The GS1000 is extremely fuzzy with amp's and need a loooong burn-in..
With the right amp and 500- op more burn in, you can listen loud (I seldom do this myself) without the down and upper distorsion..
They do excel in low volume though
What is the average burn-in time of a tube amp though?
Beware of generalizations regarding these cans. Despite certain "tribal truths" that many accept around here, low-impedance cans often work very well with OTL tube amps, for instance. Lately, I've been enjoying my GS1K immensely with the Proceed PCD3, my Woo 3 and fifties/sixties classic Blue Note jazz on CD. Some "experts" (they know who they are and you probably do, too) around here will insist this can't be true because you MUST have a transformer coupled tube or solid state amp to properly power low-impedance phones. And as is sometimes the case, these "experts" are wrong. Dead wrong.
I want the Woo 3+, seeing as you have the older model how well do you like it?