What is it about McIntosh?

[MakeMineVinyl]

No it isn’t. It is finding out the customer wants or needs.

Whatever.

 

[Tom C]

No it isn’t. It is finding out the customer wants or needs.

Wouldn’t the world be awesome if this were true? Unfortunately, the performance review is instead focused on sales results.

 

[rwortman]

Whatever.

When is the last time you bought something because a marketing person told you you wanted it. Note, marketing and advertising are not the same thing. From the American Marketing Association web page:”In basic terms, marketing is the process of identifying customer needs and determining how best to meet those needs. In contrast, advertising is the exercise of promoting a company and its products or services through paid channels.”

It is one of the irritating arrogances of this forum that people here think they purchase rationally and everyone that purchases things they disapprove of is a uneducated dweeb that falls prey to advertising.

 

[rwortman]

Wouldn’t the world be awesome if this were true? Unfortunately, the performance review is instead focused on sales results.

And you get sales results by building what people want.

 

[Doodski]

And you get sales results by building what people want.

... and also by offering new technology that they will use and like even if they have never seen the new tech before. Don't short change the results possibilities.

 

[rwortman]

And if you build new tech they don’t want, you go broke. The great marketing people will see a need that no product currently fills and beat everyone to the punch.

 

[Tom C]

When is the last time you bought something because a marketing person told you you wanted it. Note, marketing and advertising are not the same thing. From the American Marketing Association web page:”In basic terms, marketing is the process of identifying customer needs and determining how best to meet those needs. In contrast, advertising is the exercise of promoting a company and its products or services through paid channels.”

It is one of the irritating arrogances of this forum that people here think they purchase rationally and everyone that purchases things they disapprove of is a uneducated dweeb that falls prey to advertising.

Well, I’m not perfect, but I do try to do the best I can to get the best value for my money.
It’s a fact of life that I want to pay as little as I can for your hard work, and you try to pay as little as you can for mine. This is not to be lamented. It is to be celebrated, for it is our strength. This is our culture and part of our heritage. It is part of what makes us strong. Pretending otherwise is to the detriment of us all.

 

[MakeMineVinyl]

And if you build new tech they don’t want, you go broke. The great marketing people will see a need that no product currently fills and beat everyone to the punch.

That all goes to hell though in the world of audio marketing with its snake oil and voodoo, fueled by reviewers and dealers. You seem to think that the audio world conforms to that idealized world of marketing in the textbooks. Perhaps in other industries, but not in audio.

 

[blueone]

The measurements Amir takes at most are into 4 and 8 ohm resistors. Audio amplifiers are not purchased to heat resistors with ultra low distortion AC.

I'm missing your point. Amir's tests of power and distortion into 4 ohm and 8 ohm loads tells you a lot about how the amplifier responds to both low and high impedance speakers. Most speakers seldom present a load lower than 3 ohms (though some do, but not many), and amplifiers have an easier time being consistent voltage sources at higher impedances, so measuring at, say, 16 ohms seems less than revealing. Or are you wondering about something like highly capacitive loads from speakers? Are you implying that autoformers buffer the output stage transistors from speakers which present loads with demanding phase angles at low impedance in frequencies that need a lot of power (like the bass octaves)?

 

[Salida]

Interesting discussion. Couple of points I don’t think have been mentioned.

Autoformers, (love ‘em or hate ‘em) allow McIntosh to implement their quad balanced topology, even in a tube amplifier, the MC 2301. Quad balanced is two differential fully balanced amplifiers run out of phase, who’s outputs are then electronically summed in phase in multiple primaries of the output transformer. Individual amplifier nonlinearities cancel out, reducing distortion and noise.

McIntosh service is excellent. I used it recently and found the telephone support and knowledge of Chuck Hinton and others to be exemplary. You can buy manuals and get support for most anything they have ever made.

McIntosh cost of ownership is very low due to high resale values. I buy most of my stuff used and have made money on every McIntosh amplifier or preamp I have owned and then sold to upgrade. That’s negative cost of ownership! It doesn’t hold for any of their source equipment or HT gear, though.

They have some other engineering niceties.

R-core transformers help reduce the impact of emi and rfi on the incoming power lines by having physically separate transformer primaries and secondaries with very low capacitive noise coupling.

All modern McIntosh gear uses vacuum-sealed reed switches with Rubidium contacts for input selection and resistive ladder stepped attenuators for volume controls. So no noisy pots or input switches. Ever.

If you are looking for oil-filled capacitors wound on the thighs of virgins you won’t find any of that here. Just well designed gear with some unique attributes that is well supported and holds its value over time.

