In regards to the LS-25 and VT-100 debate, I agree with Gmorris about the 6H23 tubes from Kevin Deal @ Upscale Audio. For the money, this is by far the best upgrade to the LS-25 (original version). In fact, I was all ready to send my LS-25 in for the MKII upgrade until I put the 6H23 tubes in. The other thing that should be known is the fact that my LS-25 is modified with signature infinicaps (hot rods). I did a side by side comparison with my pre-amp both at the dealer and at home, and 4 audiophile friends preferred my LS-25 (with the mods and 6h23 tubes) to the MKII. The dealer admitted that they were suprised at this comparison results, but agreed when they heard the comparison. I also agree that the VT100MK2 and original version both sound better with the 6H23 tubes than the VT100MKIII. Again the comparison was with my VT100 original version, modified with the signature infinicaps, several resistor changes, and misc. mods here and there.
In summary, If you are not a tweeker, then the LS-25MKII and the VT100MKIII are probably the best sounding out of the LS-25/VT-100 combo. If you have Electronics Engineering Technician abilities, a good soldering iron, NOS Tubes, then I will confidently say all bets are off that the latest revisions sound best. Keep in mind, there are not NOS equivalents for 6H30... What you buy is the best it will ever sound. If you are talking about ARC REF components -- that is a whole different ball game... for the better. The REF2MKII is a lovely pre-amp, and is awesome mated with the Ref 300 amps. ARC made the revision to the new circuit topology purely for Manufacturability, borrowing from the REF technology to make the sound better to justify cost increases... Just a rumor I have heard from more than one source...
In summary, If you are not a tweeker, then the LS-25MKII and the VT100MKIII are probably the best sounding out of the LS-25/VT-100 combo. If you have Electronics Engineering Technician abilities, a good soldering iron, NOS Tubes, then I will confidently say all bets are off that the latest revisions sound best. Keep in mind, there are not NOS equivalents for 6H30... What you buy is the best it will ever sound. If you are talking about ARC REF components -- that is a whole different ball game... for the better. The REF2MKII is a lovely pre-amp, and is awesome mated with the Ref 300 amps. ARC made the revision to the new circuit topology purely for Manufacturability, borrowing from the REF technology to make the sound better to justify cost increases... Just a rumor I have heard from more than one source...