Signal tube versus power tube, sound impact?

Lot's of good suggestions here, although overall maybe a bit confusing/overwhelming (no surprise).

Personally I've had good outcomes with the front (small) then back (power) strategy, other than one KT150 based amp as there are no other options besides Tung-Sol. In this case replacing the stock JJ pre-amp tubes with some NOS Telefunken Diamond Mark Red Tips worked magic. 

I have not been impressed with GL KT88 tubes vs. JJ. I returned the GLs. This was in my first tube integrated - a LineMagnetic.

A trusted source is important and I have mostly used Brent Jesse at audiotubes.com. Everything he has is listed on his website, and he gives good advice without being pushy or overselling, and has a very reasonable return policy.  

Although expensive, if you want to warm things up, the NOS Mullards are pretty special and currently in my tube DAC - however, and this is where Brent Jesse comes in - I have some 1950's GE long plates (branded as Wurlitzer) that I rotate in and out of the DAC that sound remarkably good in the DAC at 1/4 the price.

I think mcIntosh is JJ tubes for stock. These tend to be generally cheaper and may be more reliable which may be why they use them.

I guess if they put in better tubes they see a lot of problems with people complaining about malfunctioning tubes when they buy the new amplifie…

So here is a case where durability and reliability may impact quality. So you maybe better off replacing these JJ tubes for something that may be better?

Sort of like the power cords which are kind of crappy that they supply with their amplifiers and they know the consumer will probably replace the cords.

@macg19

Audiotubes.com

He’s got a very interesting website with lots of commentary. Further his prices are incredibly expensive. Return policy is alluring but from a practical standpoint I doubt many even returning tubes because of the difficulties involved.

But it’s a pretty damn good website

Expensive? Maybe, but I’m some cases how would you compare as he likely has inventory that no one else has?

I have returned (exchanged) 1 set with no issues.

The way I look at it is value for money: good advice, no concerns about fakes or items not as described etc.

having said all that there are several other very reputable dealers out there. Good luck and have fun!