 

[KMM]

In 2004 I bought a McIntosh MA6900 in Montreal IIRC for some 6500 CAD$ and sold it in very good condition in Germany in 2020 for €3500.
No repairs, defects or issues whatsoever.
Try that with any other brand

 

[blueone]

Autoformers, (love ‘em or hate ‘em) allow McIntosh to implement their quad balanced topology, even in a tube amplifier, the MC 2301. Quad balanced is two differential fully balanced amplifiers run out of phase, who’s outputs are then electronically summed in phase in multiple primaries of the output transformer. Individual amplifier nonlinearities cancel out, reducing distortion and noise.

How exactly do autoformers support the quad balanced topology? There are other amps which use dual-differential output stages and don't use output transformers. The Emotiva XPR-1 comes to mind.

 

[Salida]

In a conventional dual differential design, the outputs of both amplifiers are in series, which doubles the voltage swing and output impedance. In this case the noise components are also in series and so increase 3 dB along with the signal. Most of these amps can drive 4 ohm loads but struggle as the impedance drops below that point. Usually lots of output devices are needed to maintain SOA.

In the McIntosh design, the outputs of the two amplifiers are applied to separate primary windings and appear effectively in parallel in the secondary. This allows a better match to the SOA of the output devices in the amplifier and reduces the noise by 3 dB wrt the signal since the noise is uncorrelated and the signal is.

That’s it, nothing earth shattering.

 

[blueone]

In a conventional dual differential design, the outputs of both amplifiers are in series, which doubles the voltage swing and output impedance. In this case the noise components are also in series and so increase 3 dB along with the signal. Most of these amps can drive 4 ohm loads but struggle as the impedance drops below that point. Usually lots of output devices are needed to maintain SOA.

In the McIntosh design, the outputs of the two amplifiers are applied to separate primary windings and appear effectively in parallel in the secondary. This allows a better match to the SOA of the output devices in the amplifier and reduces the noise by 3 dB wrt the signal since the noise is uncorrelated and the signal is.

That’s it, nothing earth shattering.

I'm not an EE, so perhaps you can expand on your explanation a bit. In the case of dual differential outputs, the input signal is divided into two phases, either with a phase splitter, or by using a balanced input signal, where the phases are already split. The two phases are processed in parallel by different sides of the differential pair, and the phases are combined at the speaker terminals. How are the amplifier stages connected in series?

 

[mhardy6647]

That all goes to hell though in the world of audio marketing with its snake oil and voodoo, fueled by reviewers and dealers. You seem to think that the audio world conforms to that idealized world of marketing in the textbooks. Perhaps in other industries, but not in audio.

It's all about influencers -- which is a pretty generic case, methinks.

 

[Salida]

Here is another way of looking at it. You have two separate and complete amplifiers, one operates in phase with the input signal, the other operates 180 degrees out of phase with the input signal. Both amplifiers are fully balanced as well. The load is connected to the output of each amplifier, thus the outputs are in series with each other and the load. Not sure how else I can explain it.

 

[egellings]

Marketing attempts to generate a need where none existed before.

 

[blueone]

Here is another way of looking at it. You have two separate and complete amplifiers, one operates in phase with the input signal, the other operates 180 degrees out of phase with the input signal. Both amplifiers are fully balanced as well. The load is connected to the output of each amplifier, thus the outputs are in series with each other and the load. Not sure how else I can explain it.

Sorry, but I'm still confused by what you're saying. I thought the potential 4x power increase you get from bridging amplifier channels was because there's no reference to ground, which results in a potential doubling of the output voltage, not because the amplifier channels are in series. When I think of something being electrically in series, I think of a case where there are two resistors connected together so the output of the first is connected to the input of the second. Apparently I'm being dense and not seeing the big series topology picture here.

I do understand your statement about differential amplification stages introducing a 3db increase in noise, because noise is random. And I remember that ATI said they eliminated the balanced bridging in the input stage of their 6000-series amps, which reduced noise by 3db compared to their previous 3000 series designs. I assumed when I read about it that the reduction in distortion they gave up was a smaller price to pay than the reduction in noise.

The only advantage I've ever seen to autoformers is that the impedance matching they provide to the output stages essentially allows you to measure 2 ohm power into an 8 ohm load, compared to conventional amplifiers without output transformers.

 

[TjindarSingh]

Tired both the ma252 and 352 .

The 252 I didn't like at all, but the 352 was a bit of fun factor in it.

 

[Salida]

I think of a case where there are two resistors connected together so the output of the first is connected to the input of the second. Apparently I'm being dense and not seeing the big series topology picture here.

That’s it. Output of the + amplifier (and it’s output impedance, noise, etc) in series with the speaker load, in series with the output of the (-) amplifier. No ground reference.

For a given speaker load impedance, double the voltage, 4x the power, double the noise, and double the output impedance.

You are correct, the advantage of the autoformers in this case is that the individual amplifiers see a more reasonable load impedance.