Preamp Deal of the Century

Jewel I tend to agree that there is less difference between the 6SN7's and 5881 tubes. I've tried 5 different types of these tubes including National Union, Ken Rad, Sylvania, RCA and the stock tubes. There are differences but they tend to be rather subtle. I find the rectifier the same having tried several of the recommended ones. I am currently using a BEL which is a manufactured in India and was a supplier to among others Mullard.

I agree with Fiddler. Where I have noted the most significant changes and improvements in the Syrah's performance is in the regulator position. The 6L6 type seems to open up the dynamics on the pre to a greater degree than the 5881's, greater plate voltage maybe? And for the most significant improvement to date per Ecclectique (thank you David for this great recommendation) you must try the 6F6g. Relatively cheap NOS, less than 50.00 bought me a pair of Brimars and I was stunned at the enhanced dynamics and the bass, oh the bass. Everyone must try this tube. They are readily available and can be purchased used at considerably less than 50.00 for the pair.

Hi Tubegroover: You know what, initially I too was looking for some NOS 6F6g based on Ecclectique's recommendation but the fella (Mike) at www.vacuumtubes.com was telling me that he didn't think 6F6g's could be direct replacements for 6L6 application. I decided not to take the chance - oh well! In fact at the vacuumtubes.com's website they list 6F6gs at $20 new and $10 used without mentioning any brand names etc. But it's cool, I really didn't mind the process as I've been wanting to try this for a while. And really, it's all been quite fun so far. Just the process of tube hunting and then waiting in anticipation was fun & and educational in itself. Now I'm going to set my focus on getting damping material and possibly some DH cones; oh yes and some 6F6g tubes.

Jewel, Glad you're having fun! Finding good 6SN7's is actually quite difficult because most are microphonic in the Syrah. I estimate that 1 out of 10 6SN7's you'll find will be troublesome.

Bwhite: I know you mentioned in one of your earlier posts that the Kenrad Blk-Glass(6sn7) worked best for you but have you tried the TungSol (6sn7) black-glass in your setup? I wonder how they perform (sound & microphonics) against the kenrads. I called my tube vendor yesterday and asked about the microphonics and whether it was worth sending these back to try a different pair. He told me, most if not all old 6sn7 tubes would have microphonics, that's a given. However, I'm thinking of calling him back today to see what it would cost to replace the kenrads with a pair of TungSol blk-glass since I'm still within my 10-day return/exchange period. And perhaps pick up a pair of 6F6g in the process.

Jewel - *I* liked the KenRad Black Glass tubes and I like the Tung-Sol Round Plates. They are both very good choices. Honestly, the stock 6Sn7's sound a bit like a cross between both tubes - somewhat closer to the Tung-Sol but less harmonically complex.

The Tung-Sol Round Plates are sweeter, more open, and have less midrange bloom than the Ken Rads.

Ultimately, the tubes you choose as "best" will depend 100% on your listening preference and the rest of your system. No-one can tell you what is best for YOU.

It is good to attempt to determine what character your system needs before seeking out tubes. I don't know what the rest of your system is so its difficult for me to determine (guess) its sonic signature. Even if I did know what your system consisted of, odds are your listening preference is different than mine to some respects and my choice in tubes would not be correct for you.

So.. that said, with the stock tubes in your Supratek, what elements do you think would be beneficial to your system?

Be cautious when buying "names/model numbers" of tubes vs. construction of tubes. Often times a tube will carry a specific number yet the internal construction may be different. The Tung-Sol Round Plate referrs to a specific construction or type of Tung-Sol 6SN7GT which is to my knowledge MUCH different sounding than the more common "black glass" Tung-Sol 6SN7GT.

Vingage is also important. Tubes can sound different from one another, even on a month-to-month basis in some cases - ie; January manufacture sounds different than February. To me, a matched manufacture date is VERY important otherwise the tubes, however identical in appearance, can sound somewhat different. Also... matching the electrical ouput is important because the L/R channels on the Supratek cannot be biased. A severely mis-matched pair of tubes could result in a soundstage that leans to one side or the other because the gain on one channel is greater than the other.

Likewise - just because a tube is a "6F6G" doesn't mean its THE 6F6G that everyone is talking about. THE 6F6G you want, I believe is the Sylvania 6F6G - clear glass - green print or the somewhat different - National Union black glass 6F6G. Ebay is a GREAT place to research tubes and to get more familiar with the internal construction. For an example, go do a search on Ebay for "6F6G" and see how many different versions there are.