manual

Please see our photos or the above manual for full technical specifications and dimensions.

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.

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.