Would McIntosh Auto Transformers affect speaker sound?

Would it cause the speaker not to give the same soundstage or holographic sound that a traditional amp would give? 

yes it would a modern solid state amplifier  doesn't need an autoformer and the device and all of its wire gives you the warm sound of the mc but causes a loss of clarity

No, no affect on dynamic delta, soundstage, or holographic sound unless you run out of power. Otherwise all valve amps using transformers would not have these qualities.

If a transformer is mismatched to the load, slightly less power will be delivered to the load. That’s it. Now there are other things that go on with transformers such as the damping factor being different on different taps, but again, I dont think that pertains to the original question.

Viridian is correct. They have no negative effect on sound, and yes, I have compared transformer coupled Macs against a number of non-transformer coupled competitors and I believe the Mac sounds better. Of course it's a matter of taste as always, but no, they don't affect the soundstage or clarity. 

@roxy54 , @viridian +1, 

If anything, the autoformer allows you to have stable rated power on the selected ohm taps. If you have 2-ohm speakers, use the 2 ohm taps and you will have stable power at 2 ohms. Try that with an amp rated at 8 ohms which can also do 4 ohms, but not 2 ohms. You will lose power. No matter what you do, the amp and speakers need to have synergy regarding the ohm rating. 

This was an extract from a review in Germany for the Mcintosh MC2301 tube amp, which were the first tube Mcintosh product to use the autoformer. 

The power output may change based on which ohm taps are used. This is because the MC 2301 provides taps for 2, 4 and 8 ohms. The output stage is not interested in nominal values, it is influenced by the complex, frequency-dependent "fluctuating load of the connected speaker", the proof is in the pudding. Whatever sounds best is allowed.

Using the 4-ohm taps, the measurement laboratory from Audio.de determined a tight 353 watts with a simulated 4-ohm termination, while the power output at 8 ohms was limited to "only" 271 watts. On the 8-ohm windings of the output transformers, the MC 2301 produced 350 watts into 8 ohms and a satisfactory 154 watts into 4 ohms.

Overall, I think you have more versatility with an amp that provides more than one set of ohm taps. On the other hand, you match the speaker and amp which does have the correct ohm rating for the speaker, then you are okay as well. Where I see that as a drawback, is if the speaker is rated at 8 ohms, but dips to 4 ohms, yet your amp does not have a 4 ohm tap, nor has good 4 ohm performance with the 8 ohm tap. Then, you could run into a mismatch as the speaker dips down deep into the low ohm range. 

Audiotroy please stop giving bad info...   

@audioquest4life

Where I see that as a drawback, is if the speaker is rated at 8 ohms, but dips to 4 ohms, yet your amp does not have a 4 ohm tap, nor has good 4 ohm performance with the 8 ohm tap. Then, you could run into a mismatch as the speaker dips down deep into the low ohm range.

What about a 2, 4, 8 ohm amp like the Yamaha AS-3200 that only has a single pair of taps? I thought a single pair of taps applied to all the ohms the amp is rated for?
 

@viridian + 4

Mike

I am interested in this question. I recently purchased a McIntosh MA9500, which sounds great on my Focal Scala Utopia Evo. I am considering what Amp I want to pair with an on-order set of Wilson Watt Puppies. I originally thought a MC462 + C2800 combo (since I like the sound from the MA9500 and I am sucker for the blue lights). But my dealer is adamant that the autoformers inhibit clarity and engagement, and is pushing the Gryphon Diablo 333 instead. 

ODDFIO YOU ARE WRONG

ALL THE WORLDS BEST SOLID STATE AMPLIFIERS ARE DIRECT COUPLED

GRYPHON, CH PRECISION, BOULDER, T+a, KRELL, DAGASTINO. PASS, CODA VITUS, ETC.

THE ONLY COMPANY IN THE WORLD THAT USES AN AUTOFORMER IS MACINTOSH YOU DONT DESIGN A SOLID STATE AMPLIFIER LIKE A TUBE AMPLIFIER

AS PER LOAD MATCHING WITH A BIG ENOUGH POWER SUPPLY YOU CAN POWER AN ARC WELDER AND PUT POER INO ANY LOAD

And one of the world’s best solid state amplifiers uses autoformers.

About 6 years ago I was considering a Mac for my Maggie's so I called the factory and they recommended against using their autoformer amps with these speakers so I went with with Pass instead which was a terrific match. 

