I've done a lot of tube rolling in my time on various preamps and amps and as I said before, it does have an effect on the sound, sometimes tightening the bass a bit, opening up the midrange slightly, or sweetening the highs a tad, but the effects are subtle at best. What I have never heard, was a total change of "character" of a given device. A case in point were the Jadis preamps, which had an euphonic sweetening of the midrange, not unlike certain Koetsu cartridges, which could be seductively beautiful sometimes, but certainly were a colouration away from neutrality. We've tried our best - at a time when good tubes were more plentiful and less expensive - to get rid of that sound ... and failed. Another case in point, this time with Jadis amps, were the KT90, where you could trade more slam with a tiny loss of midrange solution, that was audible, but certainly did not change the general voicing, or character of the amp. (Jadis Defy)
Besides, there are myriads of amps these days, which use identical tubing , but certainly sound very, very different. So basically, in my opinion, it is the design and quality of parts which count. The choice of tubes play a part, especially their lack of tube noise, also the choice of tubes within a given design, using the tubes capabilities vis a vis the rest of the design. Sometimes an amp is built around a certain tube, like the Zanden 9600, which is built around two 845s. But the idea that all 845 amps would sound like a Zanden is simply so far from reality as the idea that I could change the sound of this amp with swapping 845s
around. I've tried it, and it is just not so.
Again, and maybe I'm wrong, to my reasoning, only if an amp's design is absolutely neutral, just like the proverbial "straight wire" and where the "gain" were just delivered by the tubes and nothing else, the argument would hold true, that it is the tube which makes for the sound of the device. I'm not an expert, just a long time user, but I doubt if a component like that exists. Rather I would submit, that it is the total design, be it tube, transistor or hybrid, which makes for neutrality of an amp or a deviation from it.
Besides, there are myriads of amps these days, which use identical tubing , but certainly sound very, very different. So basically, in my opinion, it is the design and quality of parts which count. The choice of tubes play a part, especially their lack of tube noise, also the choice of tubes within a given design, using the tubes capabilities vis a vis the rest of the design. Sometimes an amp is built around a certain tube, like the Zanden 9600, which is built around two 845s. But the idea that all 845 amps would sound like a Zanden is simply so far from reality as the idea that I could change the sound of this amp with swapping 845s
around. I've tried it, and it is just not so.
Again, and maybe I'm wrong, to my reasoning, only if an amp's design is absolutely neutral, just like the proverbial "straight wire" and where the "gain" were just delivered by the tubes and nothing else, the argument would hold true, that it is the tube which makes for the sound of the device. I'm not an expert, just a long time user, but I doubt if a component like that exists. Rather I would submit, that it is the total design, be it tube, transistor or hybrid, which makes for neutrality of an amp or a deviation from it.