Never finished my sentence, though buy a decent value amp and be "satisfied for a while" does imply the second part, that you can buy something more sophisticated later on. It still is a semi dubious expenditure of capital in the beginning as pride of ownership and craftsmanship does not necessarily lead to a substantial increase of sound quality, though they often do whether it is actual improvement or perceived improvement is irrelevant, as long as the enjoyment is real. I would still argue that subtle changes are the more realistic expectation going forward when it comes to upgrading amps, and that if you do notice a large sweeping change, than it usually means something was not working correctly before, or more than likely some expectation bias is involved. That is not a fault though, many a life has been dedicated to the pursuit of the subtle changes from one object to another, just look at vino's or cigar aficionados for an example. I think sometimes we confuse new people in the hobby by making the changes seem more grand than they actually are, it not be our intention, as to us those changes are very real and provide additional nuance. But subjectively, they are still small changes that rarely match the dollar amount involved. (As a side note, I would rather put my money towards a nicer high quality amp than a rare and expensive cigar, the amp will last a lot longer and ultimately provide more enjoyment in the long run, unless you are an aficionado that just enjoys the smell and not the smoke).
I did avoid the cheap word, although decent value and cheap often go hand in hand. I hesitate to recommend an actual product as im not advocating a change in amps to the op at this time, after all, he just purchased this one and he should have a chance to enjoy it first. I will avoid defending the, unmentioned by myself, thx amp series, as it is non applicable to the original post. I have never heard the jds labs element 2, but I did hear the original element and it a pretty decent value dac/amp, and would certainly hold its own against most amps, and for a wide variety of headphones as well.
And back to tubes, I am one of those that does hear changes from one tube to the next, at least most of the time as some do sound very close indeed, but i have yet to find a tube that did not sound good to me, at least in some way. I could be flawed i admit, but I do find the differences as more subtle than sweeping. Your mileage may vary, but i still advise that a 400 dollar set of tubes is unlikely to unlock a 350 dollar increase of sound quality, and besides the point to boot, the question was never sound quality in the first place, but rather a question of noticing the differences in two very different amps with completely different architecture. I would focus on enjoying what you have, let your brain burn in a bit before spending more money on tubes that will only have subtle changes. Like I stated earlier, the human brain is very good at filtering out distortion, particularly of the tube variety kind (if it didn't than we would notice a difference much more immediately and not in a good way). Got to give your brain time to adjust and let the small nuances of the sound grow on you. It certainly can sound very pleasant, but as it is subtle and linked strongly to our perception, can take time to appreciate, and indeed may not end up being your cup of tea. Only time will tell.
