What's the best 6NS7 tube you have tried in your Atma-Sphere MP-3 preamp?

For some reason the moderators took down my previous post so I’ll try this again.

I tried 4 different pairs of different makes and brands of 6SN7 tubes and the synergy with my MICROZOTL MZ3 Headphone Amp / Preamp / Integrated Amp with the Sylvania 6SN7GT Bad Boys and/or Sylvania JAN-CHS-6SN7GT Bad Boys are some of the best sounding tubes I’ve ever heard. So I finally settled on the Bad Boys. These are the key distinguishing features to recognize a Bad Boy tube.

1) 3 hole black T plates

2) Bottom getter flashing 1/3 way up the tube

3) Shiny silver top and bottom rectangular mica. The top mica has three small triangular edges bent down on each side.

4) Copper grid posts

5) Date code of 2xx(or possibly 1xx or 3xx) were 1, 2 or 3 represent 1951, 1952 or 1953 and xx represents the week.

6) Full black bottom base with Sylvania 6SN7GT and/or Sylvania JAN-CHS-6SN7GT in green letters. And yes the Sylvania JAN-CHS-6SN7GT with full black bottom base with green lettering are also Bad Boys. So you’ve actually have two options here.

7) Look for the tall bottle versions only.

‘JAN’ stands for ‘Joint Army-Navy’, and was meant to indicate that the tubes labeled as such were ‘passed’ for military use. However, no additional criteria that were not already fulfilled by the 6SN7GT specification were known to have been imposed. ‘JAN’ labeled tubes are identical to non-JAN tubes of the same vintage and construction.

Sylvania 6SN7GT and the Sylvania JAN-CHS-6SN7GT Bad Boys [3 holes in each plate, copper grid posts, bottom getter, green labels, black base and plates, vertical date code (read from top-down) ‘2xx’ with ‘xx’ representing week #, ’polished’ silvery rectangular mica]

The Sylvania 6SN7-GT and the Sylvania JAN-CHS-6SN7GT Bad Boys was made from late 1951, week 39 ("1/39") to early 1953, week 13 ("3/13"). They have black T-plates -3 holes, Copper grids, Bottom getter, "polished" rectangular mica, green labels on black base.

I haven’t heard any of the Chinese tubes recommended by Don Sachs, though I’m tempted now. ;-) My go-to 6SN7’s for both my Williamson amps and my Aikido preamp, are:

1) GE 6SN7GTA or B. Well-made, non-microphonic, consistent. Open, textured sound. Can be had new or test-like-new for around $50.

2) Sylvania 6SN7WGT, with parallel (not angled) plates. Beautiful midrange. Around $75-100 each now, but people pay a lot more than that for new boutique varieties.

I currently use the GE’s in the amps, as they are a bit more neutral, and the Sylvanias in the preamp. It’s a nice combination.

@tyray , my bad--I referred to those Sylvanias as '55 Bad Boys. I just found the email regarding that batch of 6SN7s that the previous owner sent me, and they are ’52 Bad Boys.

@immatthewj,

Matt no worries, I’m just glad the moderator’s had to good sense to leave my post alone this time. It’s very easy to get a tube you thought is a Bad Boy and it is not, and it’s just as easy to miss out on a Bad Boy because you’re under the impression that only the '52’s are Bad Boys.

The best 6SN7 we've heard so far is the Linlai. There is a globe variant that I don't think will work as well- the globe resonates easily!

Of the NOS tubes the KenRad gets the highest marks.

The 12AU7 should not be ignored- it has the bigger effect in the line stage of the MP-3. The best of the NOS tubes has been the Amperex Bugle Boy 7316. The Amperex Bugle Boy 12AU7 is not slouch either. We have some good comments from customers about the Gold Lion reissue 12AU7 and also the Northern Sound 12AU7.

We have extended the range of the servo circuit in the MP-3, allowing it to work with a wider range of mismatch in the 6SN7 internal sections. It also reduces the DC Offset at the output by a factor of 10 or more, down to a few fractions of a milliVolt.