McIntosh's Most Powerful 2CH Amp Ever Unveiled!

[Verdinut]

So "quad balanced", is that the same design as the Quad amplifiers @TLS Guy has high regard for? If so, where you at, doc?? I'd be curious to read your take on this one.

Quad is just a brand name for the British current dumping power amps.

 

[Pogre]

Quad is just a brand name for the British current dumping power amps.

I knew that was the brand name. Didn't know if their design was like "kleenex" and that's what everyone calls it now or something.

So what is "quad balanced" then? Just some marketing?

 

[Verdinut]

I knew that was the brand name. Didn't know if their design was like "kleenex" and that's what everyone calls it now or something.

So what is "quad balanced" then? Just some marketing?

I couldn't tell. You could probably get more info by contacting McIntosh. If their marketing people run the outfit, then expect to get some obscure bullshit.

 

[ski2xblack]

@Pogre The Quad amps have nothing to do with McIntosh's terminology, which concerns balanced amp circuits in class AB amps. Quad amps, on the other hand, are an innovative design that inherently lacks the crossover distortion that bedevils all class AB amplification (and which has been effectively dealt with in conventional modern AB amps, fwiw), without the poor efficiency and heat a traditional class A amp produces. Unlike a class AB amp, the Quad current dumpers use a low power class A control amp tied to a high power class B amp to provide the current in a clever feed-forward error correction circuit. Worth a Google search if you want to dive deeper. To learn about amp classes, balanced circuits, etc, try this link. And look at the first attachment on this post by TLS for the nitty gritty on Quad current dumpers.

 

[Edgar Betancourt]

Quad balanced means that the amplifier uses dual balanced circuits, one for each channel. Aside from the common power transformer its essentially a dual mono AB design that utilizes negative feedback to eliminate essentially all noise and distortion from the audio signal (>-120db!). Furthermore, and exclusive to MC, it uses output transformers to match its power regardless of speaker impedance be it 2, 4, or 8 ohms, thus it provides the same 450W at the same distortion rating of <0.005%, from 20-20K hz. No other stereo amp can match those specs and the audiophile monoblocks that can can be counted with one hand, 2 of those are McIntosh too )) Its expensive, big, heavy and some don't like the esthetics, but its the gold standard regardless of price. I'll skip the discussion on output transformers, by simply stating that the proof is in the pudding!

 

[Cjamrr]

Quad balanced means that the amplifier uses dual balanced circuits, one for each channel. Aside from the common power transformer its essentially a dual mono AB design that utilizes negative feedback to eliminate essentially all noise and distortion from the audio signal (>-120db!). Furthermore, and exclusive to MC, it uses output transformers to match its power regardless of speaker impedance be it 2, 4, or 8 ohms, thus it provides the same 450W at the same distortion rating of <0.005%, from 20-20K hz. No other stereo amp can match those specs and the audiophile monoblocks that can can be counted with one hand, 2 of those are McIntosh too )) Its expensive, big, heavy and some don't like the esthetics, but its the gold standard regardless of price. I'll skip the discussion on output transformers, by simply stating that the proof is in the pudding!

 

[Cjamrr]

I listen to the MC462 every time I go to my favorite stereo shop. They hook up all kinds of different amps and speakers all day long. I like the McIntosh stuff. People are buying them. I’m next.

 

[eljr]

$9000.00 Good grief.

Forgive me, I am not an EE, but I still think I would rather have the ATI AT1802 power amp over this thing.

You don’t get the blue meters, but I’ll bet you that I wouldn’t be able to hear the difference between the two anyway.

I’ll take money saved and invest it.

But like you said, then you would not get the blue meters.

 

[Irvrobinson]

Quad balanced means that the amplifier uses dual balanced circuits, one for each channel. Aside from the common power transformer its essentially a dual mono AB design that utilizes negative feedback to eliminate essentially all noise and distortion from the audio signal (>-120db!). Furthermore, and exclusive to MC, it uses output transformers to match its power regardless of speaker impedance be it 2, 4, or 8 ohms, thus it provides the same 450W at the same distortion rating of <0.005%, from 20-20K hz. No other stereo amp can match those specs and the audiophile monoblocks that can can be counted with one hand, 2 of those are McIntosh too )) Its expensive, big, heavy and some don't like the esthetics, but its the gold standard regardless of price. I'll skip the discussion on output transformers, by simply stating that the proof is in the pudding!

