2. amps-preamps
  3. 1392024857

Power tubes as drivers -- Line Magnetic

I just purchased a LM 518 IA, which is a 22 watt SET integrated using 845 tubes. The amp uses 2 6L6 as drivers and 12ax7 for input.

I'm picking up the amp this week, and although I haven't seen the user manual yet, From what I can gather, virtually any power tetrode or pentode, including EL-34, KT-88, 6L6 and 6V6 can be used as a driver in this amp. Of course that means I'm getting ready to try a buncha tubes.

My current thought is to pick up decent, but not expensive, current production samples of the various tubes (probably all made by the same manufacturer to maintain some control) so I can get a handle on which sound I prefer most, then move on to more expensive and probably NOS versions of those tubes I like best. Just checking in with the community for reality check on if this makes sense to anyone else.

Also, I've seen on various tube sellers sites reference to "this (noisy/micro phonic) tube is only suitable for use in a driver stage . . . ." Can I infer from this that I can get away with slightly dodgy driver tubes and thus buy really fancy schmancy tubes in low grade and still achieve good results?

Will appreciate your thoughts.

D
dkidknow
dkidknow OP
59 posts
 
Thanks Jrinker. I'll give Matthew a call.

I love my dealer (In Living Stereo), and they thought my strategy outlined above would be a useful approach, but then I called a very reputable tube guy who thought it would be a complete waste of time. So far, it's been a perfect microcosm of our hobby, with two experts completely at odds with one another! At least it's really fun figuring it all out.

D
chayro
2,983 posts
 
Didn't pick up the amp and already replacing the tubes. You are a true audiophile. Enjoy your new amp.
tboooe's avatar
tboooe
1,009 posts
 
Dkidknow, what speakers are you driving with the 518?
atmasphere's avatar
atmasphere
11,778 posts
 
Sounds like the amplifier operates class A2. Otherwise one would not need such a hefty driver tube.
dkidknow OP
59 posts
 
Chayro: Apparently, I absolutely am that guy! I've been enjoying the amp for a couple days now.

Tb: I'm driving Merlin TSM-MME. I also tried the 15W leben integrated, but it really didn't have the grunt to drive the Merlins. I'm not sure if it's the extra wattage or the current capability of the 845s, but the LM was a much better match for my speakers.

Ralph: I had never heard of class A2 until now. I just did a little reading-- very interesting. Until then, I would have had to use my best Nigel Tufnel accent to say class A2 is "one louder" than typical class A! Thanks for the info.
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