Jbhorn, Kara at deHavilland will tell you that experimenting with 6sn7 tubes with her preamp is akin to trying different wines. Of all the tweaks I have made to my system, the ones that were immediately the most audible were from trying the many differing vintage 6sn7 tubes. By the way, the vintage tubes are, without question, much better than any of the new 6sn7 tubes...at least for this preamp! For example, the Raytheon wgt's have a punchier bass but a slightly softer top end...the tung sol round plates lack a bit of bass punch but are the most true across the whole spectrum...IMHO. So, in answer to your question...yes, tube rolling with the deHavilland Ultraverve can make huge sonic changes in your system's overall sound signiture. Please email me for more info on 6sn7 tubes and any other questions you might have concerning this preamp, etc. I have had mine for about three years. I can't comment on you particular speakers though (I have B&W 802d's).