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

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

Can we agree that good amplifiers drive a large number of speakers very well and changing to another "good" amplifier will drive the chosen speaker just as well? These amplifiers have certain common characteristics that make them sound very similar on a wide variety of speakers. 

Can we further agree that some amplifiers have (rather undesirable) measurable characteristics that will make a given speaker sound uniquely different on this amplifier. And though we might like the coloration this combintion produces, it is not what the speaker designer had in mind? 

If the right amp has to be found for just some one speaker, I would say that is a bad amplifier waiting to find a home. How is one to find this perfect match?  How many of these colored amplifiers would one have to audition? Take the current OTL amps which all have high output impedance. They can properly drive less that 10 % of the speakers out there. How about an OTL that can drive a wide variety of speakers properly?

If the right amp has to be found for just some one speaker, I would say that is a bad amplifier waiting to find a home.

So what your saying is an amp that can drive the Wilson Alexia’s known impedance of down to 0.9ohm is a bad amp?????

No you’ve got that arse about face, the speaker is the problem being too hard to drive and the amp that can do it is a great amp, and will not only drive it but anything else as well. Definitely not  a bad amplifier waiting to find a home.

Cheers George

How about an OTL that can drive a wide variety of speakers properly?

No such thing, unless you stick an autoformer band-aid on it for the hard to drive ones. Then you ruined the whole advantage of the OTL design and what it can do.
Your better off getting one of your amps to do the job if you wish to stick with tubes, or putting a proper output transformer on the OTL, again a backward step to what an unhindered OTL is capable of giving with the right speaker.

Cheers George

How about an OTL that can drive a wide variety of speakers properly?


No such thing, unless you stick an autoformer band-aid on it for the hard to drive ones. Then you ruined the whole advantage of the OTL design and what it can do.
Your better off getting one of your amps to do the job if you wish to stick with tubes, or putting a proper output transformer on the OTL, again a backward step to what an unhindered OTL is capable of giving with the right speaker.

Here is an interesting story that happend to me. Jim Jordan, the designer of Vaughn speakers fell in love with the Wavelength 300B Cardinal with silver transformers and all. Big bucks for a 7 watt amplifier. This amplifier has rather low damping, but within its power range I assume it to be a good amplifier. He named his speaker after the amplifier. In this case the amplifier came first and he designed a speaker he felt worthy of it as other speakers he tried were not.

https://www.vaughnloudspeakers.com/story

Then he met me, actually I went to his house to hear his speakers. I took along a rough prototype of my OTL for him to hear. Somehow he convinced me to make one for him and one for his customer in stereo on a nice chassis. Now he uses my AUTOFORMER OTL all the time. It has very low distortion very low output impedance. It is of the Futterman School which always has low output impedance. Mine only two output tubes, triode connected, and one driver tube per channel. Most OTLs have 6-12 output tubes per channel. Lots of heat, lots of matching.

The autoformer has no special materials, I make them of standard copper magnet wire and M6 Iron. It is very small, costing a fraction of a silver 300B transformer. It is partially in the feedback loop or not, as desired. Id does effect the sound and Jim moves it from time to time for different listening. He likes the subtle changes it makes.

I wound 4, 8, 16 ohm taps and 32 ohms is direct output. At 32 ohms the amplifier puts out 30 watts into a 32 ohm load. An 8 ohm load connected to the 32 ohm tap produces 3 watts because the tubes can only provide that much current (about 1 amp). But any load connected to its proper tap will put out 30 watts. To my suprise the Autoformer extends the high frequency frsponse from 120 KHZ direct to 160 Khz using the 8 ohm autoformer tap into an 8 ohm load, or 4 into 4, etc. All the taps produce the same results into their specified load.

I arrange a feedback wire on a lug and tell the user to move the feedback wire to whichever tap they are using so the feedback is always on the tap looking right at the speaker. Sometimes the put it on a different tap and like that better. Its all good, the amp is stable and happy.

In closing the SA-6 I deisgned for Counterpoint and the large Futtermans will drive a wide variety of speakers with 100 watts per channel with very low distortion and high damping. Keep in mind that the Circlotron amplifiers are an entierly different animal. They do not have low output impedance of a lot of current. All OTLs are not the same

I invite George and others to take a little time and learn about the Futterman style amplifiers and then say something. Little by little I will get around to all of it, but it took me years to fully appreciate his work, the man was very smart and I am happy I got to spend an afternoon in his shop.