Quad-balanced means that each channel has dual differential amplification circuits. So four circuits doing the work of one. While this strategy does theoretically improve the common mode rejection ratio of the amplifier channels, this topology does not exceed (nor probably meet) the distortion and noise performance of some other amplifiers, like the some Hypex-based or Purifi-based class D amps, or the Class AB Benchmark Media ABH2, which uses feed forward error correction. (Admittedly the Benchmark amp has significantly lower power output than the McIntosh.)

The autoformers do appear to be a gimmick. They increase output impedance while reducing output voltage into loads of less than 8 ohms.

These amps are built well with high quality parts, have awesome industrial engineering, but they are not really state of the art.

 

[Edgar Betancourt]

But like you said, then you would not get the blue meters.

In the grand scheme of audio 9k is in effect value oriented audiophile. Amps can run into 100k plus. An amp that can happily drive any speaker made with ease and utter fidelity is a "bargain". BTW damping factor is a superfluous spec anything over 20 is more than plenty. I use mine to drive BW 803 D3, a bottom ported design, the bass is not only impressive, its probably the tightest, fastest and "cleanest" you will ever hear. Since the 803's are the most bass light of the 800 "headed* models I kept the twin DB1's I had for my previous 805. To put it mildly bass in my system emperils my house's structural integrity Not boomy at all its simply that the infrasonic reach and power of all of that approaches artillery levels!

 

[Irvrobinson]

In the grand scheme of audio 9k is in effect value oriented audiophile. Amps can run into 100k plus. An amp that can happily drive any speaker made with ease and utter fidelity is a "bargain".

A $9,000 two channel amp is not a value-oriented product under any circumstances. I do understand wanting the industrial design of the McIntosh, and I suppose people think they need something like 450 watts/ch (Gene, the owner of this site, thinks he does), but there are other ways to get very similar power and performance for less money.

BTW damping factor is a superfluous spec anything over 20 is more than plenty.

20 is low. In this article by Richard Pierce, he's more in the 50 range:

Damping Factor: Effects On System Response

Much ballyhoo surrounds the concept of "damping factor." It's been suggested that it accounts for the alleged "dramatic differences" in sound between tube and solid state amplifiers. The claim is

www.audioholics.com

If you have a speaker that dips to 2 ohms or below, and there are several speakers in this category, you probably want a damping factor that is much higher. Note that the chart on page 2 of the article assumes a speaker with an impedance minima of 6 ohms, which is not common these days. Many speakers I've seen measured on this site and ASR have impedance minima below 4 ohms, and some below 2 ohms.

 

[highfigh]

Damping factor isn't really important at all; 40 is probably good enough, but the reason the damping factor isn't so hot is the use of output transformers (the Autoformers, in McIntosh parlance),as they effectively raise the amp's output impedance, and that lowers the effective damping factor. And in solid state amps output transformers aren't necessary. In McIntosh's case, it's some sort of weird tradition from tube amps where they do serve a purpose. In this amp, IMHO, they're a waste of parts cost.

The use of 'autoformer' isn't just McIntosh parlance- it's used in volume controls for distributed audio and many other applications. It allows using different loads without compromising output power. The specs for the MC1.25 show >40 wide band damping factor and that used to be emphasized more WRT low frequency performance, rather than wide-band, although damping for mids and highs is basically moot.

 

[highfigh]

A $9,000 two channel amp is not a value-oriented product under any circumstances.

That price being considered 'value oriented' is a bit like someone who got the crap kicked out of them in a fight saying "You should see the other guy".

 

[Cjamrr]

But like you said, then you would not get the blue meters.

 

[Cjamrr]

So you’re saying you would sell the MC462 if someone gave you a brand new one, or would you keep it as a prize for yourself.

 

[Irvrobinson]

So you’re saying you would sell the MC462 if someone gave you a brand new one, or would you keep it as a prize for yourself.

Sell. No question.

 

[Edgar Betancourt]

A $9,000 two channel amp is not a value-oriented product under any circumstances. I do understand wanting the industrial design of the McIntosh, and I suppose people think they need something like 450 watts/ch (Gene, the owner of this site, thinks he does), but there are other ways to get very similar power and performance for less money.



20 is low. In this article by Richard Pierce, he's more in the 50 range:

Damping Factor: Effects On System Response

Much ballyhoo surrounds the concept of "damping factor." It's been suggested that it accounts for the alleged "dramatic differences" in sound between tube and solid state amplifiers. The claim is

www.audioholics.com

If you have a speaker that dips to 2 ohms or below, and there are several speakers in this category, you probably want a damping factor that is much higher. Note that the chart on page 2 of the article assumes a speaker with an impedance minima of 6 ohms, which is not common these days. Many speakers I've seen measured on this site and ASR have impedance minima below 4 ohms, and some below 2 ohms.

