Good idea to swap McIntosh amp stock tubes?

BS.  Half the fun of owning a tube amp (or preamp) is trying new (equivalent) tubes.  Not always better, but often different and worth the effort.

I don’t own a Mac amp, but I’ve really enjoyed tube rolling and dialing in the sound just the way I like it.  There should be no reason you can’t do the same.  You can always add the stock tubes back in the mix.  

Tube amplifiers that reflect sound changes when tube swapping occurs may not be designed very well.

A bit of an obnoxious assertion / wording on MC's part. It's true that if a circuit design runs its tubes in an egregious way (e.g. way out of spec, or far from optimal conditions for a given tube type), then tube rolling can have much more sonic impact than normal. But I've always found that tube rolling has audible effect, even in well-engineered components and for slots that have been advertised to "not" reveal tube rolling differences (e.g. cathode followers, grounded grid outputs with SS CCS).

I think one of the most frustrating things about this situation is that McIntosh installs tubes that are questionable as to how good they are.  I believe the consensus is they are not as good as they probably should be. They put their fancy logo on each of the tubes and somehow that’s supposed to make them perform better.

Does anyone believe the tubes used by McIntosh are good? And then they have a problem if we try to change the tubes because they have designed their amplifiers based upon tubes that may not be as good as they should be so they advise against changing out these tubes.

This is very annoying and really shouldn’t be. I have no idea how to evaluate the quality of their tubes except from other people are saying and many many people are saying they improve upon the McIntosh amplifier when they swap out the tubes and the people saying this are fairly seasoned in their abilities when evaluating an amplifier after all their customers of McIntosh - people who know how to evaluate sound quality I would hope or better at it than most. So clearly respectable views and yet the tube quality installed in the amplifiers is still less than what people feel comfortable with.

I think one of the most frustrating things about this situation is that McIntosh installs tubes that are questionable as to how good they are.  I believe the consensus is they are not as good as they probably should be. They put their fancy logo on each of the tubes and somehow that’s supposed to make them perform better.

Does anyone believe the tubes used by McIntosh are good? And then they have a problem if we try to change the tubes because they have designed their amplifiers based upon tubes that may not be as good as they should be so they advise against changing out these tubes.

If they’re JJ-sourced, then they are not good. JJs go right in the trash. Chinese tubes can be extremely bad or very good (and everywhere in between), depending on source & screening. Russian tubes are generally good to very good.

When you have very selective large tube suppliers / buyers like Upscale Audio and VAC - who completely avoid JJ tubes - that says a lot. The only reason many use JJs is price and availability.

And there are definite reasons why a brand would want to discourage tube rolling "experiments".