McIntosh MC301 Monoblock Amplifier Pair - Quad Balanced - Free Freight Shipping

Free Shipping on Most Electronics - Excludes Speakers and Items Requiring Freight - Contiguous U.S. Only

General:
The MC301 is an impressive monoblock amplifier from McIntosh, delivering 300 watts per channel into 8, 4, and 2 ohms loads. This consistent power output is made possible by McIntosh’s famous Autoformer technology, built into each monoblock.

Standout features include balanced XLR and single-ended RCA inputs, a slim and minimalist chassis design, power control support, and big beautiful blue VU meters.

This is the first MC301 pair we’ve offered here at SkyFi, and we are impressed. These amplifiers offer exceptional performance for their price point. We had them connected to a pair of Klipsch La Scala's and they sounded awesome across multiple music genres.

Included with the amplifiers are their original McIntosh double-shipping cartons and owner’s manuals.

Shipping Notes:
To ensure these arrive safely, both MC301s will ship in their original McIntosh cartons, securely wrapped and strapped to a pallet, and sent via truck freight anywhere within the contiguous 48 U.S. states at no additional cost (a value of up to $600, depending on location).If you're  outside this area please contact us for a freight quote, as we routinely ship worldwide.

SkyFi Cosmetic Notes:
Light marks are present on the end caps and top covers. Some very light cloudiness to one the the front glass faceplates.(not visible when switched on) Overall the condition is great.

Brand Background:
McIntosh Laboratory is an American manufacturer of handcrafted high-end audio equipment based in Binghamton, New York. The company was founded in 1949 by Frank McIntosh. The company designs and produces audio amplifiers, stereo tuners and other consumer electronics products.

Ownership:
Single Owner

Connections:
XLR, RCA, Power contol, IEC Power

General Sound:
Smooth, uncolored, undistorted natural and clean

MSRP: $5,000 per unit

Cosmetic Condition:
8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top.. See our detailed rating description here.

Working Condition:
Working perfectly and tested in our lab and listening room.

Included:
Units, Boxes, Manuals, Power cords

Packing:
Original Manufacturers Packing

Specs:
- Power Output: 300 watts
- Frequency Response:
- 20 Hz – 20 kHz (+0 / −0.25 dB)
- 10 Hz – 100 kHz (+0 / −3.0 dB)
- Total Harmonic Distortion: 0.005%
- Signal-to-Noise Ratio:
- −95 dBA (balanced)
- −93 dBA (unbalanced)
- Dynamic Headroom: 2 dB
- Output Impedance: 2, 4, or 8 ohms
- Damping Factor: 40 or greater
- Input Impedance: 22 kΩ (balanced or unbalanced)
- Input Sensitivity:
- 3.4 V (balanced)
- 1.7 V (unbalanced)
- Voltage Gain:
- 23 dB (2 ohms)
- 26 dB (4 ohms)
- 29 dB (8 ohms)
- Protection & Technologies:
- Sentry Monitor
- Power Guard
- Quad Balanced™
- Autoformer

Dimensions - Each Monoblock:
17-1/2″ (44.45cm) x 6″ (15.24cm) (including feet) x 21″ (50.8cm) (including front panel and cables)

Weight - Each Monoblock:
67 lbs.

Link to Manual:
Click Here

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Speaker Cables - Better

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

Testing Process:
We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.

If the amplifier passes visual inspection, we move on to a controlled power on sequence using a Sencore safety analyzer to monitor current draw in real time. Once the amplifier is determined to be safe to operate, we connect it to full AC mains for function and power testing. We connect the speaker outputs of the amplifier to a Sencore PA81 Power Analyzer which acts as a dummy load, DC offset monitor, and oscilloscope interface. We start with a low level 1 KHz test signal at the amplifier's input and slowly increase its amplitude while monitoring the output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping.

At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance. If the device under test has both balanced and single ended inputs they are both tested at this time.

We finish off the bench evaluation with a 1 KHz square wave check and a 20 Hz to 20 KHz sine sweep to assess the amplifier's frequency response characteristics.

This battery of tests will usually reveal if the amplifier has any issues that need further attention.

Before the device leaves the bench, we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics.

If the unit passes all of these tests it is moved to our long term testing rig where we simulate real word operating conditions for 6-8 hours minimum. This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when the unit has fully come up to temperature.

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect resistors and other passive components for signs of overheating. If tube arcing has occurred in the past we can usually spot discoloration on the output tube sockets. On vintage units we often spot check select capacitors for value and ESR.

If the amplifier passes visual inspection, we move on to a full test of all of the tubes. We use a modern Amplitrex AT-1000 Professional Tube Tester which is capable of testing both emission and Gm with a high degree of accuracy.

We document the results of each tube and replace any weak or suspect tubes before proceeding.

When we power on tube amplifiers for the first time we usually use a variac and current limited AC supply and slowly raise the voltage up to nominal mains level while monitoring plate, screen, filament, and negative bias supply voltages where applicable.

If everything is in order we feed a low level test signal into the amplifier’s input and monitor its output on an oscilloscope across an 8 ohm dummy load. At this point we are just looking to verify basic function and confirm that the output transformers are not damaged.

Once we have verified that the amplifier is safe to operate, we connected it to full mains power. For fixed bias amps we set the bias to manufacturer spec. For cathode biased amps we monitor the plate to cathode voltage to determine if the output tubes are operating in a safe range. Once the output section is verified we move onto bench evaluation.