[drhoon]

Any expert 6SN7 help me identify what this is?
The seller seemed reliable and told me they were Sylvania but there were no labels. I couldn't find any information on unbranded Sylvania and just wanted to see if I can narrow down more specifically.
 
http://imgur.com/a/KdtuG

[luckyguy]

Not an expert but have a pre amp and two Heath monoblocs using the 6SN7.  These look like 2 hole Sylvanias currently misnamed Bad Boys probably pre 1951.  I replaced these 2 holers with true Bad Boys having 3 rivet holes in each post for a bit more punch in the upper and lower registers, though the 2 holers are no slouch.  Sound is smooth and mellow and on par with any Raytheon/RCA produced in that period.  Good tube, make sure 2 sides match up.  I have some NOS testing tubes as pictured if you need more. 

[drhoon]

Cool appreciate it

[DaveC113]

Not an expert but have a pre amp and two Heath monoblocs using the 6SN7.  These look like 2 hole Sylvanias currently misnamed Bad Boys probably pre 1951.  I replaced these 2 holers with true Bad Boys having 3 rivet holes in each post for a bit more punch in the upper and lower registers, though the 2 holers are no slouch.  Sound is smooth and mellow and on par with any Raytheon/RCA produced in that period.  Good tube, make sure 2 sides match up.  I have some NOS testing tubes as pictured if you need more.

Yup, decent tubes and often sold for far too much $ as "bad boys", but they aren't the 3-hole version which are the true "bad boys".

I've got a TON of NOS 6SN7 and truth is there are no bad ones at all. Many are cheaper than new production tubes and will be more reliable. My favorites are the 5692 for their low noise and the Russian metal-base black-plate tubes, 6N8S I think... the hole-plate 1578 (or whatever) versions are lots of cash but probably not worth it. I don't go for the super high $ tubes though, it's often hype and lots more $ for a subtle variation.

[dolsey01]

 

[drhoon]

 

[luckyguy]

Yup, decent tubes and often sold for far too much $ as "bad boys", but they aren't the 3-hole version which are the true "bad boys".

I've got a TON of NOS 6SN7 and truth is there are no bad ones at all. Many are cheaper than new production tubes and will be more reliable. My favorites are the 5692 for their low noise and the Russian metal-base black-plate tubes, 6N8S I think... the hole-plate 1578 (or whatever) versions are lots of cash but probably not worth it. I don't go for the super high $ tubes though, it's often hype and lots more $ for a subtle variation.

Oops!  Forgot about that wonderful Mil. spec. 5692 RCA which I agree is a very quiet, smooth tube.  Forgot I switched to these in my pre amp and have been very happy since.  These are getting pricey though.  Thanks for the reminder, Dave.