[Skylab]

As someone who once blew up an amp, a long time ago, in a failed tube rolling experiment, I have to caution...

If you are not totally sure what you are doing, do NOT go trying whacked out tube substitutions. VERY rare is the amp where a 12SN7 can be safely subbed for a 6SN7. There are a few, but they are few and far between.

 

[jamato8]

As someone who once blew up an amp, a long time ago, in a failed tube rolling experiment, I have to caution...

If you are not totally sure what you are doing, do NOT go trying whacked out tube substitutions. VERY rare is the amp where a 12SN7 can be safely subbed for a 6SN7. There are a few, but they are few and far between.

If you can change the heater voltage there is no problem. But as you mention, there aren't many that have this ability built in.

 

[2359glenn]

As someone who once blew up an amp, a long time ago, in a failed tube rolling experiment, I have to caution...

If you are not totally sure what you are doing, do NOT go trying whacked out tube substitutions. VERY rare is the amp where a 12SN7 can be safely subbed for a 6SN7. There are a few, but they are few and far between.

gibosi's amp has a 6.3-12.6-25.2 volt switch for the SN7 socket. And if it gets left on 12.6 or 25.2 and a 6.3 volt tube
gets put in it will current limit and not burn out the tube.

 

[whirlwind]

 

As someone who once blew up an amp, a long time ago, in a failed tube rolling experiment, I have to caution...

If you are not totally sure what you are doing, do NOT go trying whacked out tube substitutions. VERY rare is the amp where a 12SN7 can be safely subbed for a 6SN7. There are a few, but they are few and far between.

gibosi's amp has a 6.3-12.6-25.2 volt switch for the SN7 socket. And if it gets left on 12.6 or 25.2 and a 6.3 volt tube
gets put in it will current limit and not burn out the tube.

Great feature, Glenn....you think of everything  

 

[zeed]

   
Notice "188-5" This is GE's EIA code. In 1945, GE purchased the Ken-Rad vacuum tube division and the factory in Owensboro, Kentucky, became GE's primary tube manufacturing facility. I would say that by the time this tube was manufactured, GE had already implemented their own designs. The rectangular mica with staggered plates, the classic Ken-Rad construction, has been replaced by the round mica and the plates have been "unstaggered", characteristic of GE designs. However, since the Ken-Rad name was recognized for quality, GE kept using it until they introduced their "5 Star" line in the mid 1950's.

 
Thank you gibosi for your detailed explanation.
 
That means this tube is quite different from the 1940's VT231 tube which however sells for a much higher price..!

 

[Demonmnky]

  Tall Raytheon 6SN7 GTB
Clarity: 6.5/10, THD: 3 (good). Bass middish w. slight sub bass roll off and noticeably low in quantity. Energy: 5.5/10. Overall 5.2/10
  (mine has a constant 'humm')

 
I have the same tube. Mine hums in my Darkvoice336i only when paired with particular power tubes. I have a short bottle one that hums with the opposite power tubes. I'm not sure if this is a documented phenomenon or just a weird coincidence. 
 
Tall bottle hums with RCA and Svetlana 6AS7Gs.
 
Short bottle hums with Mullard and GE 6080s. 

 

[DecentLevi]

You should try the Raytheon 6SN7 GT (pictured below). I had initially rated it my 3rd favorite 6SN7 tube among the 13 I tried, but I am discovering what a gem this one really is. Better clarity and bass speed / impact is really spot on, compared to my other two which I thought were my favorite that I realise to be slightly bloated bass and not quite as fast handling rhythms as this one.
 

 

[300b]

I have 118 pieces of nos tested octals...

 

[300b]

mostly 6sn7/6sl7 American early 40's...

 

[300b]

As someone who once blew up an amp, a long time ago, in a failed tube rolling experiment, I have to caution...

If you are not totally sure what you are doing, do NOT go trying whacked out tube substitutions. VERY rare is the amp where a 12SN7 can be safely subbed for a 6SN7. There are a few, but they are few and far between.

 

[300b]

currently I'm trying to build a 2 channel system around my tubes...

 

[300b]

burned up 2 pairs of NOS 2A3's by using a lower voltage variation of the same tube...

 

[300b]

I'm new to head-fi and finding difficulties posting, changing my avatar, my name ect.

 

[jamato8]

 
gibosi's amp has a 6.3-12.6-25.2 volt switch for the SN7 socket. And if it gets left on 12.6 or 25.2 and a 6.3 volt tube
gets put in it will current limit and not burn out the tube.

That is a nice feature. 

 

[Westron]

I have switched out Sylvania 12SN7 and Sophia Electric 6SN7, along with noval Mullards and found the Sophia electric to be the most pleasing. My Sophia's aren't perfectly matched, one glows a little brighter than the other but they sound pretty much exactly the same, only at very low volumes does the less bright one sound at all different.

I'm glad I had a chance to purchase the Cavalli Liquid Glass 2, it provided an awesome experience with 6.3 and 12.6 tubes, noval and octal. Sadly I have to part ways with it, if anybody is interested in a cheap package deal of the Cavalli Liquid Glass and a pair of Sophia 6SN7s let me know. I will be making a classifed ad for them soon.