autoformer

[steve59]

After switching to the MC611,s my KEF Blades really opened up at low volumes, seriously! I went to the shop to buy a small pair of 2 way, persona b speakers to use for low volume late night listening because the big full range speakers sucked at low volume. At 70 db the blades had no snap, no dynamics or anything that brought attention to the music. I decided to try new amps instead. Out went the Hegel H590 and in came the MC611's and I was instantly startled! #ven cold fresh out of the box the amps, at less than half a watt were giving up layers of bass detail and layers of soundstage depth, detail and tone I never got at low volume before. Does the autoformer act like a loudness button? is this feature the reason tube amps sound so good compared to SS? I have to say I couldn't have imagined this much improvement from a power amp working at idle, 1/100th of its rated output.
Can anyone explain what's happening?

 

[dinov]

Sounds like the McIntosh better matches your preamp in terms of sensitivity. Nothing against Hegel but I am a McIntosh fan, and their autoformers do make a difference in sound. Regardless, enjoy the improvement in synergy in your system.

 

[A-Line]

Neither of my McIntosh amplifiers have autoformers. McIntosh claims that there's no difference in sound while using their amplifiers with or without autoformers.

Autoformers add additional cost and weight to McIntosh amps/integrated amps that use autoformers.

My casual observations regarding those that use McIntosh amplifiers is that they often mismatch speakers to amps. One such instance is the myth that using 2 MC275 tube amps in mono mode vs 1 in stereo mode sounds better. Same thing for using 2 MC2102 tube amps vs 1 MC2102 in stereo mode. Closer examination reveals a mismatch of speakers to those tube amps.
McIntosh tube amps don't use autoformers but most of their solid state amps do.

I've heard subtle differences between their solid state amps using autoformers vs the ones without. A individual interested in the McIntosh brand will have to make a choice which is right for them. Again careful speaker selection is necessary.

Most, if not all, issues regarding McIntosh amplifiers and speaker selection can be immediately resolved by careful audition at the audio shop.

Just my opinions.

 

[dinov]

Neither of my McIntosh amplifiers have autoformers. McIntosh claims that there's no difference in sound while using their amplifiers with or without autoformers.

Autoformers add additional cost and weight to McIntosh amps/integrated amps that use autoformers.

My casual observations regarding those that use McIntosh amplifiers is that they often mismatch speakers to amps. One such instance is the myth that using 2 MC275 tube amps in mono mode vs 1 in stereo mode sounds better. Same thing for using 2 MC2102 tube amps vs 1 MC2102 in stereo mode. Closer examination reveals a mismatch of speakers to those tube amps.
McIntosh tube amps don't use autoformers but most of their solid state amps do.

I've heard subtle differences between their solid state amps using autoformers vs the ones without. A individual interested in the McIntosh brand will have to make a choice which is right for them. Again careful speaker selection is necessary.

Most, if not all, issues regarding McIntosh amplifiers and speaker selection can be immediately resolved by careful audition at the audio shop.

Just my opinions.

I’m not sure I understand your logic. McIntosh autoformer amps have different taps for different ohm rated speakers ie, a 4 ohm tap and an 8 ohm tap for correct speaker matching and maintaining consistent wattage output. This is true even in their vintage tubed gear so I’m not sure about how amps can be mismatched to speakers, unless it’s just preference.

 

[Charles S]

Almost all well thought of and more expensive more powerful McIntosh power amplifiers use autoformers. This is because McIntosh believes that autoformers are integral to the design of their power amplifiers and integral to the design of a properly engineered power amplifier. McIntosh currently has on the market the MC830 which is a direct coupled amp and a MI502 which is a Class D 2-channel amp, both of which are offered as alternatives to their mainline autoformer amps.

It's not well known that McIntosh has done extensive research into all types of Class D amplifiers and uses SMPS power supplies in all their current CD players to drive their transports. McIntosh has been using SMPS's since the early 1980's in various applications but feels that they are inferior to the more conventional toroidal power supply at present time. Most likely, I think that you will see more and more manufacturers use some form of Class D including McIntosh, who has the superior technology and advantage because of their extensive research in these amplifiers.

According to McIntosh a bridged MC275 will sound better than a 2-channel MC275 mainly because it is more powerful. The incorrect information that has been circulating is that the bridged MC275 sounds inferior to a single MC275. The advantage of the bridged MC2102 or the MC275 is twice the power, which is very important especially if you like your music loud or have low sensitivity speakers. I think the MC1502 is an especially fine 2-channel tube power amp and definitely superior to two bridged MC275's or MC2102's.

 

[A-Line]

I’m not sure I understand your logic. McIntosh autoformer amps have different taps for different ohm rated speakers ie, a 4 ohm tap and an 8 ohm tap for correct speaker matching and maintaining consistent wattage output. This is true even in their vintage tubed gear so I’m not sure about how amps can be mismatched to speakers, unless it’s just preference.

