Not to say that you MUST find depth in your K/Q701s don't get me wrong. It can be that the headphone doesn't fit you well physically, or sonically. As I've said before, the perception of soundstage is a really complex and subjective topic.
Just give them the benefit of doubt if you haven't tried them on a more refined setup yet. I might surprise you!
PS. Yeah, I've been quite skeptical about differences between different quality SS amps, don't blame you if you're still like I was before having quite a few amplifiers to compare. Differences are there, not huge for sure, but sometimes a little difference can make a big impact on how we perceive fine details in the deep of our recordings.
I knew the 701 was falling out of my favor when I started noticing how annoying the headband bumps are. "Hmm, how come those didn't annoy me before?" lol.
A better sound card soon is a possibility, just out of curiosity and to have a stronger amp available if nothing else, but an external amp better than an E09k or similar would require more reading and convincing at this time.
I'd love to get more depth out of the 701 since the rest of it sounds so interesting and different. It's getting harder to enjoy them musically, but I guess I enjoy them more on an analytical level anyway. The Q701 is like a fast car you only use at the track. It's not well-mannered enough to drive every day, but you keep it around just so once in a while you can use it and say, "Wow, that's crazy."
Obviously some people love using them all the time. Maybe doing the full bass mod again will make them more interesting. It's funny listening to a 701 and turning the bass down.
And then there's that. There's a review around here or somewhere though that says the K7XX is smaller soundstage and like an AKG HD600/HD650, and that it no longer has what makes the K and Q special in the first place. Guess more reading is in order.