How good is the McIntosh MC-2300 vs modern SS amplifiers?

I was hoping someone would compare the fine engineering of this amplifier compared to what Phase Linear, Crown, Quatre and otheres were doing at the time. 

Auto transformers made this design extremely relaible. Ive never been a Mac Man but I have to appreciate good design when I see it. I don't like everything they build and I have worked on much of it. Their preamps have too many buttons in the signal path. But if kept clean they are not a problem.

I just wanted to share my discovery with others who might also appreciate it. In an earlier thread there were posts that called the autotransformer a bandaid for a poor design. It is the essence of this design. Anyone who understands safe operating area of transistors will appreciat this. Most amplifiers that fail are due to engineers who do not. Mac knew.

How an amplifier sounds is subjective and may depend as much as someones mood, their perception of value and cost and build. 

George, I respect your posts here. However you are comparing the Gryphon on Wilsons to the Mac on what speaker? How many years between the comparisons? How many years between the amplifier designs...50 Years!

Do readers here know that almost all modern SS amps are a basic op-amp circuit done over and over again with fancier metal, more capacitors, where are we going with this?

They were probably good in their day, Roger, but so were many others. But you would have them today as your main amp I think not.
A solid state amp that has trouble driving a certain speaker load, can be helped with the use of an autoformer, I say save your money and get the right amp instead.

All you have to do to prove it to yourself, is put a pair of Autoformers on ANY decent solid state amp that can drive hard loads, and hear what it does to the sound compared to when used without them, even on easy loads.

All this fishing Roger, sounds to me like you may be ready to venture into solid state using output transformers?
https://d2gg9evh47fn9z.cloudfront.net/800px_COLOURBOX29710931.jpg

Cheers George

@georgehifi - sorry to say Roger won't be going down that path. He's just a curious guy that does a lot of research. When he heard Curl talk about the 2300's it got the better of his curiosity, especially given their use by the Grateful Dead with the Wall of Sound set up. So he looked into it and thought he would write about some of his thoughts and findings. If Roger was going down the path of building solid state amps, and he has built at least one I know of in the past, I'd be one of the first to hear about it.

I built many solid state amps in my youth, not knowing of the AutoTransformer Macs. But then I was just a child. I did however get a firm understanding of how transistors fail and the circuits necessary for them to be protected against shorts and reactive loads. I learned about safe operating area (SOA). I saw that at the voltages required just to make a 100 watt amplifier would intrude into the SOA of all power transisitors and still does. So the designer has to protect the transistors. I found most of the protection schemes would cause premature clipping into reactive and low impedance loads. 

When an amplifier sounds very bad on a particular speaker and good on others I contend it is misbehaving into that load. Two common examples are current limiting (load line limiting) and outright instabilitiy usually in the form of birdies (small HF oscillations on the wave that look like a bird on a wire). Birdies sound like the worst kind of clipping, yet the amp may be far from clipping. 

This concept of matching speaker and SS amplifier appears to be misunderstood and a bit overrated. As stated above the particular speaker may make the amplifier unhappy. If the amplifier is happy then one may consider impedance variations that are exaserbated by high output impedance. 

If I were to make SS amps I would like likely use autoformers because:
  
1. I know how to make them
2. They allow me to use the full rating of the transistors.
3. They allow me to use same sex transistors
4. They protect against DC faults
5. They present the optimum load to the amplifier via their taps

If I were to make SS amps I would like likely use autoformers because:

Judging by this statement, as I know your no fool, and that you have never A/B’d a highly rated solid state amp that’s happy driving into a speaker considered to be a hard load, then place the "said" best autoformers in to see what they do. You will be surprised at just how much the sound degrades.

Granted autoformers have their place with amps that cannot drive certain loads, but I say save the money and get the right amp instead, you’ll be far better off.

If you have an OTL amplifier you should know that the power is greatly reduced into low impedance loads. Even worse is that low impedance loads will overheat the tubes at high power levels as most of the power supply voltage is being dropped across the tube not the load. So low impedance loads are hard on the tubes and cause higher distortortion All of these ills can be solved by the use of a proper Autoformer.

OTL’s are the best sounding tube amps there are ( even maybe solid state also) if they are used withing their comfort zone driving speakers that have easy loads they like, as with the highly rated solid state amp above, that changes very much so once you introduce an autoformer, into the same system, I doubt that Ralph would use autoformers if there was no need to.

It all comes back to the right amp for the right job, if not an autoformer can be a "band-aid" or "interim" fix, but an expensive one.

Cheers George