Big differences, even between similar types (i.e. SS vs SS, or tube vs. tube) are to be expected. This is normal.
Ignorance, that is, lack of experience in comparing, can cause a person to be content, but it also is the enemy of progress and better sound. When you do comparisons you find out there IS far better sound to be had. So, be prepared to open your wallet to get it. If you don't want to spend money, stop comparing. Simple. But, I suspect you had some reservations, problems with your amp's sound, or else you may not have been comparing.
So, you're working the permutations, good! So, there's no problem here, just different outcomes based on what each amp does. No big deal. If you are not perfectly content with either one, now that you have heard the variance, keep looking. You'll find your "perfect" if you keep at it.
My goal in system building has been to accept no significant shortcomings and to be eminently content with the sound of all media/music played back. That is far harder to do than it might seem. Even systems at $40-50K can have troubles in certain aspects of performance. So, don't be upset if an affordable system has some shortcomings.