This is the first time I've ever posted on a hi-fi site but could really use some expert advice.
I just recently purchased a slightly-used Luxman SQ-38u froma Luxman dealer. He promised me that the amp is essentially like-new and even offered the full 2-year warranty through his shop. Given that it doesn't need break-in time (since it's not new), I was surprised by the sound. The mid-range itself sounds really great. The low-bass is also pretty good for a tube amp. But there seems to be basically no low-mids whatsoever. So, for example, with low notes on a cello, or bass guitar, you can hear the boomy low bass but not any defintion. It's just a big hole in the spectrum.
Might this be a problem with the amp? If it had a bad tube, would it cause frequency dropout like this or more obvious artefacts?
If I can somehow find some reassurance that the amp is performing like-new, then I would conclude that it's just a weird mismatch with my speakers (PMC PMC DB1i's). But I don't want to go in circles demoing or replacing my speakers if the Luxman itself is not performing as it should.
Any thoughts would be much appreciated! Thanks!