Good idea to swap McIntosh amp stock tubes?

@emergingsoul 

Tubes last a long time in Mcintosh Tube amps and preamps.  Well matched great quality tubes will give you the best sound. 

I use two MC275s amps in monoblock mode and a McIntosh C2300 tube preamp  I put away the McIntosh tubes as spares a long time ago - 2013.  For the preamp, I use Telefunken smooth plate 12ax7 vintage tubes bought on ebay.  They sound great in the line stage and MC phone stage.  In the amps, for the power tubes, I prefer - New Matched Octet (8) Genalex Gold Lion KT88 Reissue Vacuum Tubes (note: VIVA tubes usually has a good price),  and learned on this forum -   the frame grid JJ E83CC - 12AX7 (tube depot carries them).  For 12AT7, pick your poison, but, I use NOS MATCH QUAD *D* GETTERS 5 STAR 6201 ECC81 12AT7 3 MICA TUBES USA MADE 1950’S (ebay has cheap prices on these).   All of the tubes I mention are still relatively inexpensive and perform extremely well in my Mcintosh amps.  Yes, the small tubes will wear out before the big power tubes.  12AT7 first, then, 12AX7, then, the KT88 power tubes.  In the Mc275s, this is the order of highest to lowest wear over time.   Note: You can see my stereo rig in my signature,. 

Note:  Regarding sound influence from most to least, my opinion is the Pre-amp Tubes first - 12ax7, Amp small tubes 12ax7 second, Amp small tubes 12at7 third, and the Power Tubes KT88 last. 

My experience differs from hjdca.  In my MC2000 the original tubes lasted 10 years before one of the power tubes went.  At that time I replaced the complete tube set.  I bought Gold Lions for the power tube replacements, and my tube guru chose replacements for me for the small tubes.  After 7 years one of the Gold Lions went and I bought another set of the same.  I use the amp less frequently these days and haven't had any issues since.  But my experience and belief is that the power tubes do not last as long as the small tubes.  By quite a bit, actually.

Bill

What you need to take into account is that most top end manufacturers using tubes burn their tubes in and then test them thoroughly to select the parameters that are optimal in the intended place in the circuit.

So for example, they may use the same tube in their preamp and power amp, but you will find that they have selected tubes with specific performance parameters for phono or line etc, even down to what type of circuit the tube is used in.

In other words, quality manufacturers will buy in the tubes, run a burn in and selection process and then sell off what is outside the parameters required to tube resellers.

When you buy the same tubes from a reseller, chances are despite being carefully matched, it has probably already been rejected by a manufacturer, not because it is poor, but because certain parameters are outside the requirements they are looking for.

When you buy expensive NOS tubes, they can be an improvement, but the downsides are that if they are not optimum you might well find they are noisy ( most modern tube gear run tubes very hard to get linearity ) or not last - and if 1 goes you have to find another pair. If I use NOS I go for a matched quad for a single pair of tubes.

@facten + 1

Tubes changing the sound of an amp has nothing to do with how well the amp is designed. It's just a fact. If an amp uses 300B tubes for example, and it sounds the same whether you're using $400/pair Gold Lions or $1400/pair Western Electric, I would suggest that there is a problem with that amp's design. 

Is anyone experiencing very sensitive red lighting when it comes to McIntosh amplifiers? I’ve experienced red light blinking and constant red light conditions and both times I replaced all the small tubes and this solved the problem.

I’m told if I use NOS tubes and because of their age they may be unpredictable and cause problems with the very sensitive circuitry of McIntosh amplifiers. I’m not sure Mac supports using these for fear they would damage the unit but they really don’t explain why that is.

I am kind of concerned that the quality of stock tubes used by McIntosh which are JJ I guess.  they may not be of good quality, I've never heard anybody say anything good about them,  and maybe I could be doing better.  Having all these red light conditions occur I don’t think is healthy for the circuit boards. I bought McIntosh amplifiers so I could avoid these problems.