I don’t care what the so called “ audio doctor” audiotroy says about McIntosh.  It is a great, well built, great sounding piece of American Engineering that has a higher resale value than most other brands.  It’s good enough for me and that is all that counts.  

@johnto,

unfortunately, they really won’t work well with Maggie’s. The thing is, Without the auto transformers  the Mac magic is gone and it’s just another solid state amp.  

Autoformers have very wide range of impedances handled at 4 ohm taps.

I have the 1.25kw and also the 462. They will give you all the clarity and dynamics you will ever want plus way more.

I have an mc312 running Sabrinas and chose the 4 ohm taps. I'm sure many other amps sound good too. No regrets or complaints. Happy listening 🎶.

Audiotroy, stop polluting threads.... 

Speakers don't stay at a fixed ohm read the reviews they differ depending on frequency some or the reviews say some speakers dip down to one ohm .so you need an amp that can handle that and not overheat and damage the amp.mcintosh gives that option to match the impedance but it's not good to hook a 8 ohm manufactured amp rating to a 2 ohm speaker load.the reviews are clear on this.thats why different amps match certain speakers.i have read several reviews that suggested playing with the taps at different speakers to find what sounds best.it would be nice to have a brick and motor store that would let you try different combinations and find the one you like.we are all different in the sounds we like.im happy with my mc 1.25 kw but also the michi m8 and parasound halo musical fidelity m8 and even the carver 760 mono sounds good on some speakers.enjoy the music.you can't get around ohms law.

I am 72 and tinnitus has ruined my critical listening capacity, but my first job in HiFi was at a McIntosh dealer. At age 21, my ears were fine, and although I thought I knew a thing or two about audio, I was really just beginning to learn. Our demo system was a C28/MC2105 combo. We demoed from a Pioneer 10” reel to reel playing tracks recorded from a Dual 1229 with an Audio Technica AT15S. Our favorite speakers were ESS AMT-1 Towers. My reading had led me to conclude a Crown DC300 and IC150 should outperform the Mac gear, but listening to each in our sound room proved otherwise. This was all played through 12 gauge zip cord of course…Noel Lee hadn’t happened yet. But those auto formers sure didn’t hurt the sound…

I like more open, unveiled sound.  I've heard MAC many times.  I just can't warm up.  Their amps have plenty of power and are cool looking.  Product loyalty is their big deal.

@daledeee1 Thanks for imposing on us your personal view of why people love their McIntosh gear. It really adds value to the conversation and OP’s original question 

You can call me shat you want but I have McIntosh from the preamp to the speakers. C2700, MC611, XR100 and they sound superb. The only thing not McIntosh is my turntable which is VPI.

I for one have a hard time taking audio advice from anyone who can’t even spell McIntosh correctly in their shouty posts…

That said, call me a fanboy, a dummy, a fool. I don’t care. I love my McIntosh C12000 pre, MC611 monos and MCD12000 transport/DAC. Puts a smile on my face every single time.

@crustycoot +1 on the ESS AMT - 1 towers! My first Real Speakers…

Autoformers are a real advantage in many circumstances. I have never owned a Mac but used the Paul Spetz autoformers for years to match various tube amps to exotic impedance loads (mostly successfully). 

McIntosh solid state amplifiers with autoformers have had a distinct sound to my ears since their inception, in my experience of listening to them at various times since 1972. Warm, not overly detailed, with the earlier versions sounding thin in the highs (eg 2105). I don’t understand efforts denying that such an addition to circuitry has no sound. It’s like denying that differential inputs to an amplifier bring no change in sound, etc.

Simmer. Sorry, your skin hasn’t been toughened up yet. I, like all the MAC fans have an opinion, sorry.  I reread his post to make you happy. Mac fans are very loyal but their equipment is not for everyone. I can’t say the auto former is the problem. Engineers might be able  to explain the benefits or weaknesses. If it sounds good to you, that’s all that matters.  

Speakers are rated in simple Ohm ratings. Most speakers impedance changes across the frequency spectrum. Music signals are a mix of many frequencies at once making for a very complex relationship.

Amplifiers manufacturers give you a simple ohm rating so you do not severely overload the amp. Say by running 2 pairs of 4 ohm speakers in parallel.

Speaker manufacturers give you a simple nominal ohm rating to help you select a suitable amp or which taps (transformer or autoformer) to run their speaker off.

