I'd also suggest trying both headphones on different systems if possible since both react to different amp designs (OTL, SET, etc) differently. For me the HD650/6XX sounds best on a OTL amp while the HD58X sounds best on a hybrid or neutral/bright SS.
The only headphone amps I own are the Magni 3 I bought a few weeks ago while waiting on my 58X's to arrive, and a Fiio E17. Really happy with the Magni so far, as not only does it go with my new headphones quite well, but it has brought new life to my old pair of DT 990 Pro's, which I've always felt needed a little more power than the E17 could give.
I do plan on getting a tube amp at some point, so maybe I'll keep hold of the 6XX's at least until then.
Any suggestions for a decent tube amp that wouldn't hurt my pocket too much? Maybe around £100-£150 or cheaper?
Perhaps I should go for a Vali 2 to stack with my Magni?
Burn-in is real and you can measure it, now will the differences be enough to notice in every headphone? No... but there is another part of burn-in, the psychological, takes time for you to get used to the headphone, to understand all it's details and how capable it is I think this is even more present for the HD650. Spend a good time with it and when not using let it play some stuff.
Took me little more than 2 weeks to really notice the areas where the HD58X was superior to the SHP9500
This video shows how much can it change with burn in, but this headphone is known to change, so it won't be so crazy for a Sennheiser I think
Thanks for the advice and video explanation.
I certainly am going to give it every chance to see what differences I can hear before deciding whether to part with one of them.
Although I said I didn't hear much of a difference, that's not to say I didn't hear any at all, I did. There were some I noticed quite quickly, such as the bass not being quite as punchy as the 58X's (yet still more present than I expected, which I was pleased about), and also, to me at least, the soundstage sounded narrower.
However, one of the selling points to me for buying this headphone was reading about the 'magical mids', and I found it difficult to separate both headphones in this area in the brief time I've spent with them.
As much as I'm going to give these headphones time, I also don't want to fall into the trap that
@Jaywalk3r mentioned previously, where I convince myself I hear more of a difference than I really do..
For normal usage I think it’d be hard to notice the change because if you listen for 2 hours a day, 200 hours would be 100 days = more than 3 months. If anything it would be similar to watching a puppy grow up. It won’t be a daily noticeable change, instead more like “but 3 months ago...”
IME Grados are consistently subject to burn-in - I have never met a pair that didn’t. My HD6XX maybe went through some burn in, as for the HD58X I’m not sure
I had the exact same thought on this earlier.
For example, I've had my DT 990's for over 2 years, but I've never really noticed any difference with them in that time, but if the change is very gradual, then I'm not going to notice it anyway...