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Rosinante 16th November 2010 02:28 PM

McIntosh Goodness From Scratch
Has anybody built something like a McIntosh MC-275 from scratch? Why not?

danFrank 16th November 2010 02:41 PM

Here we go again! A MAC is no big deal to build from scratch, IF you have a source for their rather unique output transformers. I know of nobody except for Plitron that makes any type of output transformer that even closely resembles the old McIntosh "unity coupled" output transformers. And Plitron only has one transformer in their inventory that is like the old MAC units. It would be better suited for making a MC-40 /MC-240 clone, not a MC-75 / MC-275 IIRC.
Do a search on this forum for "McIntosh Output Transformer" or "Unity Coupled Transformer". This has been written about here a lot in the past.

Rosinante 16th November 2010 02:45 PM

Thanks, Frank. I am not shy about doing my homework (Search), but without the information you provided, it would have taken me a while to discover that the output transformer is the rarity. Again, thanks.

danFrank 16th November 2010 02:47 PM

And one more thing... If you decide to do this project, make a MC-40 clone instead. They are good for an actual 60 watts RMS (McIntosh are severely under-rated in their specs) and are probably the best sounding of all the old common MAC tube amps (MC-30, MC-40, MC-60, MC-75).
You can occasionally find old MAC outputs on Ebay, from NOS to old rusty bad units. Good ones go for $200-$350 each depending on what model.

20to20 16th November 2010 02:59 PM

Glad to hear the hum is solved.


Originally Posted by Rosinante (
Has anybody built something like a McIntosh MC-275 from scratch? Why not?

This question could surely start in interesting discussion on the philosophy of cloning a classic.

When do you stop calling a clone that is not an exact duplicate with original parts by its given model name? Is it a Mac 275 if the power tranny is not the original? Will it ''sound'' the same? Does the builder care, if it sounds the same? A different OPT set? Not the same brand of coupling caps? Not the same driver tubes? Not the same finals? Not the same chassis?

When does an '69 Impala stop being an Impala? You like the body but you think a Ford power train is ''better.'' So you slap in a new motor/tranny/differential Bigger wheels and lower the roof but you still call it a '69 Impala. It won't ''sound'' the same.

Have fun with that game. Everyone has to play it. The winner is normally disputed.

M Gregg 16th November 2010 03:07 PM


Originally Posted by Rosinante (
Has anybody built something like a McIntosh MC-275 from scratch? Why not?


I wonder if anyone thought of a kit for MC 40 or 275! original shape chassis!

M. Gregg

Rosinante 16th November 2010 03:07 PM

Well, it looks like this sort of project is WAY, WAY beyond my capabilities. My next project will be my first, and I barely understand volts, amps and watts.

But you know.....I am just ignorant enough to question all this scary talk about "don't try this at home." Let's take an example I am vaguely familiar with regarding automobiles. In the late fifties Porsche made a 2-liter, four-cylinder, four-cam (sixteen valve) engine the size of a suitcase that could spin 8000 rpm and make 200 hp. Amazing. They say it takes an expert about eight hours to adjust the valve lash. This is because the cams are not driven by belts or chains, but rather are gear-driven. So.....adjusting them is an interative process of measuring - adjusting - measuring - adjusting - measuring - adjusting......and more measuring and adjusting. The point is that potentially, virtually anyone with basic mechanical skills and a few specific tools could do it, as long as they study and understand the steps.

Again, I am ignorant of electronics stuff. Not dismissive, just ignorant. I just don't understand why an expert could not make a parts list and lay out a build procedure, including whatever testing and adjusting must be performed, that could be followed by anyone with access to the proper tools and equipment.

kstagger 16th November 2010 03:07 PM

no offense to the Mac-heads, but there are other amps I would rather build first!

M Gregg 16th November 2010 03:19 PM

Where can you buy a "Mackit" replica "look alike"
That sounds good?

I always think it would be nice to be able to buy KIT amps like KIT cars.

Rosinante 16th November 2010 03:23 PM

FWIW, I don't care one whit about originality for originality's sake. My goal is the sound. I have heard early McIntosh tube stuff, and the sound is jaw-dropping. That is my goal. The jaw drop.

I'll use the car analogy presented by 20to20, but with a different make and model. I own a 1978 Porsche 911SC coupe. It is a lovely car in a very dark, dark, dark opaque (non-metallic) chocolate brown. It has lovely curves, not unlike a woman. But you know.....I don't care what it looks like. I kinda wish it looked like a Yugo. I don't revel in the stares I get while driving it. This is not a piece of jewelry. It is a CAR. My sole interest in this car is performance-related. It is like a go-cart coupe with license plates. I have it down to just under 2400 lbs now, with solid suspension bushings, blah blah blah. In a word, this car is the most "obedient" I have ever driven. Stops on a dime, corners like it's on rails, etc. She's a dancer.

This is what I am going toward in this, my latest obsession. Tube sound. I am in the construction industry, and if I can draw a chassis, I can get it fabbed from stainless for almost nothing. Chassis is not a problem. So......if I had one of these specially-wound Philtron (or NOS McIntosh) transformers (or two or three or whatever.....), could I work with an electronics shop to assemble what is essentially a McIntosh MC-240? Is there a special magic potion or incantation, or perhaps some antimatter or fairy dust that is necessary to the process?

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