McIntosh MC2505-2

All pre-owned product is tested in our service department and have been passed for sale... and comes with a 90 day warranty!

In nice condition. A few scratches on the autoformers on top and on the back panel. Last image are the full specs.

Original box and packing are NOT included, so this is LOCAL SALE ONLY... BUT If you want us to ship this to you, please contact us if you would like to purchase at an additional cost (approx $100 plus shipping for the carton ONLY), a McIntosh factory box to safely ship it in. We will advise lead time and final price for the box at that time. This is the ONLY was we ship this unit because of the glass front.

Circa 1967-1977. We are an authorized MAC dealer. This amp sounds amazing!

When it was introduced it was the FIRST solid state amp they ever made. This is the "-2" reversion - only real differences from reg version is that the meters do not have a bezel and are mounted against the glass, and the Meter Range switch for the MC 2505-2 was opposite that of the MC 2505 and ranged from -20 to OFF.

The McIntosh MC2505 is a solid state power amplifier with a maximum power output of 100 watts RMS continuous 50 watts per channel operating simultaneously, into 4 ohm, 8 ohm, or 16 ohm loads.

From the manual:  Technical description:

A two stage preamplifier with three transistors in each channel increases the input voltage 16 dB. There are 13 transistors in each power amplifier section. The two stage preamplifier is fed to a pair of matched transistors arranged as an emitter coupled amplifier with two inputs and one output. The signal from the preamplifier section connects to one of these inputs. Both AC and DC negative feedback are applied to the other input. This large quantity of feedback is used to reduce noise and distortion. The signal is then fed to a voltage amplifier. The voltage amplifier is followed by two driver transistors.

The output section is arranged as a series push-pull amplifier. The power transistors used in the output section of your MC2505 are selected for their high power dissipation capability, wide frequency response, and large "safe operating area." In addition, each power transistor is given four separate tests before it is put in your MC 2505. This additional testing makes sure the MC 2505 will deliver its rated power from 20 to 20 kHz with low distortion and complete reliability.

The power transistors are mounted on oversized anodized heat sinks. The heat sinks assure that under normal operation the transistors will operate at a low temperature. If temperatures in-crease due to a shorted speaker, or restricted ventilation, an auto-matic temperature sensing device turns off the MC2505. The device operates automatically at a preset temperature. The MC 2505 will turn on again when the temperature has returned to normal limits. This additional feature gives your MC2505 complete reliability under the most extreme operating conditions.

The output stages are matched to the load by the Mclntosh auto-former. The Mclntosh autoformer is carefully wound using Mclntosh trifilar winding and interleaving techniques. Trifilar winding and interleaving gives the transformers exceptional bandwidth. The autoformers properly match the power transistors to 4, 8, and 16 ohm loads at all audio frequencies.

The use of the Mclntosh designed trifilar autoformer makes the Mclntosh solid state amplifiers the only amplifiers that deliver FULL POWER AT ALL SPEAKER IMPEDANCES. You have not been power penalized for your choice of loudspeakers when using the Mclntosh MC2505. Another of the advantages of the autoformers is the 25 volt output for a constant voltage distribution system. With the MC2505 several sets of speakers can be operated independently throughout your home.

To further insure reliability a special power output SENTRY MONITORING CIRCUIT prevents failure of the power output transistors due to excessive mismatch of the output. When your MC2505 operates normally the SENTRY MONITORING CIRCUIT has no effect on signals passing through the power amplifier. If the power dissipation should rise above normal operation, the SEN-TRY MONITORING CIRCUIT restricts the drive to the output transistors. The SENTRY MONITORING CIRCUIT acts instantane-ously for any input signal or load combination. This arrangement assures complete circuit reliability. Only Mclntosh gives you this degree of protection.

There are three separate power supply sections. One positive and one negative high current supply is used for the output stages. The other positive supply is used for the driving amplifier stages. All supplies are full wave and use silicon rectifiers. Adequate filtering is used to assure an absolute minimum of hum. The power output stage filter capacitors have very high capacity, which allows full power output below 20 Hz. The power transformer is generous in size and runs cool, even under heavy use.

Highlights of the specs:

Harmonic distortion is less than 0.25% at rated power output from 20Hz to 20,000Hz.

Frequency range at rated output both channels; +0, 0.025dB, 20Hz through 20,000Hz.

Damping factor: 10.

Input sensitivity: 0.5V.

Signal to noise ratio: 90dB.

Speaker load impedance: 4Ω to 16Ω

Input Impedance: 200k. He

Headphone Impedance: 4 to 600 ohms.

Sentry Monitor.

Autoformers.

Size: 5-7/16"H x 16"W x 13"D.

Weight: 38 lb; 60lbs w/ shipping carton.