Is my ARC LS25 MkI holding back the sound?

[birdland]

I've read many posts in here recently about how ARC's REF pre-amps are so much better than the LS line. I really want to get an opinion of what is going on.

For a very long time, I had two VT100 Mk IIs bi-amping my Martin Logan SL3s (NOTE no external cross-over). The pre-amp is an ARC LS25 Mk I (4 - 6922 tubes).

I wanted to simplify my setup and upgrade. I read very positive reviews of the REF150 amp. So I recently purchased a used REF150 and I am still using my LS25 Mk I pre-amp. The sound improved a bit but not to the extent I was expecting.

So the question I have, is my LS25 Mk I pre-amp holding back what the REF150 can provide? If so, what would be the minimum ARC pre-amp I could use to make an significant difference in the sound?

I really like my LS25 because I can tweak the sound by changing the 6922 tubes but if it is limiting my musical experience, I probably should change it out.

Thanks,
Walter