McIntosh MC2505-2 Stereo Power Amplifier

Circa 1970-1971 • McIntosh Walnut Cabinet • Panloc Mounting System • Excellent Condition

For sale is a very clean circa 1970-1971 McIntosh MC2505-2 stereo power amplifier, complete with a McIntosh walnut equipment cabinet and Panloc mounting system.

This amplifier has been used in a smoke & vape-free professional recording studio environment and has been very well cared for. It is fully functional with no known issues and has always sounded excellent.

I am only selling it because I have moved to active speakers and simply can’t justify keeping an amp around purely because it looks cool - although the MC2505 makes a pretty convincing argument for doing exactly that.

A Classic McIntosh

Manufactured during the early solid-state era of McIntosh, the MC2505 is one of the company’s most recognizable and historically important amplifiers.

The MC2505 is particularly significant for introducing the illuminated blue power meters that went on to become one of the defining visual signatures of McIntosh equipment.

Beyond its appearance, the MC2505 incorporates much of the engineering that made classic McIntosh amplifiers so highly regarded.

Its McIntosh-designed output autoformers allow the amplifier to deliver its full rated output into 4, 8, or 16-ohm speaker loads rather than optimizing the output stage for only a single impedance. This design became a hallmark of McIntosh solid-state power amplifiers.

The amplifier also incorporates McIntosh Sentry Monitor output protection along with thermal protection for the output stage.

Another standout feature is its sophisticated peak-reading meter system. Rather than acting as simple slow-moving VU meters, the MC2505 meters were designed to respond to short-duration musical peaks and hold the indication long enough to make those peaks visible.

Combined with the illuminated glass front panel, chrome chassis, large blue meters and substantial construction, the MC2505 established much of the visual and engineering language associated with classic McIntosh power amplifiers.

Circa 1970-1971 Production

This amplifier is the later MC2505-2 version.

During photographing, the amplifier was found to retain what appear to be its original power-supply capacitors. One of the large GE filter capacitors carries a date code corresponding to the 27th week of 1970, which, together with the MC2505-2 chassis configuration, supports an estimated production date of approximately 1970-1971.

I do not have service records from before my ownership, so I am not representing it as completely untouched or fully original internally. However, the visible power-supply components appear period-original and consistent with the age of the amplifier.

Ownership & Service History

I purchased the amplifier in 2021. The previous owner did not have any service records, and I have not had it serviced during my ownership because it has performed flawlessly since the day I got it. It has always been quiet, stable and excellent sounding.

McIntosh Walnut Cabinet & Panloc System

The amplifier is housed in a McIntosh L52/L52A-style walnut equipment cabinet and includes the McIntosh Panloc mounting hardware.

To the best of my knowledge, this is the cabinet that has always been with the amplifier and is likely original to it.

The Panloc system securely locks the amplifier chassis into the cabinet while allowing it to be released and removed from the front.

The walnut cabinet is in very nice overall condition with normal age-related wear visible in the photos. It presents beautifully with the amplifier and really completes the classic McIntosh look.

Specifications

Specification

Details

Type

Solid-state stereo power amplifier

Power Output

50 watts RMS continuous per channel, both channels operating

Rated Speaker Impedances

4, 8 and 16 ohms; separate output terminals for each impedance

Rated Power Band

20 Hz - 20 kHz

Frequency Response

20 Hz - 20 kHz: +0 / -0.25 dB
10 Hz - 100 kHz: +0 / -3 dB

Total Harmonic Distortion

0.25% maximum from 250 mW through rated 50-watt output, 20 Hz - 20 kHz, both channels operating

Intermodulation Distortion

0.25% maximum for instantaneous peak outputs up to 100 watts per channel

Noise & Hum

90 dB below rated output

Input Sensitivity

0.5 V

Input Impedance

200 kΩ

Damping Factor

14 at 4 ohms; 27 at 8 ohms; 13 at 16 ohms

Output System

McIntosh autoformers with dedicated 4, 8 and 16-ohm outputs

Protection

McIntosh Sentry Monitor output protection; thermal protection on output transistor heat sinks

Meters

Dual illuminated peak-reading output power meters

Additional Features

Individual left and right gain controls; front-panel headphone output; speaker on/off switching; McIntosh Panloc mounting system; 25-volt distribution output capability

Condition/Recap

This is a very clean example that has spent its recent life in a smoke/vape-free recording studio.

The glass, meters, controls, chrome chassis and cabinet all present very well. It is operating properly with no known issues.

Selling only because my studio has transitioned to active speakers.

Please review the photos carefully for the exact cosmetic condition. I am happy to answer any questions about the amplifier.