McIntosh Unity Gain with SolidState???

[Circlomanen]

Anyone built an SS version of McIntosh unity gain transformer coupled output stage?
I think its a brilliant solution and Im thinking of winding a transformer to try it.
Any thoughts, ideas or experience is appreciated!

[GRollins]

The tube McIntosh designs used a unique output transformer that had extra taps on it for feedback to earlier stages. Their solid state designs don't use transformers in the usual sense; they're autoformers. To the best of my knowledge, no other company uses such a thing at this time.
Can an autoformer be done on a DIY basis. Absolutely. And that's pretty much the only way it'll happen. I'm not aware of any transformer manufacturer that offers such a thing in their standard product line. McIntosh used to (and I believe they still do) build their own.

Grey

[john curl]

I don't think that a solid state version would be useful. You must try to understand why the unity coupled circuit was invented in the first place.

[SY]

GR, if I'm not mistaken, Atmasphere offers an autotransformer as an accessory. And as John intimated, notch distortion is not an issue.

[GRollins]

Now that you mention it, I think I remember seeing something about that. I bet they roll their own, too.

Grey

[Circlomanen]

Thanks for answer!
Im not intrested in the autotransformer, but in their original pentode with unitygain coupling and crosscoupled screengrids. When thinking about it it seems to work as a cascoded cathodefollower. The Cathode-Screengrid voltage being constant, and 100 % local feedback.

Im just fooling around trying to learn all about balanced circuits. I found this one very intresting, and I think its a worthwhile expirment translating it to solidstate.

Johannes

[Tony]

for tubes it makes a lot of sense, but for solid state, what for? speaker impedance levels are within reach of solid state state circuitry anyway...

[Circlomanen]

The exact same reason im building amps in the first place: Its fun!
I know there is no real good reason to experiment with all kinds of strange circuits. Its better and much simpler buying a Krell or PassLabs X-350.
I like transformers in the output section of amps. They make the amps safe and easy to build. Dc offset is no big problem.No loudspeaker protection needed and they seem to sound very good. Se Susan Parkers Zeus!
I like the concept of connecting both source and drain to the output transformer, even though i cant realy explain why. Maybe its just cool.
However its a fun expirement and im rewinding a transformer at the moment to try it out.
Anyone having any thoughts or ideas are very welcome to tell me about them.
Most of this is unknown to me so Im in desperate need of information about the circuits and possible variations, pros and cons and so forth.

Johannes with fever and a bad cough.

[Tony]

The exact same reason im building amps in the first place: Its fun!

a valid reason i aggree, not that i need to. diy is all about fun!
btw, i made a desgn for output traffo for the tube mc270 amp for a friend but he insists to =see the original data, can you help? thanks

[Circlomanen]

The info I have is in Ir.Menno van der Veens book, Modern highend valve amplifiers.
A very nice book by the way.

What does "btw" mean?
Johannes.