I would agree that a transform will not affect sound staging, etc., however transformers are effectively coils, and coils have an effect on high frequencies. So wouldn't the introduction of a transformer into the chain cause some issue (be it phasing or whatever)in the sound quality in the high frequency range. Just asking.

In this rare instance I actually agree with AudioTroy. The reason Mac amps sound so warm with otherwise neutrally voiced speakers is the autoformers. The same goes for other brands’ transformer-coupled output stages. It’s essentially the complete opposite end of the short-signal path design spectrum. 

I can't imagine any good reason for using an autoformer in modern high quality solid state amplification.

Sorry if this has already been covered but what is McIntosh’s reasoning for using autoformers in their modern equipment? Genuinely curious. Thanks

@som Wrote:

Sorry if this has already been covered but what is McIntosh’s reasoning for using autoformers in their modern equipment? Genuinely curious. Thanks

See here

Mike

Interesting posts, I generally value Audiotroy's experience however regarding Mac no. I stayed away from Mac for 30 years because of their no discount 'snooty' policy. Recently I replaced an amp with similar power into 4 ohms(my speakers claim) and more into 2 with a pair of MC611's. I'm not familiar with 'traditional' mac sound, but I can't imagine anything at or near the price offering the level of bass detail and depth at low and mid volumes. I think at loud volumes the room takes over and is why all amps will sound the same to so many listeners and many amps need to be pushed before they come to life, maybe that's why tube amps are still popular? anyhow if the autoformers are the reason Mac sounds so dynamic at any volume I'm surprised more companies haven't moved to them, seriously. smitten.

I see lots of armchair amp engineers have chimed in. I would love to know about all of your credentials. To think that all of you know more than McIntosh about building amplifiers and using transformers for speaker output. If I were you, I would all send them your resumes, they could fire their engineers and hire you guys since you all know so much about nothing. 

Their “engineers” have been resting on past laurels for decades.

Here in 2024, one can get a $500 “Chi-Fi” preamp like the Topping A90Pro that absolutely smokes the $5500 C49 (yes, I’ve AB’d them!) So Mac would be better off with some new designers. 🤔
 

@helomech 

Yeah, sure, there's always some cheap miracle that is thought by someone to "smoke" older standbys, and they rarely do. Anyway, the "sound" of anything is judged by personal preference.

I have had all ARC and/or Mc’s since about 1980 and feel like I’m familiar with the sound of the two manufacturers. Going through the list:

ARC D 52, VT 100 II, D 70 II . D 52 was dynamic, but smeared the highs with no imaging. Failed and blew up a pair of ProAc Studio 1s.

VT 100. Powerful and dynamic. Very detailed but thinned out the lower midrange to achieve this clarity.

D70 II. Best of the lot. Dynamic and “warm” but preserving great detail. I sold one but just bought another.

Mac MA 230 and MAC 1500, both rebuilt with the preamp section bypassed and acting as a basic amp. Quite dynamic, not slow at all. Punches above its weight. Have the 1500 now.

Mac 2105. A nice sound, powerful but not the last word in detail.

Mac 275 IV, pair in mono. Dynamic, warm, reasonably detailed.

Mac 275 VI. Detailed and powerful, but only after replacing stock tubes with 6550s, Sylvania AT 7’s, and real Telefunken ax 7’s.

Mac 452/462. Powerful, dynamic, quick and detailed. Great amps. Have the 462 now.

Mac MA 6900. Slow and heavy, the only Mac amp I just didn’t like. Now I use the 462 for movies and tv, and the 462 for bass and the D 70 for the mids and highs for music. The best sound I’ve ever had.

Sorry to be long winded, but broad brush assessments don’t tell the story. The sound varies from model to model. The most recent transistor Mac’s are the opposite of the 6900. They are detailed and dynamic, and not especially warm. The 462 is very neutral in its sound.The most recent ARCs reflect the house sound as to dynamics, as to other aspects of the sound I haven’t been able to hear them much.

Hope this helps. 

@degx1000 thank you, this was actually really interesting. Question please. Have you heard the MA12000 unit?  If so, how would you describe the sound?Also, Does that use to modern transistors that you mentioned that are not particularly warm?

dman 

I have not heard that model and frankly, don’t want to be tempted to change again. As an answer to whether autoformers affect the sound, it doesn’t seem to be the case. All the above amps have output transformers. The overall design of the amp seems to have more effect on the sound than the presence of output transformers.

BTW, the design of the autoformers on the 452/462 must be incredible to yield the extremely low distortion figures that the amp has.