If you use output transformers its a moot point since you can match the impedance of the speaker! You just hit the nail on the head of why, though not necessary for "general" audio it is sometimes a necessity if your preferred speaker requires it. The output transformers on MCs will drive a 2 ohm speaker at full rated capacity and within distortion specs all day long! It won't even need a fan
Add to that a filter capacitor capacity of 3db and you essentially has a power capacity to reproduce any musical recording with utter ease at any level. Its not voodoo its simple, straightforward, old fashion, electrical engineering. Need power? Make a bigger transformer, add more power transistors and shove in more capacitors. Price, size and weight be damed! The "autoformers" take care of speaker impedance thus the power section always operates well within its thermal limits. You can drive the amp at full power for hours without it ever getting more than a little warm. BTW a nice chunk of the price is in fact esthetics, the glass front, signature meters and steel chassis that can hold the weight of a tank are almost a third of the manufacturing cost. Please note, the only reason they dont make an even more powerful stereo model is that it would require another power cord. As it stands it taxes standard wall electrical circuits.

 

[Edgar Betancourt]

If you use output transformers its a moot point since you can match the impedance of the speaker! You just hit the nail on the head of why, though not necessary for "general" audio it is sometimes a necessity if your preferred speaker requires it. The output transformers on MCs will drive a 2 ohm speaker at full rated capacity and within distortion specs all day long! It won't even need a fan
Add to that a filter capacitor capacity of 3db and you essentially has a power capacity to reproduce any musical recording with utter ease at any level. Its not voodoo its simple, straightforward, old fashion, electrical engineering. Need power? Make a bigger transformer, add more power transistors and shove in more capacitors. Price, size and weight be damed! The "autoformers" take care of speaker impedance thus the power section always operates well within its thermal limits. You can drive the amp at full power for hours without it ever getting more than a little warm. BTW a nice chunk of the price is in fact esthetics, the glass front, signature meters and steel chassis that can hold the weight of a tank are almost a third of the manufacturing cost. Please note, the only reason they dont make an even more powerful stereo model is that it would require another power cord. As it stands it taxes standard wall electrical circuits.

BTW, yes it very expensive, but no one complins about the price of a Buggati when driving at 300mph. Consider a MC as the performance of a Bugatti at the price of a Mercedes and then it starts to make sense

 

[Irvrobinson]

If you use output transformers its a moot point since you can match the impedance of the speaker! You just hit the nail on the head of why, though not necessary for "general" audio it is sometimes a necessity if your preferred speaker requires it. The output transformers on MCs will drive a 2 ohm speaker at full rated capacity and within distortion specs all day long! It won't even need a fan

Since well-designed solid-state output stages for Class A or AB amplifiers have low output impedances, output power would increase as speaker impedance decreases. So I would expect a well-designed 450 watts into 8ohms solid-state amplifier without autoformers to be rated at something like 600 watts into 4 ohms. Nonetheless, I think one can say that with almost any home speaker in even a very large room, a 450 watt RMS per channel amplifier is going to be more than sufficient for full-range speakers. I suspect this is true is even for large sealed subwoofers in real-world use.

Add to that a filter capacitor capacity of 3db and you essentially has a power capacity to reproduce any musical recording with utter ease at any level. Its not voodoo its simple, straightforward, old fashion, electrical engineering. Need power? Make a bigger transformer, add more power transistors and shove in more capacitors. Price, size and weight be damed! The "autoformers" take care of speaker impedance thus the power section always operates well within its thermal limits. You can drive the amp at full power for hours without it ever getting more than a little warm. BTW a nice chunk of the price is in fact esthetics, the glass front, signature meters and steel chassis that can hold the weight of a tank are almost a third of the manufacturing cost. Please note, the only reason they dont make an even more powerful stereo model is that it would require another power cord. As it stands it taxes standard wall electrical circuits.

The capacity of the filter capacitors is moot beyond a certain point, as determined by the efficiency of the rectifier to convert AC to DC (how much smoothing is necessary), the VAC capability of the transformer, and the load generated by the amplifier's output stage. Some amplifiers, like, for example, Krells that can double power output as load impedance halves, do indeed need huge filter capacitors because the charge necessary to smooth the rectifier output at what will be, say, 800 watts into 2 ohms, is greater than the need at 400 watts into 4 ohms. Nonetheless, it is a myth that filter capacitors in linear power supplies can somehow make up for the output VAC limit of the transformer.

 

[eljr]

So you’re saying you would sell the MC462 if someone gave you a brand new one, or would you keep it as a prize for yourself.

how could you sell those beautiful blue meters?