Well...here is my take:
1. I find tube rolling has a surprisingly small effect on sound. I have a GEC 6AS7G brown base. In fact, I have two of them. Do I think they sound significantly different or better than the other 6AS7Gs, 6080s, 5998s, etc. that I've tried? Not really. They happen to be among the quietest tubes I've used, but I think that is just luck of the draw and specific to these particular tubes, not something that is inherent in the GEC design. I would expect there to be numerous "cheap" tubes that are just as quiet, if you can find the right one. And you can probably find any number of GEC 6AS7Gs that are very noisy. My basic position is this: I wouldn't bother "upgrading" the tubes in the Crack. Frankly, every tube I've tried has sounded excellent, and differences between tubes have been small to non-existent.
2. The drive to upgrade tubes and caps primarily stems from one source: insecurity. Something else might be better, and I'm worried that I don't have the best, so I might as well spend a bunch of money to be on the safe side. Feel free to disagree if you want, but I know that is how it works with me. It isn't that I feel a need to show off (my wife and daughters have zero interest in this stuff), it's just that I want to listen to the best possible sound. In the absence of first-hand knowledge about what sounds best, it is easiest to just spend money. That doesn't necessarily mean that what I wind up with ACTUALLY sounds the best, but it calms my anxiety. [Look, I'm wierd, OK? At least I know this about myself.]
3. I'm not yet convinced that upgrading the caps to film caps makes a huge difference, or that there are enormous differences between film caps. There may be, but the challenges in trying to rigorously test and identify those differences strike me as insurmountable. Caps may make a bigger difference in speaker crossovers, and maybe that is why we expect them to make a big difference, but I don't know if they actually do. Yet I still "upgrade" caps because I am a small, insecure and weak man.
4. This is a hobby. If upgrading caps or tubes or whatever floats your boat, then go for it. Notwithstanding my weak-willed ways, I don't see how silver wire is or could possible be better than copper wire, given that copper wire is usually thicker than silver wire, therefore more than compensating for the small advantage in silver's conductivity. But, if people want to blow money on silver wire, that's no skin off my back. I find installing film caps, and trying to figure out how to fit them, is kind of fun, so I do it.
5. It is virtually impossible to make an informed decision on how to change your system's sound. Suppose you find that your Crack is lacking in bass, or that the treble is a bit hot. Or the dynamics are lacking...whatever it is that you want to improve upon. Now, how will you go about figuring out which tube or cap to install? Pick any tube or cap, and to the extent that you can find any reviews at all, they will be reviews in someone else's system, using different components. Reviewer A will tell you that tube X has great bass punch. Reviewer B will tell you that the bass punch of tube X is sorely lacking when compared to tube Y. But Reviewer A has a separate review where he says tube Y has the worst bass he's ever heard. So, will tube X give you more or less bass? The same thing applies to caps. Reviews are all over the place, highly subjective, and basicaly worth a hill of beans. So you wind up buying something random, sticking it in, and seeing if your system still makes music that is vaguely acceptable.
6. If you want to make an immediate, obvious, objective and significant change to the sound of your system, then buy new headphones. I like to say that on a 10 point scale, the magnitude of the change in sound is 9 if changing your headphones, it is generally 2 when switching between amps using the same basic technology (e.g. among solid state amps, WOT tube amps, or OTL tube amps), it is maybe a 4 when switching between amps using different technology (e.g. switching between a solid state amp and an OTL amp), maybe a 1 when changing caps or tubes, and, I personally believe, something like a 0 when switching between DACs that cost more than $100, after equalizing for the strength of their output signal (I'm not a big believer in differences between DACs, but that didn't stop me from buying one for $1,000 that sounds just like all my other DACs...).
Best regards,
Adam
