The Perfection of McIntosh Amplifiers


McIntosh has been making amplifiers for a long, long time since 1949 infact, when the company was first incorporated as Mcintosh Engineering labatory and moved from Washington D.C to Silver Springs Maryland. However, the seeds were planted as far back as 1942 when Frank McIntosh started a small company consulting on radio station design and sound systems. He was not satisfied with the quality of the audio amplifiers around at the time, so he invented one that gave high power with low distortion. Then in 1946, McIntosh recruited Gordon Gow, who was young but a brilliant engineer, and was pivotal in making his dream real. What they came up with was called the McIntosh 50W1 Unity Coupled Amplifier. It delivered 50 watts of power with less than 1% distortion in the 20 Hz to 20,000 Hz range. So McIntosh, the company arrived in the world with a bang.

Since its inception Mcintosh has been a consistent innovator in amplification. Seen by many as its greatest achievement was the 1967 introduction of the MC2505. It was the primary separate solid state power amplifier made by McIntosh. It was a huge leap in amplifier history and was the forerunner of many of the features still used in the amplifier world today. Among its list of many firsts was an all-glass front panel, Sentry Monitor circuitry, illuminated output level meters, autoformers and panloc mounting. The autoformers of the MC2505 were a totally new idea in McIntosh transformer design history.


Although when they were bought by Clarion (maker of car hi-fi products) in 1990 the same year Frank Mcintosh passed away, it was predicted by some that the quality would drop but of course that did not happen. After all, why would a company like Clarion spend such big money acquiring such a great brand to let standards fall. Simply put McIntosh amplifiers are still making some of the best amplifiers on the globe. Not much has changed in the McIntosh world since its inception, with many of the amplifiers Looking like they came from the 60s. Take for example the with the MC352 with its classic blue meters and glass faceplate,this really is a big amp in all ways—size, weight, and power.


One thing that makes McIntosh amplifier designs very different from others is the use of output transformers, their range includes the MC2102, MC2000, MC275 and the MC602 Mcintosh Amplifier. The McIntosh Amplifier MC-602 is a 600 watt rms per channel, two channel power amplifier, and weighs around 70 kgs. It has 24 output transistors per channel, a 1.5 kVA toroidal transformer, four (two per channel) 27,000 µF capacitors, that has 70 Volts, for 265J of energy storage. It can output 10w per channel in Class A, and the rest in Class A/B. 35 dB of negative feedback are used. This Mcintosh amplifier is fully balanced from input to output. This baby retails at $8k and sounds like heaven, enough said.


In most conventional tube amplifiers, they take power only from the plates of the output tubes. In the McIntosh Amplifier circuit half the power it taken from the plates and half from the cathodes, drawing the power from both sides of the tub.


Now, the patent on the McIntosh Amplifier circuit expired a long time ago, so in theory any other manufacturer is free to copy it. However that would mean they would also have to copy the specially wound output transformers .This is not easy as one of the many unusual if not unique facts about McIntosh Amplifiers is that it winds its transformers in-house. To implement the circuit three transformer windings are needed one more than the usual two. 2 primaries and of course a secondary. The two primaries are spun bifilar, that means that two strands wound together, for a close, turn-by-turn coupling. Which naturally gives it the name - unity-coupled output circuit. The cathode winding gives almost immediate local feedback, which results in reduced distortion at extremes of frequency in Mcintosh Amplifiers.


In 1962 McIntosh began what became probably one of the most successful as well as the longest running marketing campaigns in the Consumer Electronics industry known as ‘The McIntosh Amplifier Clinic’. Whilst they believed that Mcintosh were "Still the Best" they needed to come up with a solution to prove that to the consumer. This was done by testing amplifiers in stores, with shoppers there to witness they could demonstrate just how high the quality was. David H. O'brien may be the most associated man with McIntosh outside of Gordon Gow and of course Frank Mcintosh. He tested huge numbers of amplifiers all over The US and Canada for almost 30 years. You can read all about his story in the "The McIntosh Amplfier Clinics" also written by him.


McIntosh Amplifiers are undoubtedly a brand of incredible quality which you can rely on time and time again. Click on the McIntosh link on the left hand menu to see a wide range of McIntosh Amplifiers with some great prices.