Mismatched speakers in that the amplifier is not powerful enough to power the speakers at their full potential. Using my Spendor S8e's in 2007 I heard no difference in sound regarding a single 2102 vs bridged mono 2102, same for 275 vs bridged 275.

If people can hear a improvement using a bridged 2102 or a bridge 275 vs just a single stereo amp then a additional purchase maybe justified based upon that improvement. However, I never heard such a improvement.

By the way, the 275 doesn't have much bass response, with or without being bridged or even daisy chained. It's just the way it is designed.
The 2102 does have good bass response and was advertised as such back when it was a current production amplifier.

Here's a glossy mag review of Spendor S8e speakers: https://www.theabsolutesound.com/articles/spendor-s8e-loudspeakers-1/

I personally don't regard what those mags say about products as being accurate because every review that they do is always a positive review...

 

[A-Line]

Almost all well thought of and more expensive more powerful McIntosh power amplifiers use autoformers. This is because McIntosh believes that autoformers are integral to the design of their power amplifiers and integral to the design of a properly engineered power amplifier. McIntosh currently has on the market the MC830 which is a direct coupled amp and a MI502 which is a Class D 2-channel amp, both of which are offered as alternatives to their mainline autoformer amps.

It's not well known that McIntosh has done extensive research into all types of Class D amplifiers and uses SMPS power supplies in all their current CD players to drive their transports. McIntosh has been using SMPS's since the early 1980's in various applications but feels that they are inferior to the more conventional toroidal power supply at present time. Most likely, I think that you will see more and more manufacturers use some form of Class D including McIntosh, who has the superior technology and advantage because of their extensive research in these amplifiers.

According to McIntosh a bridged MC275 will sound better than a 2-channel MC275 mainly because it is more powerful. The incorrect information that has been circulating is that the bridged MC275 sounds inferior to a single MC275. The advantage of the bridged MC2102 or the MC275 is twice the power, which is very important especially if you like your music loud or have low sensitivity speakers. I think the MC1502 is an especially fine 2-channel tube power amp and definitely superior to two bridged MC275's or MC2102's.

My dad had a MC275, C22, MR67, and Klipsch Cornwall speakers. He also had a Garrard 301 turntable.

So I grew up with that sound until I left home and went on to college. The sound of the 275 has not really changed sound wise over the decades, at least to me.

Some have reported that the MC75(which are mono's) sound better than a bridged mono 275.
I've never listened to a pair of MC75's.

I've never had a interest in high power amplifiers or huge speakers but I did like the McIntosh sound. I finally purchased my first McIntosh piece in 2006, the MC2102. Now I have several McIntosh pieces.
Prior to that I had ReVox electronics with a LP12 and Linn Sara speakers. I still have my ReVox receiver & tape deck. My ReVox receiver has a excellent tuner section and I play my tapes through it as well.

Everyone hears a bit different so find the sound that's right for you and go with it.

Just my opinions.

 

[DeYoung]

Mismatched speakers in that the amplifier is not powerful enough to power the speakers at their full potential. Using my Spendor S8e's in 2007 I heard no difference in sound regarding a single 2102 vs bridged mono 2102, same for 275 vs bridged 275.

If people can hear a improvement using a bridged 2102 or a bridge 275 vs just a single stereo amp then a additional purchase maybe justified based upon that improvement. However, I never heard such a improvement.

By the way, the 275 doesn't have much bass response, with or without being bridged or even daisy chained. It's just the way it is designed.
The 2102 does have good bass response and was advertised as such back when it was a current production amplifier.

Here's a glossy mag review of Spendor S8e speakers: https://www.theabsolutesound.com/articles/spendor-s8e-loudspeakers-1/

I personally don't regard what those mags say about products as being accurate because every review that they do is always a positive review...

Is it safe to assume that you regard any McIntosh review done by The Absolute Sound as not being “accurate “ simply because it might have a positive outcome ...like this review of the MC 462?
https://theabsolutesound.podbean.com/e/mcintosh-462-stereo-power-amplifier-review/

 

[A-Line]

Is it safe to assume that you regard any McIntosh review done by The Absolute Sound as not being “accurate “ simply because it might have a positive outcome ...like this review of the MC 462?
https://theabsolutesound.podbean.com/e/mcintosh-462-stereo-power-amplifier-review/

I don't regard any glossy mag/online reviewer as being accurate in terms of sound.

Audition of components is always advised.

 

[DeYoung]

The fact is autoformer equipped amps have a way of reproduction that is "of a different quality"... not "better quality" than non -autoformer amps.
That's McIntosh's way of saying there's no "difference"