Would switching amps make a big difference?

If you like the Martin-Logans with tube amplification, you might not like them with solid state.  It might be more accurate, but it will be different than what you have now.  If your room can handle them properly, get the Impression 11a loudspeakers first and then sort out the amp situation.  The ARC room correction will elevate your system performance.  That said, at the level of components you already have, $5k upgrading your source inputs coupled with acoustic room treatments is money better spent than an amp or loudspeaker switch.

Any thoughts on which tube amps work best with Martin Logan speakers?

Any thoughts on which tube amps work best with Martin Logan speakers?

The problem you are up against is that Martin Logan is trying to make an ESL (which is normally a pretty good combination with tubes) to work with solid state amps. The issue is that ESLs have an impedance curve that typically varies by about 9 or 10:1. Whatever impedance it has in the bass, it will be about 1/9th or 1/10th of that at 20KHz.


Since solid state amps tend to double power as impedance is halved, right away you can see that the MLs will be a bit bright if the amp actually got away with that. So they make the speaker really low impedance and that prevents the amp from being as bright because even solid state amps have troubles driving 0.5 ohms. But fortunately there isn’t a lot of energy up there so the amp isn't required to make a whole lot of power at that frequency. But the flip side is no tube amp can drive such a low impedance and so makes no power at all.


If you find out that you prefer tubes over solid state (maybe because its not as bright) you have a problem- how to drive such a low impedance? That is what the ZEROs are for. IMO/IME you are better off putting out the match rather than putting out the fire- get a set of ZEROs and then your amp will drive the MLs pretty well. I know it works- we’ve had customers with MLs for nearly 30 years. You’ll get your highs back (and likely the amp will sound better overall) without it being bright.

I had ML speakers and a McIntosh tube preamp with a pair of McIntosh m275 bridge to mono. I was happier with the tube preamp and a set of 501s. I have always liked a tube preamp with a solid state amp.

I currently have ML ESL 9s and  a Parasound A21+ amp.  I don't know the output impedance of the amp, but it seems to match well with the ML speakers.  Maybe someone else can confirm whether it's a good match by the numbers.