william.keith
Super Member
The MC205 and MC207 do not have autoformers and they also provide a constant impedance match.
Autotransformers - why does McIntosh use them?
- Thread starter jjay
- Start date
I don't hear any negatives as compared to numerous amps I've had before. If anything, the highs come across as silky smooth without loosing any resolution or robbing the system of "air" and "ambiance" and the bass is very musical, so I don't think the autoformers cause any problems at either end of the audible frequency spectrum. I also don't think the MC501's would have won so many awards over the years if the autoformers did something negative to the sound.
I am not familiar with those products and I don't know what the 4/8 ohm switch presents to the audio path. I would be surprised if there is not a sonic penalty to pay for that feature. :scratch2:
Jim, I think you would have to draw your own conclusions as to the affect on sound quality from the excellent reviews that McIntosh have achieved in the last few years from their Autoformer desigs.....they are clearly technically very proficient at making audio frequency transformers having done this since the late 1940's.
It seems a peculiar fact of modern high-end equipment reviews that something about audio transformers (auto or otherwise) seems to change the perceived quality of sound for the better - think of reviews of passive pre-amps relying on transformers or of moving coil step-up transformers and you will be on the right track.
Why this should be so is a mystery and I am sure there are plenty of possible explanations, but I would hazard a guess that this is why the 'sound' of Autoformer equipped amps is well-received - of course McIntosh would argue for sound engineering reasons for using them, but this may not be the whole story....
I wouldn't therefore worry too much about Autoformers having a negative affect on sound quality:yes:
cheers, W.
It seems a peculiar fact of modern high-end equipment reviews that something about audio transformers (auto or otherwise) seems to change the perceived quality of sound for the better - think of reviews of passive pre-amps relying on transformers or of moving coil step-up transformers and you will be on the right track.
Why this should be so is a mystery and I am sure there are plenty of possible explanations, but I would hazard a guess that this is why the 'sound' of Autoformer equipped amps is well-received - of course McIntosh would argue for sound engineering reasons for using them, but this may not be the whole story....
I wouldn't therefore worry too much about Autoformers having a negative affect on sound quality:yes:
cheers, W.
jjay
Member
Thanks Wolfcub,
I was just puzzled by the opinions of people on other forums about autotransformers negatively affecting sound quality of McIntosh SS Amplifiers, Not tube amps like the 275. Like most people, I made my decision by my own ears, but I just don't hear what they are talking about. I am very happy with the MC252 ss amplifier but comments about autotransformers got my curiosity up.
thanks again,
Jim
Jim, is the 252 your very first amp and you don't have any frame of reference? :scratch2: Most of the people who post negative comments about McIntosh amps have never even owned one and many have not even heard one. You know how that goes, everyone is entitled to their opinion and opinions are like a-------s, every body's got one.
These are the same people that will argue which amp or preamp is better today only to acquire something else tomorrow and swear it's the best sounding amp ever, until the next day.... 
One thing is for sure, this forum has some of the most loyal fans of the same brand gear and for sure people tend to hang on to their gear much longer than anywhere else I have seen. There's got to be a good reason for that. :yes:I'm always amazed at the level of animosity directed against McIntosh. On another forum I had a couple of guys telling me they were in the same class as Bose.
I'd rather own Bose stock than McIntosh .... stock - man can those guy market.
I can't believe the prices they charge for what's essentially plasticy, lightweight (in more ways than one) equipment. But my hat's off to them for their marketing skills.
Alberto
vintage_tube
Vacuum Tube Passion
Audiophiles shouldn't knock Bose too hard -- they laid the first layers of asphalt road I'm presently on (and probably more than anyone can count). Bose was a big marketer of speakers and amps (Bose 1801; which I owned- 256 watts p/c) to the military overseas (my first 901 series I's were around $300 a pair & the amp was a staggering $735--both military pricing).
This has NO bearing on their marketing gimmicks and deceiving demos they use to sell their stuff today. Talk about unethical.
Gaucho1
Well-Known Member
My first speakers that I purchased were Bose too, until I bought a pair of JBLs for half the price that blew them away.
goldear
Certifiable Audio Junkie
This explanation is so far off-base to be in a completely different ball-park. :headscrat No transformer can compensate for impedance variations as a function of frequency.
It simply allows one to potentially provide a better match for speakers loads with an average impedance that is either significantly higher or lower than 8 ohms.I thought the Mc patent has expired? I thought the real reason others can’t compete with MC designs is that to make an autoformer requires considerable skill to design and match to the particular amp. Easy for Mc, very costly for others to get right I suspect.
mhardy6647
Lunatic Member
This explanation is so far off-base to be in a completely different ball-park. :headscrat No transformer can compensate for impedance variations as a function of frequency.
That's consistent with what I thought (and mentioned earlier). Bear in mind that there's another class of hifi iconoclasts who build output transformerless vacuum tube amplifiers, because of hysteresis effects, etc. in output iron that (some folks hold) mean that an OPT always does some harm. Examples:
http://www.transcendentsound.com/
http://www.atma-sphere.com/ (EIDT: the Atma-sphere site isn't loading at the moment...)
I prefer to think of it thus: it is perfectly possible to build a good output transformer or autoformer, but it's danged expensive, and the quality of raw materials available today just isn't up to what was inexpensive and readily available 40 or 50 years ago.
nsgarch
McStatic
I doubt there was ever a patent on the autoformer design -- it certainly WAS NOT a McIntosh invention, nor is it very hard to build one. The McIntosh patent you're all thinking about is the Unity Gain Circuit which, of necessity required two (bifilar) or three (trifilar) parallel windings on the primary side of the output transformer, and difficult to build one properly. I don't think Mac held a patent on those transformers either, although they developed proprietory techniques for making them with low distortion. And in fact they still make them 'in-house', as most of you know.
An autoformer is simply an impedance matching transformer with one winding and several taps. Paul Speltz has been marketing them for some time now with great success. You can get a clear and simple explanation of their design and application at his website: http://www.zeroimpedance.com/ :thmbsp:
mhardy6647
Lunatic Member
I think McIntosh may have had a patent on their trifilar winding topology.
Yeah, I was going to chime in on the similarities -- and differences -- of autoformers vs. transformers. Nothing magical about the former relative to the latter, except that the former are nonisolating -- which can have some potential repercussions in case of shorts (in the case of an output autoformer) or electrocution (in the case of a power supply autoformer, such as a Variac) :-(
http://en.wikipedia.org/wiki/Autotransformer
Yeah, I was going to chime in on the similarities -- and differences -- of autoformers vs. transformers. Nothing magical about the former relative to the latter, except that the former are nonisolating -- which can have some potential repercussions in case of shorts (in the case of an output autoformer) or electrocution (in the case of a power supply autoformer, such as a Variac) :-(
http://en.wikipedia.org/wiki/Autotransformer
dnewma04
The Healer
It would be no more difficult or costly for other mfgs to use high quality autoformers. Mc addressed a real world problem of making their amps operate well using a wide variety of speakers. Other mfgs want to simplify things and don't use them because of a theory that less is better. Mc amps will work better with a wider variety of speakers because of the autoformers, but I suspect that there are going to be a few other amps that will always outperform Mcs on particular speakers. You may find that electrostats, planar magnetics, cone/domes, horns all sound great on a McIntosh amp whereas some other amp (insert other highend amp) will stomp all over the mc with electrostats, equal it on cone/domes and planar magnetics and sound like screetchy hell on horns. (just a random example).
IOW, Mcs will probably have a broader range of appeal to the masses, but there is going to be that small group of people that will never find a mc adequate sounding.