Supratek Tubes and Tube Swappin' for Everybody

Bwhite,

You bring up a good point that new Supratek owners should take notice of. The Suprateks are ridiculously sensitive to microphony (not a good thing). I really don't know a linestage preamp that is more sensitive. You essentially need phono-grade quality tubes for line-grade application. If I had a gripe about the Supratek design, this would be it. And for this reason I hate selling 6SN7 to Supratek owners.

I agree the CV181 does not work in my preamp. I think you may have misread what I posted. It's a tube that I do not recommend (for the Supratek or for nearly all other 6SN7 applications).

I have Ken Rads with identical base prints - down to the alphanumeric date codes - but clearly different builds (tin versus copper grid posts, different mica varients, etc.). There might be audible differences as you say (I still can't hear marginal differences myself, much less "dramatic" ones). Whether you or I believe there are sonic differences or not, base print is a virtually useless criteria.

I also find the 350B midrange very neutral, which is what I love about this tube. In comparision, the EL34 and EL37 midrange is a touch bloomy and warm. The 350B sounds fast and accurate. It does not, however, sound powerful IME. There is a leaness to the presentation that (reminds me of KT66 tubes) compared to EL37 and 6L6 tubes. The 6F6 also has possesses this leaness, and it too is very fast (faster even) and "accurate" like the 350B.

Fiddler,

IME, the Sylvania Bad Boys is comparitively "dry" sounding versus the Tung Sol's more liquid, "wet" sound. For clarification's sake, I am not using the adjective "dry" with any negative connotation. It's a matter of perference. I like the Bad Boys; they've got better control of attack and decay then the Tung Sols, and the Sylvania 6SN7GT '52 have more spatial seperate and thus sound slightly more resolved. The high frequencies have an uncanny air to them. However, the Tung Sols simply reproduces harmonics that is extremely beautiful to my ears .... a bit more full and palpable. And they sound more balanced from top to bottom.

I confirm the problem with the 6106 regulator when use for the Chenin. There is no problem on CD source. In fact you can crank up the volume to the max (no music playing) and you will not hear any hum at all or tube rush sound. Not for the phono section though! With the 6106 as a rectifier, using the same test method, there is a loud "chugging" sound when the volume pot reached about two O'clock.

So for the Chardonnay, the 6106 will work without problem since the one that is affected is the phono section.

I was using 6F6G on my Chenin. But I am now enjoying a GE 7518 as regulators. It adds a little "muscle" to the already superb phono section (not that I am complaining!). I like the RCA 6L6GC'a also.

It seems to me, after reading a lot of comments and experiences about regulators and rectifiers, that the Syrah, Chenin, Chardonnay and the other preamps have a different voltage requirements. I think as far as the tube rolling issue is concern, the only tube that is "universally acceptable" based on others experienced to everybody is the 6SN7's for the Suprateks. The others vary and should be specific to each model only.

I think....

Amandarae - Are you sure that you are using the 7518 or is it the 7581? The 7518 only has a 2.5v heater and if that is what you are using you might want to get the fire extinguisher handy. You are right about different voltage requirements but the difference is mainly between the linestage only versions and the full-blown preamp with phonostage. SupraTek owners with the phonostages will have higher current requirements that will restrict the use of some of the lesser rectifiers and pentodes.

Anyone who has a phonestage in their SupraTek preamp might want to check with Mick before rolling power-suppply tubes.

Jazzdude,

My mistake! It is a 7581 (GE with pink base). I made a typo on my post.

".... linestage only versions and the full-blown preamp with phonostage. SupraTek owners with the phonostages will have higher current requirements that will restrict the use of some of the lesser rectifiers and pentodes...."

Exactly! This is the main reason why in the phono stage, the "chugging" sound was produced since the 6106 is basically a 5Y3GT isn't it?

regards