2. amps-preamps
  3. 123463-1475

6sn7 or 6sl7

I have an Almarro A318-B and would like to swap out one of the preamp tubes, but I cannot decide which one would have the greatest affect on the sound. The Almarro uses a 6sl7 as the input tube and the 6sn7 as an "anode follower" (I'm not sure what that is?). I can only afford to do one now, so hence my dilemma. I have three different 6sn7's at the moment with the following characteristics: RCA 6SN7-GTB that has a detailed but lush presentation; Electro-Harmonix that has a very detailed and airy sound, but is a little flat and edgy, and last is the stock Russian 6H8C that images very well but has limited frequency extension. I have only used the stock Russian 6sl7 (6H9C) with all of these because that is the only one I have. 

Any insight would be much appreciated. 

Thanks!! 
enobenetto
atmasphere's avatar
atmasphere
7,068 posts
 
The two are not really all that interchangeable due to different characteristics. You can place a 6SN7 in a 6SL7 socket without damage, but it won't sound right because the bias points for a 6SL7 are so different.
maxmad
182 posts
 

If you can affort and find, try NOS Tung Sol 6SU7, which is 100% replacement of 6SL7. This tube sounds fantastic.

For 6SN7 I highly recommend NOS Mullard ECC33, brown base, short bottle, but thats only if your amp can take that tube, ask Almarro guys directly. Other than that, try Italian made NOS Fivre 6SN7, brown base, they will match Tung Sol perfectly.

enobenetto OP
52 posts
 
Thanks both of you for the responses. I will look into the Tung-Sols. The Mullard seems to be harder to come by unless I buy a new reissue but those have mixed reviews. I think this will be an interesting tube match. I might even get two different 6sl7 to mix and match with the other 6sn7. This is fairly new to me, but it is interesting. I guess it is not too cost prohibitive because you only get one choice of power tubes with the Almarro and they are cheap.
salectric
683 posts
 
There are so many varieties of 6SL7 and 6SN7 tubes available that it is hard to generalize.  But one thing I would say is certain: for a hobbyist, as opposed to a manufacturer, use only vintage Old Stock.  Why bother with modern reissues when superior sounding vintage tubes are available at such reasonable prices?  A mfr needs a large supply of identical tubes.  A hobbyist doesn't need hundreds of the same tube; he just needs a couple of whatever tube sounds best.

For the 6SL7 slot my very favorite is a Sylvania VT-229 (military designation for a 6SL7) black plate from the 1950s or 1960s.  I have several purchased on EBay which sound superb.  My suggestion is to try several varieties of vintage tubes by buying inexpensive "used but still test good" on EBay.  You will quickly form your own opinions about what you like and what you don't.

salectric
683 posts
 
And I should also mention another favorite 6SL7 variant---Brimsr CV1985.  In the right application it too is superb: fast, airy and detailed and very deep tight bass.  A little hard to find but worth grabbing when you see one.  A real workhorse too.
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