Mr Chance,
You're very welcome, and I hope the following helps.
I haven't been fortunate enough to hear the Audio-Technica W5000s, so I can't really comment on them so much as the HD600s, which I had for a brief period years ago and are also very close to the HD650s. For Jazz and classical, especially with female vocals, you probably want a smooth and high resolution mid-range, with a little sparkle up top. I agree, I also tend to really like great air or space in the sound, making live recordings "feel" live, so soundstage would also be important as well.
It is hard for me to say what new production tubes would benefit you the most, as I haven't tried too many, but I have had good luck with the Macintosh KT-88s, which are my daily multi-use pair. However, you may find that you really like the EL34s in general, which I've found to add a great amount of air with the addition of a little extra mid-range magic, especially in the upper mid-range. You could try the new production Mullards by New Sensor Corporation, or the SED Winged "C", both Russian companies, if just to see if they are your flavor, but ultimately either the Telefunken, which have really great upper mid-range and highs, or the NOS Mullards from the Blackburn factory, which give some of the best mid-range and sound a bit more full than the Telefunkens, will probably give you the best in overall sound quality for this type.
The same really goes for the 12au7s, I've only tried the Telefunken smooth plate, but it was very nice in upper frequencies, while the Mullards are generally mid-range beasts, with the Brimars being similar, but giving just a bit more resolution; the Mullards may be a little too laid-back with your HD600s/cable, which might over-emphasis the Senn "veil". Also, many have had good luck with the Amperex, either orange globe or bugle boys. As far as new production, many have found the Psvane 12au7, mark II I believe, to be very nice, and may work well for you; Victor is a good source of information on these I believe. However, it may be best to try a different power tube first and then see where you end up. A pretty good, not the best though, NOS 12au7 are the RCA clear tops, which should sound much better than the Made in China stamped stock tubes.
I hope this helps, but let us know. Also, fellow headfier mhamel has quite a few new production variants and was planning on letting us know how each ultimately turned out, so stay tuned!
JK-47,
It was probably the best idea to just return them, even if the price was really good, as the vast variation may indicate that there is an issue with one of the tubes. Do you happen to have a Tube Manual, that is one that lists the readings for each tube at nominal value? G.E.'s manual is considered the best and most comprehensive, but some may also include these voltages, along with the GM. Anyway, I'm sure another good deal will pop up at some point, patience is everything, and so is getting what you expect, which in this case was a matched pair.
I like the system, thanks for sharing! Many of us here can attest that this audio stuff is really a journey, not just a destination, and most of us started out with pretty basic systems that we have added to or tweaked over the years. No need to rush in and spend thousands upon thousands, unless you are confident in what you ultimately want and have had exposure to everything you end up buying (in a perfect world, right!). It is also always hard to gauge someones ears and preferences, but even a great set of ears can usually be able to discern differences in a lower resolution system, at least in general. The source and the end, in my opinion, are the most important, so starting with a high quality format, fed to a quality DAC, and ultimately to a nice pair of speakers/cans is very important. Not that amplifiers are not important, as we have all experienced with the Elekit, but they really build upon the source and then affect everything they feed; the old saying probably reigns true here though, garbage in, garbage out, no matter how good the amplifier. Anyway, you have a fine system that should be giving you some really great sound!
john57,
The EL34's are a very nice sounding tube, however I would be reluctant to call them the most transparent. All tubes add distortion in the 3rd and 4th harmonics, as they are often referred to as distortion tubes. However, distortion in these harmonics is different than the 1st and/or 2nd, that we generally associated to distortion in sound, and to many make the music actually sound more organic and natural... similar to how a live album sounds compared to a tightly controlled studio album. With that said, the EL34's do change the sound and add their own flavor. I've found that while some of the EL34s have great resolution, generally the KT-66 and KT-88 varieties have been more pronounced, with more weight/body, and better low-end resolution. So, it is really hard to say which of the tubes that the Elekit can use, and that I've tried, are the most transparent, as they all add a little bit of their own flavor, while taking away other qualities as well. I know that's probably not really the answer you were looking for, but honestly the best way to find out is to use your own system/ears, experiment with different types, and see where the chips fall.
